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Prof. Andy Tanenbaum Retires From Vrije University

When Linus Torvalds first announced his new operating system project ("just a hobby, won't be big and professional like gnu"), he aimed the announcement at users of Minix for a good reason: Minix (you can download the latest from the Minix home page) was the kind of OS that tinkerers could afford to look at, and it was intended as an educational tool. Minix's creator, Professor Andrew Stuart "Andy" Tanenbaum, described his academic-oriented microkernel OS as a hobby, too, in the now-famous online discussion with Linus and others. New submitter Thijssss (655388) writes with word that Tanenbaum, whose educational endeavors led indirectly to the birth of Linux, is finally retiring. "He has been at the Vrije Universiteit for 43 years, but everything must eventually end."

45 of 136 comments (clear)

  1. His epitaph in future years: by halivar · · Score: 5, Funny

    "Microkernels are still better, you little punk!" With an engraving of a shaking fist.

    1. Re:His epitaph in future years: by MightyMartian · · Score: 4, Interesting

      I really miss the good old days when technical debates were over the merits and faults of such simple things as different kinds of kernels, and not about whether or not every single thing you do online is being stacked into half a dozen nation's permanent data storage facilities.

      The Linus vs. Tanenbaum dustup is from a simpler, more positive age.

      --
      The world's burning. Moped Jesus spotted on I50. Details at 11.
    2. Re:His epitaph in future years: by rubycodez · · Score: 3, Insightful

      eh, all that good old stuff is in a national permanent storage system called Usenet archives

    3. Re:His epitaph in future years: by TeknoHog · · Score: 5, Funny

      The Linus vs. Tanenbaum dustup is from a simpler, more positive age.

      It's your father's microkernel. A more elegant weapon for a more civilized age.

      --
      Escher was the first MC and Giger invented the HR department.
    4. Re:His epitaph in future years: by itzly · · Score: 2

      We can still hope he'll come to his senses before that.

    5. Re:His epitaph in future years: by Z00L00K · · Score: 2

      Both architectures have their merits. I wouldn't say that one is better than the other.

      At least Minix has come a long way since the late 80's where any crash after an uptime of more than 2 hours could be attributed to the OS instead of the application.

      --
      If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
  2. "Vrije University"? by RGuns · · Score: 4, Informative

    "Vrije" is a Dutch adjective, meaning "free". So either you write "vrije Universiteit", or you write "Free University". "Vrije University" is just silly.

    1. Re:"Vrije University"? by kruach+aum · · Score: 4, Informative

      Pretty sure it's Vrije Universiteit, because the whole functions as a name. In fact, to distinguish it from the one in Brussels, it should probably be referred to as Vrije Universiteit Amsterdam.

    2. Re:"Vrije University"? by Trepidity · · Score: 4, Funny

      But then it gets ambiguous, because someone might think you mean Free University as in no tuition, rather than Free-as-in-Freedom University. And Liberty University is already taken.

    3. Re:"Vrije University"? by gnupun · · Score: 2

      Vrije is pronounced "Fria." "Free University" and "Fria University" kinda sound the same.

    4. Re:"Vrije University"? by RyuuzakiTetsuya · · Score: 5, Funny

      Split it down the middle. GNUversity

      --
      Non impediti ratione cogitationus.
    5. Re:"Vrije University"? by rogoshen1 · · Score: 3, Funny

      Good, IPA's are way too hoppy.

    6. Re:"Vrije University"? by TheRaven64 · · Score: 2

      This is confusing in Brussels, because there is Université libre de Bruxelles (Free University of Brussels), but there is also Vrije Universiteit Brussel (Free University of Brussels), a different university.

      --
      I am TheRaven on Soylent News
  3. Aaaaahahaha ... gotta love it: by Qbertino · · Score: 4, Insightful

    "A multithreaded file system is only a performance hack. When there is only one job active, the normal case on a small PC, it buys you nothing and adds complexity to the code. On machines fast enough to support multiple users, you probably have enough buffer cache to insure a hit cache hit rate, in which case multithreading also buys you nothing." - Andy Tanenbaum on the "LINUX is obsolete" Thread from 30 Jan '92

    Nice to see a so called "expert" so far off. Seriously, not the first CS Professor to be completely backwards. I've met a few of those too. :-)

    --
    We suffer more in our imagination than in reality. - Seneca
    1. Re:Aaaaahahaha ... gotta love it: by jedidiah · · Score: 2

      No. It was not a "sensible" comment for the time. Anyone with a lick of sense could see where the tech was going and could easily realize that you had to plan for the future.

