IRIX is a computer operating system developed by Silicon Graphics, Inc. (SGI) to run natively on their 32- and 64-bit MIPS architecture workstations and servers. Based on UNIX System V with BSD extensions, it is capable of extremely long uptimes, and its XFS file system is regarded as one of the most advanced journaling file systems in the industry. IRIX 3.x was based on UNIX System V Release 3 with 4.3BSD enhancements, and incorporated the 4Sight windowing system, based on NeWS and IRIS GL. SGI's own Extent File System (EFS) replaced the System V filesystem.