Mark-8 Minicomputer
Rare 1974 Personal Computer
Auction Closed
July 15, 07:23 PM GMT
Estimate
10,000 - 15,000 USD
Lot Details
Description
MARK-8 MINICOMPUTER.
Jonathan A. Titus. Mark-8 Computer, consisting of 13 Printed Circuit Boards, most printed by Techniques Inc, Englewood, NJ, 1974, many of which are populated and with notation as listed below:
- CPU. Populated, including with Intel 8008 microprocessor, board numbered for placement of components
- Address Latch. Populated. Board labeled for component placement and noted as “Tested OK, 8-24-75 JRV.”
- 1K 1101 Memory – Populated. Board labeled for selected component placement and noted as “OK, 7-14-75 JRV.”
- LED Register Display – Populated. Sections labeled and noted “Bd – ok – Test 1-1-75 J.R.V.”
- Output Ports – Populated. Output pins labeled and noted “Burn In 3 hrs / Tested JRV 3-22-75.”
- Input Multiplex Board – Populated. Several areas labeled and noted “OK Test 7-12-75 29th Birthday J.R. Voight.”
- CPU. Celetron Comm Corp, 1045-C CPU. Printed by TC. Partially populated.
- Interrupt Multiplex Board. Celetron Comm Corp, 1047-C Input MUX. Printed by Nelco. Unpopulated.
- Address Latch, Celetron Comm Corp, 1046-C Address. Printed by TC. Unpopulated.
- Memory Board. Celetron Comm Corp, R-M 4K RAM 1070-C Rev A. Printed by Nelco. Unpopulated.
- Mark-8 Minicomputer Backplane, version 1.0 Geo-Mepp. Later.
- Mark-8 Minicomputer Riser Board, version 1.0 Geo-Mepp. Unpopulated. Later.
- Unidentified board printed by YLI. Unpopulated.
WITH:
Radio Electronics July 1974 featuring the Titus “Build the Mark 8 Minicomputer” feature.
Titus, Jonathan A. Computer! 1974. 48pp. With explanation, software examples, schematics, printed circuit board patterns.
AND WITH:
Intel Microcomputers, March 1974. * From CPU to Software, the 8080 Microcomputer is Here. (partial). * Molex Catalog M-400. Printed Circuit Interconnections. * New Logic Notebook, September 1974, Vol. I, No. 1. * “Techniques of Digital Troubleshooting,” Application Note 163-1. * MPS: Microprocessor Series Modules. DEC brochure. * EDN Editorial Leadership: The Computer You Hold in the Palm of Your Hand. * MiniMicroMart Mod 8 8008 Monitor 8 Manual. * MiniMicroMart, November 1975 catalogue. * Micro-8 Newsletter, December 7, 1974. Mimeographed. * Martin Research Ltd. Designing with Microprocessors? September, 1974. * MiniMicroMart Product Bulletin – A102-9/75. Featuring Mark 8A. * Microprocessor Design Series, Design News – July 22, 1974. * 2 CD-ROMs.
Receipt for Mark-8 Printed Circuit Boards from Techniques Inc. of Englewood, N.J. “Job No. Titus.” Sold to: James R. Voight of Sheboygan, WI. Ordered on 8/13/74 and shipped 9/16/74.
AT THE BIRTH OF PERSONAL COMPUTING.
Virginia Tech grad student Jonathan A. Titus’ Mark-8 was among the earliest personal computers aimed at the hobbyist market. It appeared in the July 1974 issue of Radio-Electronics as a “complete computer system of your own” – half a year before the announcement of the more widely-known MITS Altair 8800 in Popular Electronics. The Radio-Electronics feature detailed the six different modules, the computer’s capabilities – with a software example, suggested additional components and a parts list. They offered a complete instruction booklet that included schematics, build instructions and programming advice including some sample programs like a programmable function generator and even the game NIM. Titus had an arrangement with Techniques Inc. of Englewood, NJ to print the set of circuit boards and make them available for $50, but circuit board patterns were included in case the hobbyist wanted to print them themselves.
The computer was based around the Intel 8008 8-bit microprocessor - the first that was commercially available. The base unit would include 1K of RAM, expandable to 4K. Programming was limited to either assembly or machine language because of the limited memory. Titus suggested the Mark-8 would pair well with Don Lancaster’s TV Typewriter, which had appeared in the September 1973 issue of the same magazine. The alternative was to program via the Switch Register and Control Register and rely on the LED readout, which Titus admitted as more challenging. The article and booklet both included an image of a Mark-8 with a case and a printed front panel, but no plans for that were included. Consequently, no two Mark-8 computers look alike. The present example was purchased directly from Titus’s contracted supplier: Techniques Inc in September 1974 and completed by the purchaser the following year. Most boards include completion/testing date. It seems that they were never built into a case. The group also contains 4 boards by Celetron Comm, an identified board printed by YLI and a modern backplane and riser board for the Mark-8.
Very few original Mark-8s are known to exist - likely due to the difficulty of the project and surely as a consequence of the MITS Altair 8800 appearing in the January 1975 issue of Popular Electronics. The Altair was a more fully-realized hobbyist computer that could be purchased in both kit and completed forms and included the more powerful Intel 8080 microprocessor. We know of only one other example of the Mark-8 that has appeared at auction.