keeping simple

Category: systems

  • The multics file system

    The design proposed in this paper is ubiquitous. A file is simply an ordered sequence of elements, where an element could be a machine word, a character, or a bit, depending upon the implementation. A user may create, modify or delete files only through the use of the file system. At the level of the…

  • Fukushima Robot Blog

    This from the IEEE is really fascinating. It is the blog of a robot operator in the Fukushima nuclear plants. Some interesting things about controls, robot handling, and durability are discussed. And, big surprise, the competence of the organization that created the disaster in the first place seems less than stunning.

  • Why computers are more and more devices for generating heat from electricity

    Why is it that the hardware interfaces of disk drives 30 years ago were simple and clear and they currently require enormously elaborate drivers? Imagine if one could provide a command consisting of (read/write, diskaddress, buffer_address, count, notification_address) so that the disk drive controller wrote a completion code in the notification_address when done.  Would that…

  • Dutch masters

    Seen on Linux Weekly News. Ext4 maintainer Ted Ts’o has responded with a rare (for the kernel community) admission that technical concerns are not the sole driver of feature-merging decisions: It’s something I do worry about; and I do share your concern. At the same time, the reality is that we are a little like the…

  • Industrial robots state of the art

    During the BP Macondo leak I was struck by the enormous level of skill needed by the robot submarine operators and wondered at the apparently low level of automation available to them. But the absence of robotic equipment in the TEPCO Fukushima Daiichi facility is really even more comprehensive and more puzzling – there’s no mile…

  • Security news

    The lesson of this story is that even (particularly?) computer security companies cannot put up with the inconvenience of standard security precautions. Greg Hoglund’s nightmare began on Super Bowl Sunday. On Feb. 6 the high-tech entrepreneur was sitting in his home office, trying to get to the bottom of some unusual traffic he was seeing…

  • Airbus computer and electrical problems

    Whoops! From Aviation Week According to a bulletin issued by the U.K. Air Accidents Investigation Branch (AAIB), an electrical fault led to a series of display and control problems. These included the intermittent failure of both pilots’ electronic displays and the uncommanded application of left rudder trim.  [..] The crew also reported hearing “chattering” from…

  • why microkernels don’t work

    You can almost just see it from this diagram of connected boxes.  I want to think of the whole system as a series of connected state machines.  The arrows show how information is moved around the system with the green arrows identifying paths that carry data to and from the memory. When you fill in…

  • Shocking advances in Operating Systems

    And here I was complaining about the lack of progress in OS development “This will blow away any RTOS,” said Cauchy. “We speed up execution by doing things like vector interrupts, I/O memory mapping, and turning off timers.” By Gad!

  • Processor architecture

    I wish that processor architecture was not so committed to a obsolete model of software. For example, it has become clear over the last few years that the sloppy shared memory thread model of programming has multiple drawbacks. Sharing of data, in particular, should be tightly controlled. Yet processor architectures are “optimized” for unstructured sharing…