MCM Key-Cassette drawing
Dublin Core
Title
MCM Key-Cassette drawing
Subject
computer hardware: design drawing
Description
Historical context (by Z. Stachniak)
In April, 1972, Intel Corp. of Santa Clara, California, announced its first 8-bit microprocessor — the 8008. In just a few months, the prototypes of the first general purpose computers powered by the 8008 chip were already working on site at the French company Réalisations et Études Électroniques located in the suburbs of Paris and at Micro Computer Machines (MCM) with headquarters situated on the outskirts of Toronto. These firms fully recognized, articulated, and acted upon the immense potential of the budding microprocessor technology for the development of a new generation of cost effective computing systems. However, it was MCM which built the first microprocessor-based computer designed specifically for personal use — the MCM/70, the first PC.
MCM built several prototypes of the MCM/70 before the computer's manufacturing began in mid-1974. All of them have their roots in the Key-Cassette concept developed by the company's co-founder and first president Mers Kutt. A drawing of it can be found in design notes that Kutt kept from late 1971 until mid 1974. It is among the oldest preserved sketches of a microcomputer to be manufactured specifically for personal use. The name `Key-Cassette' most likely derives from `Key-Edit' — the name of the key-edit system that was manufactured by Kutt's former company — Consolidated Computer Inc.
The one-page sketch created in early 1972 depicts a case in the style of a typical desk-top calculator of that time with built-in keyboard, one-line display, cassette storage, and acoustic coupler with built-in modem for communication over phone lines. In addition, the Key-Cassette was to be programmed in the APL language. The Key-Cassette concept already expressed several key aspects of personal computing philosophy that MCM would be shaping in the coming years: that of an individual-focused complete computing environment, easy to learn and interact with.
The annotated drawing provides enough information to grasp the basic operations of the Key-Cassette. The small 32-key keyboard of the Key-Cassette would allow the user to enter all the alphanumeric and numeric characters as well as the APL and special function symbols. To achieve such a degree of compactness, each key was designed to enter up to 5 symbols (using a combination of key strokes). The symbols on keycaps would be color coded to distinguish between the symbols that can be entered directly (red symbols in the center of keycaps) and those that can be entered via a combination of key strokes (black symbols placed in the corners of keycaps).
The one line display of the Key-Cassette would allow the user to view a single line of APL code, a computer output, or an error message. Using the rotate keys `→' and `←' the displayed information could be scrolled left and right to fully reveal its contents. Using the roll keys `↓' and `↑', one would scroll through the lines of APL code. The sketch of the Key-Cassette is augmented with two drawings of possible segmented display elements: one comprised of 13 display segments and the other of 15 segments. Finally, the tape cassette drives were to provide external storage.
There was no physical prototype of the Key-Cassette concept.
Recommended readings:
In April, 1972, Intel Corp. of Santa Clara, California, announced its first 8-bit microprocessor — the 8008. In just a few months, the prototypes of the first general purpose computers powered by the 8008 chip were already working on site at the French company Réalisations et Études Électroniques located in the suburbs of Paris and at Micro Computer Machines (MCM) with headquarters situated on the outskirts of Toronto. These firms fully recognized, articulated, and acted upon the immense potential of the budding microprocessor technology for the development of a new generation of cost effective computing systems. However, it was MCM which built the first microprocessor-based computer designed specifically for personal use — the MCM/70, the first PC.
MCM built several prototypes of the MCM/70 before the computer's manufacturing began in mid-1974. All of them have their roots in the Key-Cassette concept developed by the company's co-founder and first president Mers Kutt. A drawing of it can be found in design notes that Kutt kept from late 1971 until mid 1974. It is among the oldest preserved sketches of a microcomputer to be manufactured specifically for personal use. The name `Key-Cassette' most likely derives from `Key-Edit' — the name of the key-edit system that was manufactured by Kutt's former company — Consolidated Computer Inc.
The one-page sketch created in early 1972 depicts a case in the style of a typical desk-top calculator of that time with built-in keyboard, one-line display, cassette storage, and acoustic coupler with built-in modem for communication over phone lines. In addition, the Key-Cassette was to be programmed in the APL language. The Key-Cassette concept already expressed several key aspects of personal computing philosophy that MCM would be shaping in the coming years: that of an individual-focused complete computing environment, easy to learn and interact with.
The annotated drawing provides enough information to grasp the basic operations of the Key-Cassette. The small 32-key keyboard of the Key-Cassette would allow the user to enter all the alphanumeric and numeric characters as well as the APL and special function symbols. To achieve such a degree of compactness, each key was designed to enter up to 5 symbols (using a combination of key strokes). The symbols on keycaps would be color coded to distinguish between the symbols that can be entered directly (red symbols in the center of keycaps) and those that can be entered via a combination of key strokes (black symbols placed in the corners of keycaps).
The one line display of the Key-Cassette would allow the user to view a single line of APL code, a computer output, or an error message. Using the rotate keys `→' and `←' the displayed information could be scrolled left and right to fully reveal its contents. Using the roll keys `↓' and `↑', one would scroll through the lines of APL code. The sketch of the Key-Cassette is augmented with two drawings of possible segmented display elements: one comprised of 13 display segments and the other of 15 segments. Finally, the tape cassette drives were to provide external storage.
There was no physical prototype of the Key-Cassette concept.
Recommended readings:
- Stachniak, Z. Inventing the PC: the MCM/70 Story , McGill-Queen's University Press (2011).
- Stachniak, Z. Learning from Prototypes, IEEE Annals of the History of Computing, vol. 42, no. 2 (2020), pp. 63-71.
- Stachniak, Z. The MCM/70 Computer, CORE, the Computer History Museum, Fall 2003.
Creator
Mers Kutt
Date
1972
Relation
Micro Computer Machines collection
Format
digital image of a drawing, black and white images
Coverage
Ontario, 1972
Files
Collection
Citation
Mers Kutt, “MCM Key-Cassette drawing,” York University Computer Museum Canada, accessed December 24, 2024, https://museum.eecs.yorku.ca/items/show/277.