The 64-bit Unix operating system for HP's AlphaServers. Formerly Digital Unix when Alpha was a product family from Digital Equipment Corporation, it was renamed Tru64 Unix in 1999 by Compaq (HP acquired Compaq in 2002). HP had developed a transition kit to migrate Tru64 Unix users to HP-UX on Itanium servers and stated that the best features of Tru64 Unix were included in HP-UX. See
Alpha.