      PCs of the time were stuck in the kind of situation that Tannenbaum described not because of any inherent technical limitation but because Microsoft was a lame monopolistic sandbagger holding back the entire industry.

      Even in 1992 there wasn't that much of a gap between the capabilities of proprietary Unix hardware and PCs. Some Unix machines even ran on microprocessors used by competing home computers.

      That's why Linus created his own kernel to begin with.

      --
      A Pirate and a Puritan look the same on a balance sheet.
    2. Re:Aaaaahahaha ... gotta love it: by Megol · · Score: 4, Interesting

      In 1992, on a small PC this is true. That doesn't mean it was true for a multi-user design. Remember that for a "small PC" the disk interface was ATA without (usable) DMA support and no of the later features to lower CPU overhead - this means that a good buffer cache implementation would provide better performance not only in throughput and latency of disk accesses but also lower wasted CPU cycles proportional to the size of the cache.

      But using ATA also means that the performance of multi-threaded filesystems are unlikely to be much faster than a single threaded one, this because the bottleneck stays the same and also loads the CPU.

      A bigger PC intended as workstations (yes, there were some) would probably use SCSI instead of ATA and then the situation is a bit different. But the original quote is still true IMHO.

    3. Re:Aaaaahahaha ... gotta love it: by LWATCDR · · Score: 2

      Except he was right in 1992.
      He just underestimated the growth in speed and power of a PC. On a 386 with 4 megs of memory and a single slow hard drive he was right.

      --
      See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
    4. Re:Aaaaahahaha ... gotta love it: by Anonymous Coward · · Score: 2

      It wasn't a sensible comment for anyone who could see the writing on the wall. If you weren't in academentia, you could see that it wouldn't be long before personal computers would have more than one process active at a time.

      (Even at the time, it wasn't exactly the future. The Amiga was minor marketshare, but not obscure.)

      I think it's irrelevant, though. I still (in 2014!) think of filesystems as being primarily I/O bound. For the most part, filesystems still just wait for things and don't take a lot of CPU.

      If there's a "future" (by 1991 standards) to be seen, it's not so much "busy computers" or multi-user, but it's doing to be features like checksumming, deduplication, or maybe some nasty cases like maildirs (where something might hunt through a large inefficient data structure and takes a long time, but most things aren't like that) or maybe really fast block devices like SSDs or enormous RAID0s. The maildir example isn't really even futuristic, I'll admit. But mostly, if your filesystem is CPU-bound, then either something relatively unusual is happening, or something is broken! (In a microkernel I'd address the maildir case by having that mountpoint's filesystem be a specialist intended to deal with that particular problem (i.e. don't have an inefficient data structure, even if that means you pay some others costs). Interestingly, I think I'm sort of already doing that with Linux, maildirs being the only remaining situation where I'm still using ReiserFS.)

      Given a situation like that, whatever your multithreaded filesystem is doing, I can envision the same damn thing as a single thread in a single process that's taking a bunch of async file requests and turning them into a series of block requests forwarded to block drivers that are typically going to slowly handle them one a time, perhaps with some elevator re-ordering. And that block driver is going to be "slow" no matter what OS you're running.

      And if you do have something CPU-bound in there, it's not like microkernels can't spin off threads or launch sub-processes to do work. I'm not familiar enough with Minix to say WTF Linus was talking about there, but I bet it's a Minix problem rather than a microkernel problem.

      So what I'm saying is that by the standards of any time (whether 1991 or 2014) single-threaded filesystems are not usually bottlenecks, and in the exceptional cases where they might be (because the filesystem needs to do something CPU-bound), microkernels are not your problem. Tanenbaum was not foolish.

      I use Linux and I love its performance but even in 2014 it would take some work to persuade me that its ability to multithread within filesystems is important. I think we just happen to have some great filesystems that a lot of people have put a lot of work into. A lot more engineering goes into them now than in 1991. Just like the all the things that have changed in userspace! You don't have to be in kernelspace to take problems seriously.

