Pascal MicroEngine

From Wikipedia, the free encyclopedia

The Pascal MicroEngine was a series of products manufactured by Western Digital from 1979 through the mid 1980s, designed specifically to efficiently run the UCSD p-System. Whereas other microcomputers ran a machine-language p-code interpreter, the Pascal Microengine had its interpreter implemented in microcode, so p-code was effectively its native machine language.

As usual on the p-System, the most common programming language used was Pascal.

One of the first validated Ada compilers (MicroAda™) was developed on and for the MicroEngine; this was the only other programming language available. A(da replaced A(ssemble on the main command menu, as no native assembler was available or needed. Due to limited memory (62K 16-bit words, the last 2K words being reserved for memory mapped input/output and PROM for the harddisk boot code) only very small Ada programs could be compiled. At one point in the compilation the compiler swapped the operating system out to disk, to gain just a little more room.

The MicroEngine ran a special release III p-System, which was not used on any other platforms. However, the enhancements of release III were incorporated into release IV which was made available for other platforms but not for the MicroEngine.

The MicroEngine series of products was offered at various levels of integration:

WD-9000 five chip microprocessor chip set
WD-900 single board computer
WD-90 packaged system
SB-1600 Modular MicroEngine single board computer
ME-1600 Modular MicroEngine packaged system

The MicroEngine chipset was based on the MCP-1600 chipset which formed the basis of the DEC LSI-11 low-end minicomputer and the WD16 processor used by AlphaMicro (each using different microcode).

The MicroEngine was only modestly successful; its performance advantage was quickly eroded by the increasing popularity of mainstream 16-bit microprocessors such as the Intel 8086 and Motorola 68000, and by the availability of p-code to native machine code translators.

One example of a commercial product based on the MicroEngine was the AVAB Viking lighting control system, which used the Modular MicroEngine boards along with some custom hardware.