Ron Ward's S-100 systems

The following S-100 story is from Ron Ward, from March 2009. See other stories of S-100 owners on this Web page, part of my S-100 Web site. The Web page for Ithaca systems is this Ithaca Web page. Most recent revision dated March 03 2009. My edits are in []'s. - Herb Johnson

Hi Herb:

Iím a previous customer. On January 22, 2007 I purchased several Ithaca Intersystems manuals from you. They were just what I needed. Thanks.

The Ithaca InterSystems hardware is [still] working. I also have two Sugart 851 8" Floppy disk drives that are known to be good and are ready to go.

However, I need an Ithaca InterSystems CP/M Distribution Disk or one with all of the CP/M programs that were modified by Ithaca InterSystems. These are:


[Note: I had some older Ithaca CP/M stuff, but not this version. - Herb]

Right now the DSP-1 is being used for generating and testing true random numbers that are being generated by a radioactive source (Americium 241) and a Geiger counter (AN/PDR-27S). The program resides in 2716 EPROM's on a Cromemco 32K Bytesaver. I have wire-wrapped a 1MEG high speed static RAM board. Not hard to do with modern 512K X 8 32 pin DIP RAM chips!

I want to get Ithaca's version of CP/M operating on this very nice computer. If you find someone that has Ithaca's version of CP/M for its series II systems, I would be very interested in obtaining a copy of it!!

I was [also] looking for either a Series II VIO board IA-1190 or a 6SIO board IA-3030, because the standard Ithaca Intersystems BIOS is set-up for them. I have all of the parts needed to wirewrap a Series II VIO board. If one is not available, I will just wirewrap one. Maybe someday I will find one. I am just waiting to see if an I/O board is available before I start wirewraping one.

[Note: I provided the 6SIO board. - Herb.] Before I use it in my system I will write some simple utility & diagnostic programs to make absolutely certain that the Floppy Disk Controller is OK! I have a Gould K100D logic analyzer and a Tektronix 7834 oscilloscope to work with. I just wanted you to know that I'm not some guy with just a logic probe.

[In addition] I am bringing up [Processor Technology's] ALS8 on a mostly homebrew (wire-wrapped) computer. The memory, Serial & Parallel IO, Cassette IO, and VDM1 clone were wire-wrapped by me in 1976-1977 while I was in college. The power supply Transformer was from a PERTEC nine track tape drive. The motherboard is from IMS. It uses a Cromemco MPU Z80 CPU card. By restoring this system I will have a vintage cassette based computer, otherwise all of this would just be junk. This system cost me about 1/4 of the cost of an IMSAI with purchased cards in 1976-1977.

All of these things are over 30 years OLD!

I just discovered that one of the five 2716's on my wirewrap memory board that held Processor Technology's ALS8 tape cassette based development system is bad. Also, My VDM1 clone is acting flakey (jittery horizontal sync). It is most likely just a bad wirewrap joint or an IC. It worked fine for many years and shouldn't take much to get it up and running. Tomorrow I will send an order to Jameco Electronics for several 2716's.

I just found the problem with the VDM1 board. It was an oxidized wirewrap socket. It is working fine now.

I would like to know which vintage computer you like to use the most. Mine is a DEC PDP-11/83. I'm running RT-11 V5.5 and have the original DEC Distribution disks that came with the computer.

- Ron Ward

Contact information:

Herb Johnson
New Jersey, USA
To email @ me, see see my ordering Web page.

Copyright © 2009 Herb Johnson and Marcus Lewis