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Lee Felsenstein is an electrical engineer who played a key role among the hardware hackers who invented the personal computer. Felsenstein's approach to hardware development was significantly influenced by [[Ivan Illich]]'s vision of [[Convivial Tools]] that would be maintained and developed by a community of users.

==A Berkeley Radical==
Lee Felsenstein was studying electrical engineering at Berkeley in 1964 when the Free Speech Movement occurred, and was one of 768 arrestees in the "Sproul Hall Sit-In" of December 2-3, 1964. During the sixties he also contributed time as a technician and journalist on the weekly underground newspaper called the Berkeley Barb, and also on another underground newspaper called the Berkeley Tribe, which was formed by dissatisfied Barb staff. Felsenstein dropped out of University of California Berkeley at the end of 1967 and worked as an Electrical Engineer at the Ampex Corporation from 1968 through 1971, but then re-enrolled and obtained a B.S. in EECS in 1972.

==Resource One==
In 1971 [[Lee Felsenstein]] came into contact with a group of four computer science students who had dropped out of Berkeley and were living in a warehouse community in San Francisco. They obtained the donation of an obsolete time-sharing computer, an XDS 940, and set up the non-profit organisation Resource One to try to deliver computing power to non-profit organisations and social-action groups.

Lee Felsenstein signed on as chief engineer. The computer was delivered in 1972 in two trucks, and it also required 23 tons of air conditioning. The hardware was old and Felsenstein had numerous problems trying to keep it running. A friend of Felsenstein’s, a systems programmer named Efrem Lipkin, directed the project of writing an information retrieval system, which took more than a year to write and debug.

When the system was running they proposed it for use by Bay Area switchboards (volunteer information and referral agencies), for a minimal charge of $150 a month for rental of a teletype and a modem, but even that was too expensive for the non-profit switchboards. Efrem Lipkin had the idea of setting up a public terminal somewhere to serve as an electronic bulletin board, just so they would have some data in their system. The first public terminal was set up in 1973 in Leopold’s Records, a record store that was run by the UC Berkeley Student Union.

==The Pennywhistle modem==
The Resource One terminal used a modem which cost $300 (the equivalent of several time that today). Felsenstein set out to build a cheaper modem himself, running off of a cassette tape recorder, which was the inexpensive storage standard of the day, but which would not work with the regular existing modems. He successfully developed such a modem for use with the Berkeley terminal. After further development it appeared in 1976 as a commercial hobby kit called the Pennywhistle modem.

==The Convivial Computer==
In January of 1974 they moved the terminal to the [[Whole Earth]] Access store on Shattuck Avenue. They leased a fancy Hazeltine 1500 CRT terminal, for which they had a service contract. One day when the service technician was working on it, he dropped the circuit board for the keyboard, breaking the ceramic pack on one of the chips, but then simply put the board back in place, explaining: "it works." 

That experience started Felsenstein thinking about how to make such a system survive in a public access environment. Efrem Lipkin was in favor of armoring the equipment to keep everybody out, but Felsenstein took the opposite tack, under the influence of Ivan Illich’s book "Tools for Conviviality." Felsenstein was notably impressed by Illich's description of how radios were repaired in the jungles of Central America. The radio technology was sufficiently accessible to peasant users and brought out their inherent tendencies to learn. If you tried to fool with a radio, the tube might overheat, but it would survive and give you some warning that you had done something wrong. This is quite different from the standard industrial model, in which something tinkered with will simply break. The radio however survived in the jungle environment because it "grew up" a cohort of people around it who knew how to maintain and sustain it.

To transpose such a model to computer, however, was particularly challenging. As an electrical engineer Felsenstein had extensive experience with disruptive factors like noise in circuits, and the reliability required in computers, which have to work at every clock cycle, appalled him. He nonetheless convened a discussion group around the concept of a convivial computer, and about five people showed up, including Bob Marsh and Ray Bruman. Felsenstein’s proposition, following Illich, was that a computer could only survive if it grew a computer club around itself.

==The Tom Swift Terminal==
Felsenstein's discussion group also discussed the TV Typewriter, about which Don Lancaster had recently written an article in Radio Electronics. Radio Electronics received ten thousand orders for the two-dollar plans in Lancaster’s article, showing how to construct a little box, for about a hundred dollars worth of parts, which you could connect a TV set to make a rudimentary terminal. In comparison, the Hazeltine terminal cost about $1600.

Lancaster’s model was in fact very difficult to construct, since it used sequential, shift register memory, and was tricky to build and debug, because it used lots of little analog delay pulses. Also, the TV Typewriter functioned rather poorly as a terminal, because it displayed one page at a time, and when you got to the end of one page and the last character went up on the screen, the screen blanked and you saw only the next typed character. It had no buffering for back scroll. Felsenstein contacted Don Lancaster about these deficiencies, and Lancaster said, "It isn’t supposed to be a computer terminal, people just want to put up characters on their TV sets." Felsenstein concluded that the people who tried to make the TV Typewriter simply felt an urge to gain control over technologies that they knew would affect their lives.

Lancaster also told Felsenstein that he was working on a new version that used random access memory chips, which were just then becoming available. Felsenstein realised that once you had installed random access memory in a simple computer, you could use that same memory to run the terminal. He therefore defined a terminal that used a three card set: a memory card, a card to put data into the memory, and a card to get information out of the memory and put it to the screen. To connect the three cards he defined a 44-pin bus structure that used cheap Vector connectors. That was in fact the genesis of the architecture of the personal computer. 

