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InterSystems was the computers brand name of the Ithaca company which previously manufactured various cards for other mainframe makers.

The DPS-1 is based on the S-100 bus. It seems to be a copy of the Altair 8800 and Cromemco Z-1 systems. The case had a 20-card capacity and can support 8 and 16 bit processors.

With a 16-bit Zilog Z8000 processor, the system could take up to 256 KB of RAM and run the Unix operating system, as well as the more usual CP/M.
It was the last computer proposing a front panel with switches and data/addresses LED.


Mark Mullin specifies:
There were actually two boxes as I recall, one holding the computer and the other holding great big nasty heavy quantum hard disks (20Mb each) - you could actually have more than one drive. The OS it ran was Coherent, a Unix 7 clone from Mark Williams in Chicago.

It was one of the first machines you could get and reliably and affordably run your own UNIX server - one thing that I do recall was that they'd built their own memory management unit on a S-100 card that attached to the cpu over an additional top bus - the card used static high speed ram to hold the segmentation mapping data, and the chips themselves had a nasty habit of walking out of their sockets every month or so - when the system started crashing a lot more than normal, you pulled out the mmu card and reseated all of the chips.

Steven Sorensen adds:
They made 2 styles of with a front panel, and one without. Later they came out with a cache-bios for their version of CPM, it became a real hot rod. Motherboards were by Godbout I believe. Early CPU boards were a little flakey at 4 MHz, but later cpu boards were great! I replaced the crystal section on the CPU board with a 6 MHz oscillator and Z80b CPU.

We need more info about this computer ! If you designed, used, or have more info about this system, please send us pictures or anything you might find useful.



In my post below, I didn''t finish a sentence.

The company I worked for sold Ithaca Intersystems computers with the usual trusty Televideo terminals, with the monochrome monitors.

Friday 18th August 2017
Loretta M. (California, USA)

Interesting that the guy who started the company added a comment!

In about 1980 or so I went to work for a small computer sales and service company in Oklahoma as the Service Manager. We sold Ithaca Intersystems computers to small businesses and court reporters$ most of our customers had two 8-inch floppy drives and ran C/PM (I think?). Some had Z-80A processors, and later the CPU cards had Z-80B CPUs which could utilize more RAM. Software was the Peachtree accounting software and Wordstar. To copy a file or create a directory, you had to use a program called "PIP" (Peripheral Interface Protocol or something like that), I seem to remember, instead of just a cp command. I had this fabulous system with the front lights and switches. The ones our customers got were plain looking. Wish I could remember more about the models. I can still see the S-100 bus, and those cards sitting into it, though.

There were the usual Televideo monochrome monitor

Besides the Intersystems sales and support, my assistant and I maintained all the ScanData cash register systems for Hardee''s restaurants in the state. Oh, that could be a nightmare.

Those big old 8-inch floppy drives with the Intersystems had to be realigned and serviced every few months, or the stepper motor and head would be unable to read previously formatted floppies! That was a pain in the rear, taking a loaner drive to a customer, making sure it could read their disks, then dragging their drive housing back to the company to use an oscilloscope and special alignment disk to tune it up. It was a mess if their disks couldn''t be read, but none of my customers ever lost their data. I remember how exciting it was when we got the first Winchester (I think) hard drive. Wish I could remember its capacity!

The company I worked for also sold Diablo daisy wheel printers, the 620 and 630 models, to go with the Intersystems computer. Those things were workhorses! The court reporters printed so much stuff on the Disaperf perforated continuous paper that they pounded the heck out of those 630s and they just kept on printing. I think I soldered hundreds of RS-232 connectors, making printer cables for those printers. Pin 2 was transmit, I think, pin 3 was receive, and pin 7 (or 20?) was ground. In those days, purchased computer cables were too expensive, and/or didn''t work with your system, so you had to make a custom one, anyway.

One of the people at Intersystems told me that Carl Sagan used an Ithaca Intersystems computer and Wordstar to write Cosmos.

Later our company went broke due to mismanagement by the CEO and Sales Manager, and I bought one of the systems and ran my own word processing business for awhile, and also serviced the computers for the previous customers for a few years on the side, til they got new IBM PCs. Wish I had kept that computer, the first one I owned.

Friday 18th August 2017
Loretta M. (California, USA)

Anyone interesting in knowing more about Intersystems and the DPS-1 feel free to contact me. I starting the company.

Steve Edelman

Friday 20th July 2012
Steven Edelman (USA)


MANUFACTURER  Intersystems
TYPE  Professional Computer
YEAR  1979
KEYBOARD  Depending on the video terminal used
CPU  Z80, Z8000, 8080, 8086
SPEED  4 Mhz
RAM  8 KB up to 256 KB
ROM  2 KB (Monitor)
TEXT MODES  Usually 80x25 terminal
SIZE / WEIGHT  Unknown
I/O PORTS  2 x Serial RS232, 1 x Parallel
BUILT IN MEDIA  Various FDD and HDD configurations
OS  CP/M, Unix
POWER SUPPLY  Built-in Power Supply Unit
PERIPHERALS  All of the S-100 cards and associated peripherals
PRICE  About $7200 for a typical system (64 K, 2x600 KB disks, Printer, video terminal)

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