the United States Postal Service. SGI's servers powered an artificial intelligence program to mechanically read, tag and sort the mail (hand-written and block) at a number of USPS's key mail centers. The rise of cheap yet powerful commodity workstations running Linux, Windows and Mac OS X, and the availability of diverse professional software for them, effectively pushed SGI out of the visual effects industry in all but the most niche markets. High-end server market SGI continued to enhance its line of servers (including some supercomputers) based on the SN architecture. SN, for Scalable Node, is a technology developed by SGI in the mid-1990s that uses cache-coherent non-uniform memory access (cc-NUMA). In an SN system, processors, memory, and a bus- and memory-controller are coupled together into an entity called a node, usually on a single circuit board. Nodes are connected by a high-speed interconnect called NUMAlink (originally marketed as CrayLink). There is no internal bus, and instead access between processors, memory, and I/O devices is done through a switched fabric of links and routers. Thanks to the cache coherence of the distributed shared memory, SN systems scale along several axes at once: as CPU count increases, so does memory capacity, I/O capacity, and system bisection bandwidth. This allows the combined memory of all the nodes to be accessed under a single OS image using standard shared-memory synchronization methods. This makes an SN system far easier to program and able to achieve higher sustained-to-peak performance than non-cache-coherent systems like conventional clusters or massively parallel computers which require applications code to be written (or re-written) to do explicit message-passing communication between their nodes. The first SN system, known as SN-0, was released in 1996 under the product name Origin 2000. Based on the MIPS R10000 processor, it scaled from 2 to 128 processors and a smaller version, the Origin 200 (SN-00), scaled from 1 to 4. Later enhancements enabled systems of as large as 512 processors. The second generation system, originally called SN-1 but later SN-MIPS, was released in July 2000, as the Origin 3000. It scaled from 4 to 512 processors, and 1,024-processor configurations were delivered by special order to some customers. A smaller, less scalable implementation followed, called Origin 300. In November 2002, SGI announced a repackaging of its SN system, under the name Origin 3900. It quadrupled the processor area density of the SN-MIPS system, from 32 up to 128