keeping simple

Author: yodaiken

  • Proving Operating Systems Correct:#8

    One of the longstanding problems with operating systems is that there is no way to validate their correctness in the same way that engineers can calculate the ability of a beam to carry a weight or a wire to carry a current. Well, the problem is worse than that, because we don’t even have a…

  • The romance of trade and fuzzy slippers

    Commerce used to be more fashionable. The French historian Fernand Braudel writes that in the 1630s “ten ships a year from the Indian ocean, from Calicut, Surat, or Msulipatam, and the odd Portugese ship out of Goa were still arriving in Mocha with cargoes of pepper, cinnamon, nutmeg, and cloves“. He quotes a French trader…

  • Spyware and Security

    So an exec from Claria (formerly known as Gator) heads off to the US Government’s . department of Homeland Security. As of today, if you Google “claria spyware” you get 44000 hits. The commercial (and governmental) utility of building security holes into software should never be overlooked. Security holes in software are a combinations of…

  • RTLinux easy but RT hard.

    I wrote a chapter for an academic book recently and the publisher sent me a “copyright assignment” form ( don’t even start) that asked me, among other things, to provide a warranty that it was perfectly safe to use the methods I described. Well, to be plain – it’s not. Real-time software gives you a…

  • Embedded productivity and engineering skills

    I was at some trade show wandering around with a cynic who was pointing out that every booth advertised productivity improvements. How many improvements we’ve made to productivity, and this has gone on for years” he said,“By now, we must be able to make incredible things with no effort.” In the embedded world, productivity is,…

  • Synchronization blues

    Synchronization is hard in real-time applications, but not as hard as people imagine. If you follow a few simple rules you can make it manageable. Never force priority and mutual exclusion to fight each other. You can’t mean “Task A is more important than TaskB” and “TaskB should be able to lock TaskA out of…

  • Class and lack thereof

    From the always readable Joel on Software: Attention, FogBugz competitors: a court has ruled that you are welcome to continue to advertise your products when people search for FogBugz on Google. I actually don’t think there’s anything wrong with this although it does show a certain lack of class, mm, don’t you think? You don’t…

  • Soft real-time and software costs

    Imagine designing an automobile with a motor that runs really well on a demonstration frame, with none of those heavy panels or safety devices, and only tested on a short flat track. Imagine an engineering team designing an automobile or truck deciding that since high torque is only needed rarely, they don’t have to worry…

  • What is software security for

    The natural tendency of an engineer is to assume that “security” is an engineering issue that reduces to a type of reliability. And the Common Criteria security document outlines a solid engineering approach (written in astoundingly opaque bureaucratese) for assuring software is designed, developed, and tested to limit security failures. But “software security” means different…