      Also, Tanenbaum was right that the harder you're working your machine, the more likely you have more RAM and might get more cache hits. I'm amazed anyone would imply otherwise. "Add RAM to make things faster" is hardly a sooper-seekrit performance tip. WTF?

  4. A legend of OS design by sg_oneill · · Score: 5, Insightful

    A lot of people have the wrong impression about the good professor after the infamous exchange, but they miss that this is what academics do, and despite the flameyness of the exchange, Linus and Tanenbaum had a great deal of respect for each other. After all Linus was, for all purposes, Tanenbaums greatest student. I remember borrowing his book from UWA and getting the disks from the UWA computer club, following the instructions to get a functional minix up, then following his book to write a driver for my highly bugshit WANG (yes that was the brand name lol) hard drive controller. I learned more from that about how computers *really* work, than almost any thing I've ever learned. The difficulty of his book was notorious, probably the only books I found harder was Walter Pistons music theory book "Harmony", and Deleuzes philosophy text "Capitalism and Schizophrenia". And like those books, in its field Tanenbaums work shook the foundations of academia.

    Enjoy your retirement old man, you deserved it.

    --
    Excuse the Unicode crap in my posts. That's an apostrophe, and slashdot is busted.
    1. Re:A legend of OS design by MightyMartian · · Score: 4, Interesting

      Minix was really the first of its kind; a Unix-like OS that you could run on cheap (relatively speaking at the time) commodity hardware and that you could get the source code for. A lot of the computing we take for granted now comes from Tanenbaum's work.

      My first Minix install was on a 386-SX with a whopping 4mb of RAM I borrowed from work back in the early 1990s. I quickly abandoned Minix for Linux once it came out, but for several years I had Minix running on an old 386 laptop just for fun.

      --
      The world's burning. Moped Jesus spotted on I50. Details at 11.
    2. Re:A legend of OS design by sg_oneill · · Score: 3, Interesting

      Part of the reason I used Minix was I had an old second hand 286. because I couldn't afford one of the new-fangled 386s. Computers where bloody expensive back then! At the time I had started using a local BBS called "Omen" which had just gotten a brand spanking new ISDN connection to this new thing called "ARPAnet" (aka "Australian research something something net") , aka the australian wing of the internet, and it had two amazing features 1) IRC, 2) Usenet (There was also Gopher but eh..... Usenet was better indexed and also had hilarious flame wars). Anyway it struck me that if I had a unix I could get a SLIP connection to the internet and run IRC *and* Usenet simultaneously using the magical wonder of multitasking. Omen was using Linux (very very brand new) but since I didnt have a 386 I couldnt use it. So I grabbed Minix, since I couldnt afford Xenix or SCO Unix (Pre SCO getting brought out by Caldera and then turning cthulhu it was a great company).

      Problem is Minix didnt have a network stack :(

      --
      Excuse the Unicode crap in my posts. That's an apostrophe, and slashdot is busted.
    3. Re:A legend of OS design by McGruber · · Score: 3, Interesting

      Minix was really the first of its kind; a Unix-like OS that you could run on cheap (relatively speaking at the time) commodity hardware and that you could get the source code for. A lot of the computing we take for granted now comes from Tanenbaum's work.

      Truly!

      I first learned of Minix by reading about it in Byte magazine. At the time, I was an undergrad at a big US university, a member of the Association of American Universities. The only multitasking computers on the entire campus were a Unix mainframe, a VAX, and a cluster (lab) of Sun workstations that only graduate engineering students could have accounts on. The Unix and VAX machines could be accessed using VT-100 (and later) terminals in computer labs spread out all over the campus. There were also BYOF (Bring Your Own Floppies) computer labs filled with DOS (pre-windows) PCs, and a few labs filled with early Macs, but those labs were mostly used by humanities majors hunting-and-pecking their term papers out.

      Booting a multitasking unix-like OS on a personal computer was a huge deal back then.

  5. What I remember by Anonymous Coward · · Score: 2, Interesting

    More than Minix, I remember Tanenbaum for his "Computer Networks" textbook. Especially this:

    "The nice thing about standards is that you have so many to choose from; furthermore, if you do not like any of them, you can just wait for next year's model."

