HP MPE (Multiprogramming Executive) is Hewlett-Packard’s classic operating system designed for the HP 3000 minicomputer line. Introduced in the 1970s, it offered robust multiuser, multitasking capabilities and strong reliability for business environments. MPE evolved into MPE/iX, incorporating POSIX compliance, improved networking, and disk management features. Known for its stability and long lifecycle, it powered enterprise applications in finance, manufacturing, and government. Even after official support ended, MPE remains used in legacy systems due to its durability and proven performance.