AIX - AIX is IBM's Unix implementation, which it develops for a number of its products, notably the IBM SP series. Other manufacturers, such as Motorola, also produce hardware that runs AIX. AIX incorporates elements of System V, BSD, and OSF/1, but includes enough unique features to make using, and especially administering, AIX somewhat different from working with other Unix implementations. Nevertheless, recent versions are compliant with most Unix standards.
IRIX - IRIX is a Unix implementation by Silicon Graphics. Though it incorporates its own extensions, IRIX is strongly System V-based and compliant to most Unix standards.