  6. Vrije University? by De+Lemming · · Score: 2

    "Vrije University" in the title sounds realy strange to me, as a native Dutch speaker. Vrije isn't a city, "Vrije Universiteit" means "Free University," which indicates it's not linked to e.g. the Catholic church. Just FYI.

  7. Does this mean the death of Minix3? by Chrisq · · Score: 2

    Does this mean the death of Minix3? That would be a shame I'd like to have seen a good open-source microkernel OS - a sort of "open source OSX".

    1. Re:Does this mean the death of Minix3? by Anonymous Coward · · Score: 4, Informative

      Despite Prof. Tanenbaum's retirement, the MINIX 3 project will continue as a volunteer-based open-source project. A major new release will be out in the Fall and will include support for the ARM processors and the BeagleBone boards. Check the Website periodically for the announcement.

    2. Re:Does this mean the death of Minix3? by plasticsquirrel · · Score: 4, Interesting

      Minix 3 will probably keep going as an open-source project, and maybe he will be even more involved?

      I feel it necessary to point out, though, that OS X is not a microkernel system comparable to Minix. OS X is largely monolithic, so if one part of the core system crashes, the whole system crashes. Minix 3 is far more ambitious because everything that is not in the (truly tiny) microkernel runs as a separate server process. For example, drivers are running in their own process, so if a driver crashes, the rest of the system can continue running.

      To manage the system, Minix has a so-called "reincarnation server" that restarts core system daemons if they go down unexpectedly. It's totally modular and redundant -- far more ambitious and advanced in its design than Linux or OS X. Minix is designed from the beginning to never go down. There is nothing else like that in the Unix world.

      This talk by Tanenbaum describes the Minix 3 design in much greater detail:

      Youtube: MINIX 3: a Modular, Self-Healing POSIX-compatible Operating System

      --
      Systemd: the PulseAudio of init systems
  8. His other project -- electoral-vote.com by MAXOMENOS · · Score: 5, Informative

    So...Dr. Tannenbaum's other project is Electoral-vote.com (2), an election prediction site (and one of the first). Any clue what's going to happen to that?

  9. A great writer by Anonymous Coward · · Score: 2, Interesting

    I own both "Operating Systems: Design and Implementation" and "Distributed Operating Systems". When I saw the retirement announcement, I cracked them open for the first time in many years to recall how much I learned from them.

    But my favorite of Tanenbaum's works is "Structured Computer Organization". I suppose it may be a bit dated, but I still recommend it to anyone who wants to know how computers work.

    1. Re:A great writer by TheRaven64 · · Score: 2

      I found Modern Operating Systems better than the Minix book. The Minix book tells you exactly how a toy OS works in detail. Kirk McKusick's Design and Implementation of the FreeBSD OS (new version due out in a month or two) tells you how a real modern OS works in detail. Modern Operating Systems gives you a high-level overview of how modern operating systems work and how they should work. If you want to learn about operating systems, I'd recommend reading the FreeBSD D&I book and Tanenbaum's Modern Operating Systems and skipping the Minix book (which was also a bit too heavy on code listings for my tastes).

      --
      I am TheRaven on Soylent News
  10. What I remember by Kohenkatz · · Score: 4, Interesting

    I'm sorry, but the best quote from that book is actually this one:

    Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway.

    In my networks class, we extended the calculation to a 747 full of DVDs (the best we could do at the time). Maybe one of these days, if I have a minute, I'll go back and do an A380 full of flash drives.

  11. Minix on Atari ST by sbaker · · Score: 3, Interesting

    I ran Minix for a year or more on my Atari ST - having a UNIX-like operating system on a machine I could have at home was a truly awesome thing. Tanenbaum's work is fascinating, useful and will be around for a good while...which is more or less the definition of "successful" in academic circles.

    The debates with Linus were interesting - but I always felt that they were arguing at cross-purposes. Linus wanted a quick implementation of something indistinguishable from "real UNIX" - Tanenbaum wanted something beautiful and elegant. Both got what they wanted - there was (and continues to be) no reason why they can't both continue to exist and be useful.

    Tanenbaum's statement that the computer would mostly be running one program at a time was clearly unreasonable for a PC - but think about phones or embedded controllers like BeagleBone and Raspberry Pi? Perhaps Minix is a better solution in those kinds of applications?

