AlpineR writes: "Ars Technica has posted a long technical review of the architectural changes in Snow Leopard. File compression smuggles extra data into HFS+ files to speed I/O. The operating system is now almost entirely 64-bit and encourages developers to come along. Quicktime is being updated piecemeal into a modern, 64-bit video system with Quicktime X. LLVM and Clang offer two fast and flexible alternatives to compilation with GCC. Blocks bring dynamic programming features like for_each() to C-based languages. Grand Central Dispatch makes it easy to launch the right number of threads for the available hardware and encourages parallelization of code. OpenCL makes intensive processing portable to the CPU, GPU, or dedicated accelerators. The article also inspects the graphical changes in Snow Leopard and minor new features of the Dock, Finder, and system dialogs."