Perpendiculous

A few days ago I was chatting with some friends, and the topic of caching came up. I mentioned MESI, which is the basis for modern multicore cache coherence (There are variants like MOESI and MERSI, but the general idea is the same).  It then occurred to me that I’ve never actually made a test to see the effects of MESI in action. (more…)

NX, or the No eXecute bit, is an interesting technology that prevents instructions on the stack from getting executed.  The reason for this is security (stack smashing becomes a bit more difficult for a would-be attacker), and the implications are typically few and far between. (more…)

(apologies in advance — this will be a rather technical post.  It’s eventually intended for fdiv.net, but while it’s getting migrated I figured I’d plop it down here.)

Instance Variables (or, more briefly, ivars) are a pretty simple trend in Object Oriented Languages.  They’re data that get carried along inside an object, helping to define its state.  While it would be fun to elaborate more on this, this particular article isn’t intended to teach the basics of OOP.  So if you’re unsure of what an ivar is, this article probably isn’t for you. (more…)

A lot of lists have popped up where I frequent (digitally, at least) lately.  Intended schedules, self-diagnostics, recipes, time-lapse accomplishments, etc.  You know the drill.  At one point in the not-so-distant past, I was probably pretty good maintaining such things as well.  I suppose I need to refine my time management skills (or lack thereof) to keep things fresh. (more…)

From time to time I accumulate cute little hacks that help debug/reverse engineer stuff in Objective-C. Typically, these are gdb macros that help introspect data from within a live program, though sometimes it’s a blob of ObjC code that does something fun when injected into the runtime. Today, I’ve discovered something extraordinarily helpful that falls into neither of those categories. (more…)