Interesting reading in the latest in the Bicycles For The Mind series, about the social and technical history of the hobby computer, arising from the electronics hobbyist scene, initially from people who wanted to learn about computers, without any application in mind:
From ACS to Altair: The Rise of the Hobby Computer
Blankenbaker was the first of the amateur computerists to try to bring his passion to market; the first hobby-entrepreneur of the personal computer. He was not the most successful. I found no records of the sales of the NRI 832, but by Blankenbaker’s own testimony, only forty-four Kenbak-Is were sold. Here were home computer kits readily available at a reasonable price, four years before Altair. Why did they fall flat?
That’s the previously-mentioned National Radio Institute NRI 832 (1970)
The Emergence of the Hobby-Entrepreneur
As integrated circuit technology got better and cheaper, the situation for would-be computer builders gradually improved. By 1971, the first, very feeble, home computer kits appeared on the market, the first signs of Gray’s “SACK.” Though neither used a microprocessor, they took advantage of the falling prices of integrated circuits: the CPU of each consisted of dozens of small chips wired together. The first was the National Radio Institute (NRI) 832, the hardware accompaniment to a computer technician course disseminated by the NRI, and priced at about $500. Unsurprisingly, the designer, Lou Freznel, was a radio hobby enthusiast, and a subscriber to Stephen Gray’s ACS Newsletter. But the NRI 832 is barely recognizable as a functional computer: it had a measly sixteen 8-bit words of read-only memory, configured by mechanical switches (with an additional sixteen bytes of random-access memory available for purchase).
There’s a footnote to that paragraph with good links:
- Lou Freznel, “The History of Personal Computers – Part 1: The East Coast Version,” Electronic Design (December 12, 2013)
- William G. Wong, “Remembering a Communications Legend | Electronic Design,” Electronic Design (January 19, 2023)
Later in the article, we reach 1974:
The SCELBI-8H and Mark-8 looked much more like a “real” minicomputer than the NRI 832 or Kenbak-I. A hobbyist hungry for a PDP-8-like machine of their own could recognize in this generation of machines something edible, at least. Both used an eight-bit parallel processor, not an antiquated bit-serial architecture, came with one kilobyte of random-access memory, and were designed to support textual input/output devices. Most importantly both could be extended with additional memory or I/O cards. These were computers you could tinker with, that could become an ongoing hobby project in and of themselves.
And then, the 8080 comes into play:
For Roberts, the growing hobby interest in home computers offered a chance to save a dying MITS, and he was willing to bet the company on that chance. Though already $300,000 in debt, he secured a loan of $65,000 from a trusting local banker in Albuquerque, in September 1974. With that money, he negotiated a steep volume discount from Intel by offering to buy a large quantity of “ding-and-dent” 8080 processors with cosmetic damage. Though the 8080 listed for $360, MITS got them for $75 each. So, while Wadsworth at SCELBI (and builders assembling their own Mark-8s) were paying $120 for 8008 processors, MITS was paying nearly half that for a far better processor.
