Although it was manufactured for only a few years, it is generally agreed that the Altair 8800 was the computer that kicked off the PC age.
While working in the weapons laboratory at Kirtland Air Force Base, Ed Roberts and Forrest Mims began producing kits for model rocket hobbyists. Along with Stan Cagle and Robert Zaller, Roberts and Mims established Micro Instrumentation and Telemetry Systems (MITS) in 1969, producing radio transmitters, calculators, and instruments for model rockets from Roberts' garage in Albuquerque, New Mexico. As sales grew, and their inventory of products increased, MITS moved to a larger building in Albuquerque in 1973.
In late 1974, learning that MITS was working on a microcomputer, the editor of Radio-Electronics asked if they could get a completed prototype together in time for the 1975 publication of its popular January issue. The prototype was finished and shipped to the magazine, but it did not arrive on time. The computer featured on the cover was an empty box with switches and LEDs on the front panel and didn't resemble the actual computer.
As MIT had the policy of naming its products with generic names, such as Model 1440 Calculator, MIT left the naming of the computer to the magazine editors, who chose the Altair for a star that was featured on an episode of Star Trek.
Due largely to the magazine feature, sales were larger than anticipated. Although MITS needed to sell only two hundred units in order to break even, they had received more than a thousand orders for the Altair 8800 by February, and more than five thousand by August. Although MITS quoted a 60-day delivery time, they were unable to meet the demand for a few months.
For the first half of 1975, MITS had no competition, but it wasn't long before a company known as IMS Associates began producing a clone of the Altair 8800, marketed as the IMSAI 8080, which was in production until 1978, longer than the Altair.
The Altair 8800 could be purchased as a kit or as an assembled computer. The assembled computer shipped in a two-piece case. The backplane and power supply were mounted on a base plate, along with the front and rear of the box, while the lid formed the top, left, and right sides of the box. The front panel included several toggle switches to feed binary data directly to the machine's memory, as well as several red LEDs to read these values back.
The Altair did not come with a keyboard. Rather, programming the computer was a tedious process, as it required toggling switches to positions that corresponded to the desired microprocessor instruction in binary. Hobbyists would outfit the machine with additional parts and components, such as a keyboard, monitor, disk drive, and plugin boards to expand its capabilities.
Functioning as Traf-O-Data, Bill Gates and Paul Allen wrote a programming language for the Altair 8800, known alternately as Altair BASIC or MITS 4K BASIC. Soon after, Gates and Allen formed Microsoft. Altair DOS began shipping in August of 1977.
MITS made some improvements on the Altair 8800, fixing a few other problems that had been identified in the original device, releasing it as the Altair 6800b.
MITS also made the Altair 680b with a Motorola 6800 CPU. The 6800b didn't sell well, however. It was too small to look real, and memory cost more than the computer.
In 1977, MITS was acquired by Pertec Computer Corporation. The first product built by Pertec after their acquisition was the Pertec/MITS 300, which included the 300/25 and the 300/55, both of which included the hardware and software in one integrated package, intended as business systems. Prone to overheating, this system had a short life span.
Pertec then rebranded the computer line, producing the Pertec PCC-2000, which was available with MITS DOS or CP/M. Too expensive for the market, it didn't sell well. The PCC-2100, with two disk drives and a tape drive, also didn't make a large impression.
The Pertec XL-40 was more successful. The 16-bit system came in two versions, one with four tape units, two floppy disk units, and four rigid disk units, while the other featured two large-capacity (70 MB) disk units, a line printer, four station printers, a card reader, four communication channels, and thirty proprietary coax terminals. This system was intended to replace the old IBM card punch machines.
Last was the Pertec 3200, a complete departure from the Altair. Its primary operating system was a multi-tasking, multi-user OS that could also run Unix. There were four models: 3200, 3200, 3230, and 3240, intended for large corporations.
The focus of this category is on the Altair 8800 and other systems produced by MITS, although the Pertec systems are appropriate here, as well.
Recommended Resources
Currently available at the same price as the original Altair 8800, the full-size, fully-functional replica duplicates the look, feel features, performance, and limitations of the Altair 8800. Software developed for the Altair 8800 will run in the same manner, and at the same speed, on this clone. Details of the computer are given, with ideas as to contemporary purposes for such a machine, and a video library of demonstrations and tutorials are put forth on the site. A user forum is included.
https://altairclone.com/
Altair BASIC 3.2 (4K) - Annotated Disassembly
This is a complete annotated disassembly of the Altair BASIC 3.2. The author has followed the program order, naturally dividing the code into three sections: the interpreter, the maths package, and the initialization, each preceded by explanations and overviews, and including subsections, along with the base, size, and key functions of each. In addition, the total size of each section is noted. For example, the manner in which BASIC arranges memory is given, along with code.
http://www.altairbasic.org/
The Mini-Altair is a retro computer that functions like the Altair 8800 and can run original, unmodified software designed for the original Altair 8800. The simplest Altair configuration that could run 4k BASIC was the 8080A CPU board, at least 4k RAM, and a serial IO interface. In producing the system, the project resulted in a series of versions, each of which are highlighted here, with details relating to the development of each, including schematics and other information.
http://mini-altair.tripod.com/
Developed in the mid-1970s, the MITS Altair was the first commercially available microcomputer. This is a digital museum featuring the history of the Altair 8800 and other systems manufactured by MITS, as well as its boards, peripherals, and other parts and components, as well as the text of a MITS seminar on computer concepts, and a history of the microcomputer revolution by Frank Delaney, available in sixteen segments or all on one page.
http://www.virtualaltair.com/
