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Tag Archives: threads

When to use NSOperation vs. GCD

Mac OS X has a number of concurrency mechanisms, and that increases with Snow Leopard. In addition to run loops, threads (both Cocoa and POSIX) and operations, Snow Leopard adds **Grand Central Dispatch** (GCD), a very lightweight way to represent units of work and the style of concurrency they need, and have the system figure […]

Cooperative User Threads vs. Preemptive Kernel Threads

James Robertson, Cooperative Threading: > Well, in Cincom Smalltalk, this model gives you predictability – > you know exactly what a thread is going to do. The issue with runaway > threads rarely comes up for a simple reason – most processes end up > pausing for I/O (user input, db access, file access, sockets […]