SCP 8086 Monitor

Tim Paterson wrote an 8086 monitor/debugger ROM for the SCP Gazelle in 1979 and used it to boot 86-DOS (or any other operating system that would run on the Gazelle). It eventually morphed into the 86-DOS/MS-DOS/PC-DOS DEBUG utility. I did some searches to find all versions of the SCP 8086 Monitor ROM that still exist today.

Versions 1.4 to 1.6 are 2K in size and intended for the CPU Support Board model 300, while version 1.9 is 4K in size and intended for the CPU Support Board model 301. Booting from hard drive is only supported by version 1.9.

Download

Version	Revision	Source Code	Cromemco 4FDC	Cromemco 16FDC	NorthStar SD	SCP Disk Master	Tarbell DD	Tarbell SD
1.4	1980-02-18	ASM	BIN/HEX	N/A	BIN/HEX	N/A	BIN/HEX
1.5	1980-04-24	ASM	BIN/HEX		BIN/HEX		BIN/HEX
	1981-05-26	ASM	BIN/HEX		BIN/HEX		BIN/HEX
	1982-03-19	ASM	BIN/HEX	BIN/HEX	BIN/HEX	BIN/HEX	BIN/HEX	BIN/HEX
	1982-06-10	ASM	BIN/HEX	BIN/HEX	BIN/HEX	BIN/HEX	BIN/HEX	BIN/HEX
1.6	1982-??-??	ASM*	N/A			BIN/HEX	BIN/HEX	N/A
1.9	1983-08-04	ASM	N/A			BIN/HEX	BIN/HEX	N/A

*Reconstructed based on existing binary.

Manuals

1.4 - from Tim Paterson (archived)
1.5 (alt) - very common version
1.6 update - appears to be an addendum to 1.5 manual
1.9 - possibly the last version

Page written by Yufeng Gao. Last updated: 2026/03/15.