S-100 SD Systems

This page last updated July 31 2022. Contents (c) copyright Herb Johnson 2022, except content produced by others who choose to retain copyrights.

S D Sales manuals are listed in my miscelaneous S-100 page under "SD Sales". This page is for S D Systems.

For S-100 SD Systems information, software and hardware, check the following:
SD Systems documentation available
Other SD Systems VF II related files
PROM 100 code from Andrew Lynch
....and the links below.

In 2012 I moved the Versafloppy II material to another Web page, links are included below.
SD System Versafloppy II cards and information are available
SD System motherboards available
my floppy drives and diskettes section.
tech specifications on floppy drives and media
Bruce Jones' work on the VF II
John Monahan's SD Systems work
Other's work on the VF II
commentary and code by Fred Scipione and Chuck Guzis
8080 code by Denver Hull
8080 code by Kevin Sisson
updates & comments by Jon Chapman
updates & comments by Roger Hanscom

To email me or to order follow this link.
To return to my S-100 home page click here.

SD Systems Versafloppy II S-100 floppy disk controller

SD System Versafloppy II cards and information are available at the linked Web page.

PROM 100 code

SD Systems PROM-100 is a 2708 and 2716 EPROM programmer. The following code ASM files are courtesy of Andrew Lynch, but also available from SIG/M volume 73:
PROM16a.asm is nondiskette based code for 2716's
PROM16u.asm is CP/M code for 2716's
PROM08a.asm is nondiskette based code for 2708's
PROM08u.asm is CP/M code for 2708's
macro3_lib.asm are macros for the above


Robert Coward was kind enough to dump and disassemble SD Systems ZBUG in Dec 2018. It's described in the SD Systems Z80 Starter System manual. Since ZBUG works with a hex display and keyboard, you'll likely need this manual to make best use of the code.

Other SD Systems related files

SDSOURCE ZIP SD Systems SBC-200 dissassemblies of various sorts. From "Curt" ?
BIOS, ROM monitors, some format code. May be incomplete.
SDHEX ZIP SD System ROM dumps in hex
disassemblies and assemblies Herb Johnson has done. Some 8080 to Z80 translation tools, assembler and disassembler tools too.
RAMDISK ZIP Jade RAMDISK code for SD Systems, Jade "Double D" floppy controller.
HARD ZIP SD Systems hard disk executables
more Versafloppy II software is on my VF II Web page.

Note: Any ".CPM" files are actually CP/M .COM files.


I have some SD Systems SDOS disks, but they are 8-inch and I'll have to read them off someday. SDOS was SD System's rewrite of CP/M.

SD Systems documentation

Here's the SD Systems docs I have available. Contact me to obtain a copy.

Versafloppy I disk controller, with 33 pgs of BIOS and diagnostic source code, total 85 pgs.

Versafloppy II disk controller rev C Copied 2 pages per 8 X 11 sheet (half size)
manual with schematics only, 30 sheets (60 pgs)
w/1795 docs, add 12 sheets (24 pgs)
see above for source code, S-100 card, and more information.

Other manuals:
Expandoram User's manual, 30 pgs
PROM-100 rev c, with source code listings, 90 pgs (mostly code)
SDOS manual, 100 pgs
SD Monitor USer manual, (SBC-100) 23 pgs or SBC-100 & 200, 18 pges (copy)
Text Editor, Z80 Global Assembler, Linker, 50 pgs
SBC-200, 50 pgs
SD Systems Microcomputer Operating Manual, 35 pgs
ExpandoRAM II, with notes, 60 pgs
VDB-8024, with source code, 70 pgs
ExpandoRAM III, 32 pgs
I/O 8 serial, with driver source for RTC, 55 pgs
MPC-4 (smart serial controller), 100 pgs
OEM Price list, Aug 1983, 2 pages
2-page product descriptions for: IO/8, SBC 300, VFW-III, ExpandoRAM IV
Z80 Starter Kit, 115 pages (copy)
COSMOS or Communications Oriented Multi-User OS V2.17, 94 pages (copy)
...multi user OS, CP/M programs, for SBC-200 and Expandoram II
upgrade rev D ExpandoRAM II to 256KB; and errata, 14 pgs (copy)

Herb Johnson
New Jersey, USA
follow this link to email @ me

Copyright © 2022 Herb Johnson