ATing system> The version of Unix running on Hewlett-PackardworkstATions. HP-UX conforms to X/Open' s Portability Guide Issue 4 (XPG4), Federal InformATion Processing SpecificATion (FIPS) 151.1, POSIX 1003.1, POSIX 1003.2, AT&T' s System V Interface Definition 2 (SVID 2). HP-UX incorporATes selected feATures from the University of California AT Berkeley Software Distribution 4.3 (4.3BSD). It is known by some as "HP-SUX". [FeATures?] (1997-05-12)