[cctalk] Altair 8800 question
I have a reproduction of the metal nameplate strip that looks very close to the original if you want one. $10 plus shipping. Mike D
[cctalk] Re: Current Loop Schematics
If it’s specifically to interface to a model 33 Teletype, here’s a design that works well and is pretty simple. https://altairclone.com/teletype.html Mike
Re: 8" disk drive questions...
Here’s a demo video of a Pertec 5.25” drive that has dual index sensors so you can simply flip a standard disk over and use both sides: https://www.youtube.com/watch?v=8UCcONLTsuQ=32s Mike
Re: Mystery 1702A(?) EPROM Programmer
It might be the Mikra-D MD-2040 1702 programmer. Similar to the MD-2044 on my website but a parallel data interface (e.g., manual switches and lights) instead of a serial RS-232 interface. The 2040 is briefly mentioned in the .pdf file here: https://deramp.com/downloads/eprom_p...kra-d/md-2044/ Mike
Re: CWVG
I can archive your disk content if you end up needing some assistance. I have a few Vector Graphic machines with 100tpi Micropolis and Tandon 100-4M drives as well as Mod-I drives at 48tpi. I also have utilities to archive and recreate disks on these drives by exchanging the disk image with a PC via XMODEM (FLOP2PC and PC2FLOP). Note that these disk images can also be mounted and run under SIMH. Mike
Re: michael Holley?
...and SWTPC.ORG is gone again. Mike
Re: WTB: CompuPro / Godbout RAM 17
Were you the winner of the eBay auction? It went for a very reasonable price. It was very difficult for me to not bid on it - those are great boards for use with early S100 systems :) Mike
Re: WTB: CompuPro / Godbout RAM 17
I assume you saw the RAM 17 on eBay right now? Mike
Re: Floppy pressure pad replacement?
I’ve got some adhesive backed industrial felt that I punch with a leather punch. I’ve replaced many of those pads on 8” and 5.25” drives and the felt pad works well. Shoot me an email and I can send you a few pads if you need. Mike
Re: michael Holley?
Sorry, I did not see your post that there was no concern of losing Michael’s SWTPC content. I simply did not want to see more great material disappear from the internet as our peers age and become unable to maintain their web presence. I’ve seen that happen over and over now. I’ll remove my mirror of Michael’s SWTPC content. You can contact Michael Evenson and let him know his assistance in preserving the content for the benefit of the hobby community is also “unauthorized.” I presently pay for 150Gb of bandwidth on deramp.com to host material for vintage computing hobbyists. I’m surprised the swtpc.org bandwidth requirements are high enough to be an issue that requires your “grace” to allow us to view its content. Mike
Re: michael Holley?
I archived the entire website in the summer of 2019, shortly before it went offline in the Fall of 2019. When it became clear that SWTPC.COM was not coming back on line, I chose to host the content at https://deramp.com/swtpc.com/ so hobbyists could still have access to the excellent material Michael pulled together. Mike Evenson also hosts a copy of the website at http://www.swtpcemu.com/mholley/. Anything you can do to preserve and host the material at swtpc.* is much appreciated! Mike
Re: windows program to read papertape from reader through serial port
I’ve used Teraterm to receive and save binary paper tapes and ASCII paper tapes to files using the log function without any problem. When you say receive “into an ASCII file,” what is the ASCII requirement you’re trying to satisfy? What is on the tape - text or binary data? Mike
SWTPC 6800, FLEX and Percom Floppy
Now that I have my SWTPC 6800 loading and saving programs with paper tape, cassette, and floppy disk (using the Percom LFD-400 controller and their MiniDOS and MPX “operating systems”), the next logical step is getting FLEX up and running. Unfortunately, I only have the Percom floppy controller and I don’t know if FLEX compatible disk drivers and boot code were ever written for it. Before I go create Percom support for FLEX from scratch, does anyone have any leads? Mike
Re: Parasitic Engineering Altair Clock Fix Kit...
I scanned my Parasitic clock mod documents and put them at the link below. https://deramp.com/downloads/altair/hardware/altair_8800_computer/Parasitic%20Clock%20Mod.pdf Mike
Re: Parasitic Engineering Altair Clock Fix Kit...
I scanned my Parasitic clock mod documents and put them at the link below. https://deramp.com/downloads/altair/hardware/altair_8800_computer/Parasitic%20Clock%20Mod.pdf Mike On Thursday, February 20, 2020, 09:29:09 PM CST, Mike Douglas wrote: I have an original paper manual for it. I’ll try to get it scanned tomorrow. Mike
Re: Parasitic Engineering Altair Clock Fix Kit...
I have an original paper manual for it. I’ll try to get it scanned tomorrow. Mike
Re: SWTPC 6800 and Percom Floppy Controller
I have typed in the assembly source for couple of the missing utilities for which I was looking (there are a few listings in the LFD-400 manual), so I now have a pretty complete and useful Percom disk system for the SWTPC 6800. I also wrote FLOP2PC and PC2FLOP utilities to archive a disk to a PC and to write a disk from an archived image saved on a PC. The disk images are transferred over a serial port using the XMODEM protocol. If anyone ever runs across one of these Percom disk controllers in the future, feel free to contact me. Mike > On Jan 7, 2020, at 6:44 PM, Mike Douglas wrote: > > 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
Re: SWTPC 6800 and Percom Floppy Controller
I’ve been able to complete the system running under the MiniDisk+ PROMs and added several programs like BASIC and an assembler to the disk. It all works together, but operations don’t integrate with each other very well. With much thanks to Bill Sudbrink, I also obtained the source to Percom’s MPX PROM so I was able to create a system running under MPX. Bill also had several of the programs (in S19 format) that would have been distributed with MPX, so I’ve got a pretty representative Percom MPX system up and running now. This setup, in turn, is pretty darn slick and well integrated for its day. It’s a lot like a Northstar DOS system, but a bootable disk is not required to get started since the OS is in PROM. Add the fact that the standard SWTPC configuration with MIKBUG or SWTBUG made it simple to get programs into RAM via the serial port (e.g., S19 records from papertape, cassette, or today - a PC) and it’s easy to build up a disk from scratch. I’d still like to flesh this system out a bit more, so if anyone has any Percom disks or software archived in any format on a PC, let me know, thanks! Mike > On Jan 7, 2020, at 6:44 PM, Mike Douglas wrote: > > 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
Re: SWTPC 6800 and Percom Floppy Controller
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 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 To: cctalk@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
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
