Via reddit, we find this article about implementing zig zag in assembly. See zig zag figure in section 1.6.6 of this article for more info. The author implemented the interlaced version of zigzag (16bit word elements) as it was not already available. This version is for more recent processors as can be seen by this quote.Furthermore, as should be clear by th […]

Link to article.I like what they did with the routing. I wonder how it works at the low level. They have 24 dual core IA32 processing units arranged in tiles. There is a 2D grid routing system. From what I gather, there is a buffer for incoming data (and outgoing?) and each L2 cache is independent. There is a central (up to) 64GB of RAM.I like the buffering […]

If you only watch CNN, MSNBC, CBS, ABC, BBC or CBC for your news, you probably didn't hear about one of the biggest scientific, economic and global scandals ever. I'm a big fan of conspiracy theories for their entertainment values, but this has real consequences. Still, it does have a lot of comedic value in some parts. Specifically, the coding par […]

I don't know if this is possible, but it'd be cool if it was. In Project V, I use a generic list with the objective that no operation takes more than O(log n). However, it has one drawback which causes it to be just short of that objective. Before going into that, a description of the list is required.I will simplify the scenario since Project V ha […]

Back to the Future: Lisp as a Base for a Statistical Computing System by Ross Ihaka and Duncan Temple Lang, and the accompanying slides. This paper was previously discussed on comp.lang.lisp, but apparently not covered on LtU before. The application of cutting-edge statistical methodology is limited by the capabilities of the systems in which it is implement […]

Michi Henning, Why API Design Matters, Communications of the ACM, May 2009. After more than 25 years as a software engineer, I still find myself underestimating the time it takes to complete a particular programming task. Sometimes, the resulting schedule slip is caused by my own shortcomings: as I dig into a problem, I simply discover it is a lot more diffi […]

ActorScript(TM): Industrial strength integration of local and nonlocal concurrency for Client-cloud Computing by Carl Hewitt, 2009. ActorScript is based on a mathematical model of computation that treats “Actors” as the universal primitives of concurrent digital computation [Hewitt, Bishop, and Steiger 1973; Hewitt 1977]. Actors been used both as a framework […]

Can code ever be too terse? The designer of the K and Q languages discusses this question and many more with Queue editorial board member Bryan Cantrill.

While often breaking the rules of traditional language design, the growing ecosystem of purpose-built "little" langages is an essential part of systems development.

Traditional computer science deals with the computation of correct results. Realtime systems interact with the physical world, so they have a second correctness criterion: they have to compute the correct result within a bounded amount of time. Simply building functionally correct software is hard enough. When timing is added to the requirements, the cost an […]

There are characteristics of good coding that transcend all programming languages. Programmers have debated the merits of different programming languages since the dawn of programming. Every coder has a favorite general-purpose programming language, and many have an unfavorite language, too. If the coder is old enough, often that unfavorite language is Fortr […]