High Quality Content by WIKIPEDIA articles! HP-UX (Hewlett Packard UniX) is Hewlett-Packard's proprietary implementation of the UNIX operating system, based on System V (initially System III). It runs on the HP 9000 PA-RISC-based range of processors and HP Integrity Intel's Itanium-based systems, and was also available for later Apollo/Domain systems. Earlier versions also ran on the HP 9000 Series 200, 300, and 400 computer systems based on the Motorola 68000 series of processors, as well as the HP 9000 Series 500 computers based on HP's proprietary FOCUS processor architecture. HP-UX was the first Unix to offer access control lists for file access permissions as an alternative to the standard Unix permissions system. HP-UX was also among the first Unix systems to include a built-in logical volume manager. HP has had a long partnership with Veritas Software, and uses VxFS as the primary file system. HP-UX 11i is currently cre