Greg, Thanks for the response. The article you reference is also the one bit of documentation I was able to find. It's been a big help. I have been in contact with Bob and recently picked up one of his RAM/EPROM boards to use while I get the system restored. Mike On Wednesday, January 8, 2020, 2:29:32 PM CST, Gregory Beat <w9gb at icloud.com> wrote: Mike - Cer-Comp5566 Ricochet AvenueLas Vegas, NV 89110(702) 452-0632William E. Vergona wrote firmware on those two (2), 2708 ROMs.He later (1980s) worked with Tandy (Coco-3) Color Computer products.==?68 Journal, May 1980 (Back to Future, 40 years later)MiniDisk+ DOS , Pages 11 - 13http://www.swtpcemu.com/swtpc/68MJArchive/V02N05_May1980.pdf Have you contacted Bob Applegate (Corsham Tech)?https://www.corshamtech.com/ss-50-faqs/He might be aware of source from his SS-50 clients and contacts. Bob reopened his business (Corsham) three weeks ago, for a period of time.I did not see him at VCF Midwest, due to his health issues.https://www.corshamtech.com/back-in-business-for-now/ GregChicago==From: Mike Douglas <deramp5113 at yahoo.com> To:?cctalk at classiccmp.org Subject: SWTPC 6800 and Percom Floppy Controller I?m restoring a SWTPC 6800 that includes the Percom LFD-400 floppy controller. This controller goes on the SS-50 bus instead of the SS-30 bus where the SWTPC controllers installed. The standard Percom MiniDOS PROM is installed, and the other two PROM sockets have a third party extension called ?Minidisk+?. This was made by a company called Cer-Comp. These PROMs are instead of Percom?s own ?MiniDOS PlusX (MPX) PROM.? I?ve got the system working, and I can use Minidisk+ to save and load files, but I know I?m missing some nuances of command parameters. I don?t have any sort of documentation for Minidisk+, so before I go figure it out by disassembling the PROMs, does anyone have any sort of documentation for Minidisk+ by Cer-Comp for the Percom LFD-400 floppy disk controller? Also, I?d like to burn the MPX PROM as an option. Does anyone have the MPX PROM or the source code for MiniDOS PlusX? Mike