keeping simple

Author: vy

  • Fischer Lynch Patterson and timeouts

    There is a widely cited (over 1400 cites in CiteseerX ) result called the Fischer-Lynch-Patterson theorem about consensus – a key issue in distributed databases or any system where data is either distributed or replicated or both. In this paper, we show the surprising result that no completely asynchronous consensus protocol can tolerate even a single…

  • Why is clock synchronization so important in big data

    Distributed transactions have historically been implemented by the database community in the manner pioneered by the architects of System R* [22] in the 1980s. The primary mechanism by which System R*-style distributed transactions impede throughput and extend latency is the requirement of an agreement protocol between all participating machines at commit time to ensure atomicity and durability. To ensure isolation,…

  • Patents considered harmful, by some.

    @vyodaiken This makes no sense. You don’t foster competition by handing out monopolies. — Timothy B. Lee (@binarybits) September 16, 2014 That’s not how it looks from here but I think part of the muddiness in the software patent argument is the result of arguments that really attack the entire idea of patents but are…

  • A claimed validated operating system.

    The claim: we have demonstrated the comprehensive formal verification of the seL4 microkernel, with a complete proof chain from precise, formal statements of high-level security and safety properties to the  binary executable code. GD The L4 base is useful –  we advocated a similar approach with RTLinux which was, um, very similar to L4. It…

  • Cassandra

    Cassandra is quite interesting – and time sync seems increasingly critical to correct operation. Here are some resources: A paper on the storage model from developers at Facebook. A reasonably clear introduction from IBM Developer Works. A big difficulty for people who are, like me, more familiar with the relational databases is that Cassandra and…

  • A hard theorem becomes easy over time.

    The basic result of the incompleteness proofs is pretty simple.  The proofs are complicated because the idea was literally unthinkable until programming was invented. The heroic efforts of Gödel, Skolem, Post, and Church to create a mathematics in which doing mathematics could be represented as some sort of calculation were an incredible feat of imagination. But…

  • From Jersey to Wall Street – or the equivalent

    A common configuration for FSMLabs TimeKeeper customers is to cross-couple time sources in New Jersey and New York City or London and Slough or Chicago and Aurora or Singapore and Sidney- any two trading locations that are connected with high quality network. Sometimes the network connection does not even have to be that great. TimeKeeper will…

  • Real-time Linux

    My opinion has always been that the Linux-RT project was based on an unfixable engineering error.   A few words on the status and the future of RT: ———————————————– The situation since last years RTLWS (https://lwn.net/Articles/572740/) has not improved at all, it’s worse than before. While shortly after RTLWS quite some people promised to whip…

  • The Horrors of Software Patents

    US Patent Number  4701722 A is a perfect example of everything software patent opponents hate about software patents: It implements  mathematical functions that are pretty well known. It covers a process of changing information not changing any physical object one could touch. It is owned by a company with a business model depending on licensing…

  • The technology disconnect

    What it did was reinforce a point about the sociology of management: From cars to space shuttles, from offshore oil wells to nuclear reactors, the people who make the decisions are often out of step with the mechanical details.” – Mathew Wald, New York Times. 2014/06/09. We sell pretty complex software that synchronizes clocks of computers, down…