Sun Enterprise is a range of UNIX server computers produced by Sun Microsystems from 1996 to 2001. The line was launched as the Sun Ultra Enterprise series; the Ultra prefix was dropped around 1998. These systems were based on the 64-bit UltraSPARC microprocessor architecture and related to the contemporary Ultra series of computer workstations. Like the Ultra series, they ran Solaris. Various models, from single-processor entry-level servers to large high-end multiprocessor servers were produced. The Enterprise brand was phased out in favor of the Sun Fire model line from 2001 onwards.