    --
    www.sjbaker.org
    1. Re:Minix on Atari ST by hansot · · Score: 2

      I ran Minix for a year or more on my Atari ST - having a UNIX-like operating system on a machine I could have at home was a truly awesome thing. Tanenbaum's work is fascinating, useful and will be around for a good while...which is more or less the definition of "successful" in academic circles.

      The debates with Linus were interesting - but I always felt that they were arguing at cross-purposes. Linus wanted a quick implementation of something indistinguishable from "real UNIX" - Tanenbaum wanted something beautiful and elegant. Both got what they wanted - there was (and continues to be) no reason why they can't both continue to exist and be useful.

      Tanenbaum's statement that the computer would mostly be running one program at a time was clearly unreasonable for a PC - but think about phones or embedded controllers like BeagleBone and Raspberry Pi? Perhaps Minix is a better solution in those kinds of applications?

      I'm still "using" Minix (currently 1.6.25) both on my ancient Atari 1040 ST and on an Atari ST simulator. Part out of nostalgia of course, but also to remind myself what you could do using a CPU that is about 10000 times slower than current CPU's, running an OS that you could actually understand completely by reading the complete source code. And I am using a cross compiler these days, based on GCC 4.x running on FreeBSD (see www.beastielabs.net/prerel.html) and it is amazing to see what you still can get to run on the 1993 vintage Minix, although there is still no networking.

      I remember having read the first edition of OSDI (including the source code) from cover to cover several times in the late 80's (the book split in two volumes as a consequence 8-) ) and a really learned a lot from it, although I was already heavily involved in Unix kernel hacking by then (both BSD and SVR4 based kernel ports). I still value Andy's OSDI in its several editions as a most educational experience.

  12. Class Act by Anonymous Coward · · Score: 5, Interesting

    I remember when Microsoft paid Ken Brown throug the Alexis de Tocqueville Institution to do a hatchet job on Linus claiming that Linux was stolen from MINIX. Now Tanenbaum, who has criticized the Linux kernel design and had some spirited exchanges with Linus, could have just said nothing and let Linus fend the FUD off by himself, but instead he stepped up and did the honorable thing by decimating Brown's arguments that Linus could have come up with the Linux kernel in just a year and his competency as a researcher/writer.

    http://www.cs.vu.nl/~ast/brown/
    http://www.cs.vu.nl/~ast/brown/rebuttal/

  13. Who gives a VUCK? by tepples · · Score: 3, Funny

    They have to use "Vrije" because it was discovered that not only is the name of "Free University Compiler Kit" obscene, but it's also misleading: the software is non-free.

  14. Remembering an early 80s Tannenbaum presentation by Anonymous Coward · · Score: 2, Interesting

    In the early 80s, I did a Unix systems startup in the UK: we were an early licensee of Unix from AT&T and sold VAXen with BSD installed and supported. DEC UK hated us. DEC US happily sold us CPUs.

    In April 1983, the European Unix User's Group (EUUG), held a conference in Bonn, Germany. The speakers included Bill Joy, Sam Leffler, Steve Bourne and Andy Tanenbaum.

    It was a hugely memorable event, including Prof. Tanenbaum's presentation. We were paying AT&T $200 or so for each Unix license. Not a huge deal for a $100,000 VAX system. But, even then, many of us could see a future where Unix or something like it would run on countless devices, including cars and washing machines. In fact, when I worked for AT&T in 1984 (yes, I know, it was "a learning experience"), I was pitching exactly that to OEMs. It was clear that something cheap or free would be required. So, back in 1983, when dinosaurs ruled the Earth, Prof. Tanenbaum gave us all the seed of a thought that free (as in beer) software could change the world.

    As an aside, his presentation was a little hard to follow, but worth the effort, because his English wasn't that great. A Dutch guy sitting next to me said that his Dutch was pretty sketchy, too. I have no means to verify this but, if true, he would join a small group of my friends and acquaintances who don't speak any (human) language well. They're all engineers :-).

    I also learned that, despite Bonn being largely flooded because of heavy rains, nothing stops a Unix conference, and that the "Geoffnet" signs I saw all over the place weren't a promotion for a new network stack, but meant "Open" in German.

