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Links for 2014-09-17

  • Texas Judge References ‘The Big Lebowski’

    “The First Amendment of the U.S. Constitution is similarly suspicious of prior restraints,” wrote Justice Lehrmann in the decision highlighting a cornerstone that has “been reaffirmed time and again by the Supreme Court, this Court, Texas courts of appeals, legal treatises, and even popular culture.” That last reference to popular culture contained an interesting footnote citing none other than Walter Sobchak, a character in [‘The Big Lebowski’].

    (tags: lebowski movies coen-brothers prior-restraint law supreme-court walter-sobchak funny)

  • on using JSON as a config file format

    Ben Hughes on twitter: “JSON is fine for config files, if you don’t want to comment your config file. Which is a way of saying, it isn’t fine for config files.”

    (tags: ben-hughes funny json file-formats config-files configuration software coding)

  • Understanding weak isolation is a serious problem

    Peter Bailis complaining about the horrors of modern transactional databases and their unserializability, which noone seems to be paying attention to: ‘As you’re probably aware, there’s an ongoing and often lively debate between transactional adherents and more recent “NoSQL” upstarts about related issues of usability, data corruption, and performance. But, in contrast, many of these transactional inherents and the research community as a whole have effectively ignored weak isolation — even in a single server setting and despite the fact that literally millions of businesses today depend on weak isolation and that many of these isolation levels have been around for almost three decades.’ ‘Despite the ubiquity of weak isolation, I haven’t found a database architect, researcher, or user who’s been able to offer an explanation of when, and, probably more importantly, why isolation models such as Read Committed are sufficient for correct execution. It’s reasonably well known that these weak isolation models represent “ACID in practice,” but I don’t think we have any real understanding of how so many applications are seemingly (!?) okay running under them. (If you haven’t seen these models before, they’re a little weird. For example, Read Committed isolation generally prevents users from reading uncommitted or non-final writes but allows a number of bad things to happen, like lost updates during concurrent read-modify-write operations. Why is this apparently okay for many applications?)’

    (tags: acid consistency databases peter-bailis transactional corruption serializability isolation reliability)

  • “Left-Right: A Concurrency Control Technique with Wait-Free Population Oblivious Reads” [pdf]

    ‘In this paper, we describe a generic concurrency control technique with Blocking write operations and Wait-Free Population Oblivious read operations, which we named the Left-Right technique. It is of particular interest for real-time applications with dedicated Reader threads, due to its wait-free property that gives strong latency guarantees and, in addition, there is no need for automatic Garbage Collection. The Left-Right pattern can be applied to any data structure, allowing concurrent access to it similarly to a Reader-Writer lock, but in a non-blocking manner for reads. We present several variations of the Left-Right technique, with different versioning mechanisms and state machines. In addition, we constructed an optimistic approach that can reduce synchronization for reads.’ See also http://concurrencyfreaks.blogspot.ie/2013/12/left-right-concurrency-control.html for java implementation code.

    (tags: left-right concurrency multithreading wait-free blocking realtime gc latency reader-writer locking synchronization java)

  • Russell91/sshrc

    ‘bring your .bashrc, .vimrc, etc. with you when you ssh’. A really nice implementation of this idea (much nicer than my own version!)

    (tags: hacks productivity ssh remote shell sh bash via:johnke home-directory unix)

  • Troubleshooting Production JVMs with jcmd

    remotely trigger GCs, finalization, heap dumps etc. Handy

    (tags: jvm jcmd debugging ops java gc heap troubleshooting)

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