This computer came into existance as the result of a set of course notes at the University of New Brunswick (Fredricton N.B. Canada) written by L. Johnston describing a "Primitive Computer". In 1977, G. Morrison and S. Kyle, two students graduating in the class of 78 decided to construct the machine as their final project. Nearly a year in construction, the machine worked, and was successfully demonstrated running a small program.
Unlike most other homebuilt computers, this machine does NOT use a microprocessor IC - the CPU is entirely home built from TTL logic, with the highest integration components being four 74281 TTL ALUs.
Regrettably this machine is not present in my collection - in fact it is doubtful that it still exists. It remained at the university after it's creators moved on, and was last seen sitting on a shelf in the back of the engineering lab over 25 years ago - most likely it has been disposed of since then.
Click any photo to view a large high-resolution image.
Front panel of the "Primitive Computer".
Top: Address lights/switches - button resets PC to 000
Center: Data lights/switches - botton stores switch data at address.
Bottom: Power switch, Start button, Clock control and Mode switches.
Rear view of the "Primitive Computer" showing cards in installed position.
Here is a view of the chassis with front panel removed.
And some of the tools used to build it.
Here are some cards from the "Primitive Computer".
Additional card views: 1, 2, 3, 4, 5.
Here is a series of slides which were done for the final presentation.
Primitive Computer - Opening slide
Program Counter and Memory Address board - Block diagram
ALU and Memory Buffer board - Block diagram
Control Network - Block diagram
Complete Primitive Computer - Block Diagram
Program Counter and Memory Address board - Board layout
Program Counter and Memory Address board - Wiring diagram
Control Network and LED Drivers board - Board layout
Control Network and LED Drivers board - Wiring diagram
ALU and Memory Buffer board - Board layout
ALU and Memory Buffer board - Wiring diagram
Primitive Computer - Closing slide