  15. Remembering an early 80s Tanenbaum presentation by AlexOsadzinski · · Score: 4, Interesting

    D'oh. Accidentally posted as a Coward and misspelled Prof. Tanenbaum's name. Carry on....

    In the early 80s, I did a Unix systems startup in the UK: we were an early licensee of Unix from AT&T and sold VAXen with BSD installed and supported. DEC UK hated us. DEC US happily sold us CPUs.

    In April 1983, the European Unix User's Group (EUUG), held a conference in Bonn, Germany. The speakers included Bill Joy, Sam Leffler, Steve Bourne and Andy Tanenbaum.

    It was a hugely memorable event, including Prof. Tanenbaum's presentation. We were paying AT&T $200 or so for each Unix license. Not a huge deal for a $100,000 VAX system. But, even then, many of us could see a future where Unix or something like it would run on countless devices, including cars and washing machines. In fact, when I worked for AT&T in 1984 (yes, I know, it was "a learning experience"), I was pitching exactly that to OEMs. It was clear that something cheap or free would be required. So, back in 1983, when dinosaurs ruled the Earth, Prof. Tanenbaum gave us all the seed of a thought that free (as in beer) software could change the world.

    As an aside, his presentation was a little hard to follow, but worth the effort, because his English wasn't that great. A Dutch guy sitting next to me said that his Dutch was pretty sketchy, too. I have no means to verify this but, if true, he would join a small group of my friends and acquaintances who don't speak any (human) language well. They're all engineers :-).

    I also learned that, despite Bonn being largely flooded because of heavy rains, nothing stops a Unix conference, and that the "Geoffnet" signs I saw all over the place weren't a promotion for a new network stack, but meant "Open" in German.

  16. Tannenbaum's predictions... by RyuuzakiTetsuya · · Score: 4, Interesting

    Anyone else laugh themselves stupid at some of the predictions of the future in those posts? The idea that x86 would go away and GNU/Hurd would supplant Linux...

    Predicting the future is REALLY hard.

    --
    Non impediti ratione cogitationus.
    1. Re:Tannenbaum's predictions... by LWATCDR · · Score: 3, Insightful

      X86 has gone away. Everyone is using X86-64 and Arm. I would be more Unix like systems are ARM than X86 or X86-64.. So is AMD64 X86-64 orX86/64? I can never remember.

      --
      See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
    2. Re:Tannenbaum's predictions... by RyuuzakiTetsuya · · Score: 2

      Yeah, for mobile, but until the last 4 years, ARM really hasn't been seen as a huge thing. Relatively speaking, this is a new development. Beyond that, x86 is *still* kicking.

      Plus there's that whole bit about GNU/Hurd being the future. :)

      --
      Non impediti ratione cogitationus.
  17. I read your book! by Daniel+Hoffmann · · Score: 3, Interesting

    Really, his books are quite good, I used his the operating systems book in my undergraduate classes. I honestly found reading his book more productive than going to the classes.

  18. Re:Multi-spindle PCs are not uncommon by tepples · · Score: 3, Insightful

    What's "difficult" is finding "a computer with a single mechanical hard disk drive" that stays that way for long. Desktops tend to have internal optical drives, laptops often have an internal SSD or internal or external optical drives, and both tend to often get small SSDs plugged into them.

  19. Re:Minix download fee? by TheRaven64 · · Score: 2

    Minix has been BSD licensed for well over a decade. I'm not sure exactly how long, but it was when I was an undergrad and that was a depressingly long time ago now. As the kids today say: Old troll is old.

    --
    I am TheRaven on Soylent News
  20. His other project -- electoral-vote.com by white_owl · · Score: 2

    Not only does he use polling data to do a good job of predicting the races and the control of the US Senate/House (his track record here and a comparison of his model to Nate Silver), but he has, IMHO, excellent explanations of how the campaign managers are thinking and the likely impact of political news.

    It is surprising to me that being located in Europe that he 1) cares and 2) is so wired into the US political scene. I hope he continues.

  21. Amoeba by Jecel+Assumpcao+Jr · · Score: 2

    Interesting that he doesn't list Amoeba among his achievements. I find it far more impressive than Minix.