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Sunday, July 20, 2014

Vintage Computer MARK 8 - 40 year Anniversary July 2014 - Start of something Big

David Larsen KK4WW
Bugbooks 
MARK8 Microcomputer is 40 years old this month.

The MARK 8 microcomputer designed by Jon Titus and published as a construction article in RadioElectronics magazine July 1974.  The MARK 8 was the first construction article about how to build your own microcomputer and was an important part of the home / personal computer revolution.

  A big Congratulations to Jon for this 40 year anniversary.


Bugbook Historical Microcomputer Museum
MARK 8 Computer by Jon Titus 
Dr. John Titus designed and published a construction article about the MARK 8 Computer in the July 1974 'Radio Electronics Magazine'. Dr. Titus  was a graduate student at Virginia Tech and is given credit for being the first to make it possible for an electronic hobbyist to build their very own microcomputer.   Several were even made into rather complex control computers.  We have one in our Microcomputer Museum with lots of extra complex circuits and software to make it into a process control computer. Hobbyist had to obtain all the parts on his own.  A company did make the bare printed circuit cards available and the additional parts were a challenge acquire. This limited the number of computers constructed to several hundred or less. To help a 48 page construction guide was made available by the publishers of ’Radio Electronics' for about $5.00.  Only a few MARK 8 microcomputers were ever built into working computers and less the 50 original are in collections / Museums today.

Comments by John Titus
40 years ago this July--Radio-Electronics magazine published the "Mark-8 Minicomputer" article written by Jonathan Titus as a construction project for people who might want their own computer. The Radio-Electronics cover showed the Mark-8 as Jon built it while a graduate student at Virginia Tech.

"I just wanted my own computer," said Titus. "As a teenager I built a lot of circuits with 24-volt relays and created a brute-force design for a 4-bit binary adder. I didn't know anything about logic or gates, so I just stuck it out until I had a circuit that worked. It took a lot of relays and 6-pole switches! Later I took some classes on digital-logic integrated circuits and created some projects of my own. Don Lancaster's articles in Popular Electronics provided a lot of inspiration and good ideas. Later in grad school I got to use PDP-8/L minicomputers and realized how cool they were and decided to build my own computer. About then, Intel announced its 4004 microprocessor, which could have worked, but I waited for the 8-bit 8008 and jumped in. Intel provided a complicated design for a computer board, so I took it and adapted that design so my computer had a front panel of LEDs and switches. The home-computer era had arrived."

"People have asked how I chose the name 'Mark-8,'" continued Titus. "Larry Steckler, the editor at Radio-Electronics wanted a name for the computer project, so on the spur of the moment I decided on Mark-8. I used the word 'minicomputer' because many people knew small computers such as the PDP-8, Nova, and others. I didn't think 'microcomputer' would appeal to people and no one thought about a 'personal computer.'"
Jon donated the original Mark-8 Minicomputer to the Smithsonian Institution in the 1980s and it became part
of the long-running "Information Age" exhibit.

The publication of the MARK 8 computer in the July issue of 'Radio Electronics' was the  first time a construction article was available on how to build your own microcomputer. This was noticed by the competing publication 'Popular Electronics' and followed in January 1975 with an article about the "MITS Altair 8800" microcomputer.  John was first with the MARK 8 and as a result many computer clubs and newsletters were started to help computer hobbyist build and use the MARK 8.

Here is a the whole article in 'Radio Electronics' from  Rich Cini Collector of Classic Computers web site.

Here is a look at five very different variations of how folks constructed their MARK 8 computer. 

David Larsen KK4WW


It is my pleasure to be a colleague of Jon and have worked together in the "Blackburg Group" for about 12 years.

 "by David Larsen" KK4WW Microcomputer Collector/Historian.