keeping simple

Category: Uncategorized

  • sequential and combinational state machines

    There’s a correspondence between the notions of “combinational” and “sequential” in digital circuit engineering and some structure in state machines (and therefore monoids)  that seems interesting. In digital logic, a “combinational” circuit like a logic gate has can be associated with a time T so that the output depends only on input signals applied over…

  • Linux descends into priority inheritance hell

    The PI chain walk is implemented by the function rt_mutex_adjust_prio_chain. The implementation has gone through several iterations, and has ended up with what we believe is the best. It walks the PI chain by only grabbing at most two locks at a time, and is very efficient. The rt_mutex_adjust_prio_chain can be used either to boost…

  • State machines and circuits

    The cross coupled latch is one of the greatest inventions of the 20th century State machine models of timing and circuit design

  • Public spirit of programmers

    It’s sad to note that while Doctors/engineers/journalists/even-lawyers without borders are all organizations of people who help less developed nations, “programmers/software/etc” without borders refers to outsourcing.

  • Fake Steve Jobs: “Then I hung up”

    I stopped, then. There was nothing on the line. Silence. I said, Randall? He goes, Yeah, I’m here. I said, Does any of that make sense? He says, Yeah, but we’re still not going to do it. See, when you run the numbers what you find is that we’re actually better off running a shitty…

  • Recursive transducers and products – pre-submit version

    Recursive transducers.

  • Software Design and time synchronization

    I have a blog post up at fsmlabs.com about our TimeKeeper software for time synchronization. TimeKeeper is currently aimed at financial trading markets, but we also hope to market it to electric power  distribution and transmission engineers who have a similar need for precise time synchronization within substations and for instrumentation. There are also applications…

  • Montavista thoughts

    Bill “Linux Pundit” Weinberg explains: Business Model and Execution:  Many MontaVista watchers have argued that the company’s business model was essentially flawed. […]  Such a model based on building with and for open source can devolve into less attractive high-overhead packaged service business in the face of a rising value line. […] The model did…

  • Process Algebra and classical automata

    The long awaited process algebra paper is now finally available in PDF Reducing Process Algebra.

  • Primitive recursion and transducers

    11/23/2009 please see the updated version: here. Yet another version of the recursion/transducer paper . The main result is that simultaneous primitive recursion on strings corresponds to general products of state machines. Primitive recursion on strings is analogous to primitive recursion on integers where we define f(0,x) = g(x) and f(n+1,x) = h(f(n,x),x). In strings the…