The MCM/70 was a pioneering microcomputer first built in 1973 and released the next year, making it one of the first microcomputers in the world, the second to be shipped in completed form, the first portable computer, and arguably the first truly usable microcomputer system.[1] Nevertheless this machine remains virtually unknown.
Contents |
The MCM/70 was the product of Micro Computer Machines, one of three related companies set up in Toronto in 1971 by Mers Kutt. Kutt had already started another firm, Consolidated Computer Inc., to produce a data-entry system known as "Key-Edit".[2] Kutt had worked at Queen's University in Kingston, Ontario during the late 1960s where he saw the frustration of computer users who were forced to submit programs in punched card form to a shared mainframe. Key-Edit was a low-cost terminal with a single line of display intended to address this need. However, he had been squeezed out of the company and was looking for new projects.
Kutt decided his next venture would be a machine intended to support programming in the APL programming language, then the "new thing" in computer science. APL was best programmed using a custom keyboard which were in very short supply, so a low-cost terminal similar to the Key-Edit would be a sought-after product. His design, the "Key-Cassette", would be similar in design and concept to the earlier Key-Edit, but offer complete editing capability and support for two cassette decks or one cassette and an acoustic coupler modem to upload programs to other machines.[2]
In order to keep down costs, the original design was intended to look as much as possible like a desktop electronic calculator, Kutt's notes of the era state they should "Try and use existing calculator cover, display, modify power supply, and replace keyboard." The replacement keyboard was a small model with 32 keys, not a full typewriter system, and each key was used to enter up to five different characters. The display consisted of either 13 or 15 segmented LEDs.[2]
Kutt knew Bob Noyce personally, and had been following Intel's work on what was then known as the 1201, an 8-bit microprocessor soon renamed as the Intel 8008 and slated for release in late 1971. Incorporating on 28 December 1971, Kutt Systems signed an agreement the same day with Intel to supply an Intel 4004, a SIM4- 01 development system, supporting chips from the MCS-4 chipset, and an MP7-01 EPROM programmer to be delivered to Kutt at no charge. Kutt was intending to work with the 8008, but these were delayed until spring, so the 4004 system would be used for early work.[2]
In April 1973, only weeks before the release of the 8008, Kutt visited Intel and discussed the 8008's progress with Bob Noyce and Hank Smith. The next month, they received one of the earliest SIM8-01 kits and they started work on what was now known as the "M/C", for "microcomputer". In the time between designing the Key-Cassette and receiving the SIM8, the design had expanded considerably. It now supported a complete keyboard, a "chiclet" design similar to the ones used on early models of the Commodore PET, and greatly improved the display with the addition of the Burroughs Self-Scan 32-character display.[2] The system would not only allow entry of APL programs, but run them locally.
After experiments with the "unusable" SIM8, the company decided to build their own motherboard from scratch. This included the Omniport on the back, an 8008-expansion bus. Meanwhile, work on porting an APL interpreter to the system continued in parallel, using an 8008 emulator written in Fortran known as "INTERP/8". The system, mocked up in breadboard form, was first displayed publicly on 11 November 1972 at the Kutt offices in Kingston, Ontario.[3] In May 1973, the same system was shown at the APL Users’ Conference in Toronto, now encased in fibreglass.[4] The completed design, in its new injection moulded case, was demonstrated for the press on 25 September 1973.[5]
The machine consisted of a wedge-shaped metal box about half a metre on the side, with a keyboard at the front, a cassette tape recorder(s) in the middle, and a tiny one-line plasma display at the top. The MCM/70 looks quite a bit like a Commodore PET with the monitor removed and replaced with the smaller display.
APL was built in, and the machine included a battery that automatically saved the "workspace" when it was turned off. The MCM/70 weighed 20 pounds (9 kg) and shipped in a number of versions with various amounts of RAM and zero, one or two cassette drives. The basic unit, model 720 with an 80 kHz 8008, 2 kB RAM and no cassette drive sold for $4,950 Canadian (at the time the dollar was about par to the US dollar). The "fully loaded" 782 with 8k and two drives was $9,800, and was the only model that really sold.
At the time, the machine was already officially being referred to as a "personal computer". The first manuals contain a personal note from Kutt to future customers, "But the simplicity of the MCM/70 and its associated computer language…make personal computer use and ownership a reality… Enjoy the privilege of having your own personal computer."[6] The first complete systems were shipped to dealers in the autumn of 1974.
The machine received only minor recognition, so in 1975 it was re-released with no changes as the MCM/700. Also released that year was a punched card reader, plotter and a number of programs. The MCM/800 followed in 1976 which was faster, included 16k RAM, and included the ability to drive an external monitor. Virtual memory was supported on all of the machines, although using cassettes for storage made it somewhat impractical.
1978s MCM/900 was faster yet, included 24 kB RAM, and added a monitor as a standard option. The MCM/1000, aka MCM Power was a re-packaged /900, and was later re-packaged again as the MCM MicroPower. The new design was to be the basis of future models, including the considerably different "next generation" A*2. The real change for the /900 and /1000 was to support the HDS-10 disk server, which included an 8.4 MB 8 inch Shugart hard drive, an 8 inch floppy disk drive, and a 64 k Zilog Z80 to control it. Up to 8 /900's /1000's could be plugged into the HDS-10.
MCM found that the Canadian business market was unprepared to risk venture capital on the computer market, which they did not understand. By the late 1970s MCM was facing a number of advanced home computer systems with the same sort of power as their own machines, and the funding needed to make competitive machines was not available. The company was shut down in 1982 or 83.
Rights to the A*2 design were sold to Ampex. They worked on the design for about a year before also shutting down development.