Pascal MicroEngine is a series of microcomputer products manufactured by Western Digital from 1979 through the mid-1980s, designed specifically to run the UCSD p-System efficiently.
The sole configuration known to be still running in 2018 and documented on the web is described by Marcus Wigan[5] and contains 312 kB of memory, RAM disc support through a modified Z80 BIOS (written by Tom Evans) taking advantage of the memory mapping chip on the Z80 board, and using the UCSD Pascal III version of the operating system tuned specifically for the WD chipset - once the Microengine had booted the ram-disc was available.
The performance of this Microengine on a series of simply Interface Age benchmarks (originally designed for BASIC programs) is documented in an Australian Computer Society, MICSIG, paper presented at the National Conference on Microcomputer Software, Canberra, ACT presented in June 1982,[6][7] along with a wide range of other contemporary machines and compilers, including Z80 systems supported by the 9511 APU chip hosted in the Digicomp S-100 Microengine system that he used.
Fast compilation made the MicroEngine especially nice as a developer's machine, and the inclusion of a semaphore primitive in the microcode was particularly useful for multi user enhancements, which were developed in Melbourne for the Canberra Australia-based Ortex Company, extended to be a multiuser system and often sold with a bundled pharmacy management system, also delivered on the Sage IV computers under UCSD Pascal IV and enabled as a multiuser system using the Sage multiuser BIOS rather than by extending UCSD Pascal IV to add a semaphore.
This performance advantage was eroded by the later availability of p-code to native machine code translators, and mainstream 16-bit microprocessors such as the Intel 8086 and Motorola 68000.
[8] John Lloyd of the University of Melbourne created an early version of his Prolog for this system and both Basic and Fortran 77 compilers were ported from other UCSD P-system implementations at various times, but not widely distributed.