keeping simple

Category: systems

  • operating systems are harder than quantum physics

    Went to hear Tilak Agerwala talk on the “Future of Data Centers” and was struck again by the way in which system developers and chip architects find solving problems like quantum power leakage and manufacturing devices with 100 angstrom feature sizes to be easier than improving operating system performance or design. Seymour Cray used to…

  • clouds versus pcs

    George Gilder had an article in Wired on data centers as clouds. My instinct is to dismiss anything Gilder writes because of his track record of wacky ideas (e.g. feminism is destroying civilization and supply side economics makes sense). But, in this article, Gilder reports on some smart people. The sheer massive use of electrical…

  • linux kernel

    From LinuxDevices Every Linux kernel is being developed by nearly 1,000 developers, working for more than 100 corporations. An average of 3,621 lines of code are added to the kernel tree every day. A new kernel is released approximately every 2.7 months. Since 2005, the kernel has grown at a steady pace of 10 percent…

  • Sorcerers apprentice at ATT: Security and privacy and reliability collide again

    AT&T considers reading all the packets that cross its lines. Quite an interesting proposal. Tim Wu’s take The prospect of AT&T, already accused of spying on our telephone calls, now scanning every e-mail and download for outlawed content is way too totalitarian for my tastes. But the bizarre twist is that the proposal is such…

  • what do we got to verify in an os?

    From comments below. Just one more comment: I think we should make a distinction between a tool that can verify threaded code and a tool that can verify the code that implements threading. The latter is what you are looking for here and it is much more difficult. Furthermore it is arguably unnecessary — a…

  • Happy new year and validation

    Updated below! Years ago I proposed the following code snippet as a minimal standard for a useful verification method. Still not quite there. /* you are not expected to understand this */ if(save()){ load_memory_management(); /* map in new current */ return; }else { current = new; resume(); panic(“RESUME RETURNED! KERNEL BROKENn”); } Not so complicated,…

  • Cell phone handsets and linux and software value

    Update at the end. Two FSMLabs alumni are leading the charge for Linux handsets in two different companies. Jason Whitmire is now GM of cell phones for Wind River. Jason’s blog is here and a Linuxdevices article discusses his first post which concerns the, well, machinations of Google and the two big cell-phone consortia Limo…

  • formal methods considered harmful and more on soft real-time

    [fixed a couple of typos, Dec. 20 2007] John Regehr writes: On the other hand, there is plenty of useful work to be done on supporting time sensitive applications (I’ll just avoid saying “soft real-time”) even when no guarantees are made. Let’s take the example of an OS that disables interrupts when any process is…

  • Soft real-time and QOS (revised)

    [ revised version of an older post] “Soft real-time” is a perfect example of the “soft design” noted in an earlier post. There are perfectly good ways of characterizing quality of service (QOS) assurances precisely. Doug Jenson proposes one possible definition: The general case of a deadline (which is a soft deadline) has utility measured…

  • Sparc T2 (niagra 2)

    UT architecture seminar today was by Greg Grohoski from Sun – an updated version of his Hot Chips talk. I’m not a big fan of this approach to chip architecture: 8 processors, each with 8 threads, but they are working hard on a real problem. The problem is the usual one of high speed processors…