I’m a little unclear on differences between DMA and interrupt I/O Differences between DMA and interrupts are bogus because they are not opposing concepts. DMA and interrupts are orthogonal concepts, and both concepts are typically used together. The alternative to DMA is programmed I/O, aka PIO. The alternative to interrupts is polling. Interrupt-driven You need … Read more
This is a reprint of a blog post I did back on June 13, 2007. I’ve been using this method for quite sometime and it works great! YMMV. Who doesn’t like user-defined functions (UDFs)? If you have done any programming, chances are that you have used them extensively. The biggest problem that people have with … Read more
Rules. You create events in the system, and use rules within an event stream processor. Specifically, say you have a badge “made 10 posts”. You don’t run “select count(*) from posts where user = :user” for every post. Rather, you have a simple rule that watches each post come by, and “count them”, storing the … Read more
Let’s say you have services: MS1, MS2, MS3, MS4. The web app / mobile app hits MS1 for information. Now MS1 needs to return a response containing data that are managed by MS2, MS3 and MS4. Poor Solution – MS1 calls MS2, MS3 and MS4 to retrieve information, aggregates them and returns the final aggregated … Read more
Am I locking myself out from taking advantage of some standard if I dont’ use these? You are yourself locking out from the HTTP standard. Of course you can use GET parameters to do the same thing. It’s just not REST then, but something RPC-Like. May I suggest the book RESTful Web Services by Leonard … Read more
If you have a large array of numbers, then go with the smallest size that works. It will be more efficient to work with an array of 16 bit shorts than 32 bit ints since you get twice the cache density. The cost of any sign extension the CPU has to do to work with … Read more
I wrote the UUID generator/parser for Ruby, so I consider myself to be reasonably well-informed on the subject. There are four major UUID versions: Version 4 UUIDs are essentially just 16 bytes of randomness pulled from a cryptographically secure random number generator, with some bit-twiddling to identify the UUID version and variant. These are extremely … Read more
Software’s biggest enemy Firstly I want to iterate that Complexity and Large Code bases is the single worst enemy of software development, and that along with meeting the project requirements (i.e. deriving value from our software), managing complexity and maintaining a minimal and low friction, evolvable code-base should be at the forefront of our minds … Read more
Wikipedia: In software engineering, multi-tier architecture (often referred to as n-tier architecture) is a client-server architecture in which, the presentation, the application processing and the data management are logically separate processes. For example, an application that uses middleware to service data requests between a user and a database employs multi-tier architecture. The most widespread use … Read more