Felsenstein defined what the terminal would do when it got various control characters, and in the fall of 1974 he put together a specification that he called "The Tom Swift Terminal, or a Convivial Cybernetic Device." He mimeographed the specification and sold it for the price of making the copy.

The common memory and the bus structure made this device potentially much more than a terminal. You could plug in additional boards, additional memory and possibly even a microprocessor.

Just as the boards plugged into the bus, Felsenstein wanted to make sure you could plug the busses together to expand them. The builder, the user, could thus control the rate at which the device grew upwards into an intelligent terminal and then into a computer. This vision of the convivial computer, which Felsenstein transmitted to the other members of the [[Homebrew Computer Club]], in fact determined the whole subsequent development of the personal computer. When IBM entered the field a few years later, they were obliged to use a similar open, modular architecture, in order for their machine to gain acceptance. This is also the reason it was so easy for other manufacturers to make IBM clones.

==The Homebrew Computer Club==
In January 1975 appeared the issue of Popular Electronics magazine advertising a kit for hobbyists to build the MITS Altair 8800, now considered to be first microcomputer. The Altair catalyzed the formation of the [[Homebrew Computer Club]], an informal group of computer enthusiasts who met to discuss the construction of personal computing devices, and from whose ranks came many of the designers of early microcomputers and founders of microcomputer companies. 

Ever since Resource One days, on Wednesday nights Felsenstein had been going down to potluck dinners at the People’s Computer Center in Menlo Park, run by Bob Albrecht, who also ran the [[People’s Computer Company]] newsletter. When the Altair was announced, a call for a meeting went out all those who were on the PCC visitor list. Felsenstein took to the meeting a version of the Altair that had been sent to People’s Computer Company as a review copy. They had given it to Felsenstein, who had assembled it and taken it to show Efrem Lipkin, who considered it useless, since there was nothing to it but switches and lights. Lipkin kept it as a sculpture in his living room, on the same table with his guinea-pig cage, with its lights flashing to keep the guinea pigs company. Felsenstein retrieved it and returned it to PCC, and it turned up as the centerpiece of the first [[Homebrew Computer Club]] meeting.

At the first meeting thirty people stood around the Altair and discussed what they knew about it and told about their own ongoing projects. They began to understand that as a group they probably knew as much as the MITS people. During the following weeks the members dissected the Altair, and began planning their own projects, which included building memory boards for the Altair, peripherals, a better bus, and even competing computers. After the Homebrew Computer Club had been operating for sometime [[Lee Felsenstein]] became the facilitor for the Club, an informal master of ceremonies directing the meetings and discussions. As many as 750 attended the meetings and they became a major locus of information exchange on computers in the Bay Area.

==Processor Technology Corporation==
In late 1974, Bob Marsh, who was unemployed and casting about for something to build, convinced Felsenstein to rent a garage with him. Felsenstein set up his bench downstairs and Marsh took the little loft office. When the Altair came out in January 1975, Marsh showed it to Felsenstein and said "Look at this picture on the front. It’s clear it’s a phony.... This thing has nothing in it, it’s an empty box." The Altair was little more than the microprocessor interfaced to a series of connectors. Marsh wanted to start building peripherals for it, so he and his friend Gary Ingram formed Processor Technology Corporation. Felsenstein remained a consultant and never became an employee or part of the corporation, but took on contract work drawing schematics and writing assembly manuals.

When Felsenstein opened up the Altair box and looked inside he was unimpressed. Of four possible places for motherboards, only one was filled with a group of four sockets, and only two of the sockets were occupied, one by the microprocessor card, and one by the memory card. The memory card had sockets for eight RAM chips, but MITS only supplied two chips for a total of 256 bytes of RAM, which was not enough to support the kind of programming that most people wanted to do. The processor card was nothing more than the 8080 processor driving the lines on the bus through buffers. They had installed separate data-in and data-out buses, which was inefficient, because you never did data transfers both ways at the same time. That indicated to Felsenstein that the designers of the Altair did not really understand what a computer bus was.

Also, the Altair needed everything, including I/O (input/output) and memory that worked. Bob Marsh quickly saw that he could build a memory board from the same chips which Felsenstein was using on the Tom Swift Terminal. Marsh made a satisfactory delay generator circuit, Felsenstein wrote the manuals, and Marsh’s Processor Technology Company was off and running.

Felsenstein’s shared-memory alphanumeric video display design, the Processor Technology VDM-1 video display module board, was widely copied and became the basis for the standard display architecture of personal computers.

Lee Felsenstein working for Bob Marsh’s Processor Technology also designed a fully contained computer for an issue of Popular Electronics. This Intel 8080 based computer was named the "Sol," after Popular Electronics editor Les Solomon. The Sol sold for under a thousand dollars and included many more capabilities than the Altair.

==The Osborne computer==
Lee Felsenstein also designed the Osborne 1 Computer, the first mass-produced computer that was "portable," in the sense that it could be conveniently carried from one place to another and there plugged in and used. Felsenstein was commissioned to develop this first portable computer by Adam Osborne, who founded the Osborne Computer Corporation in 1980.

The Osborne 1 was released in April, 1981. It weighed 23.5 pounds (10.7 kg) and cost US$1795. The size was limited to the dimensions that could fit under a jetliner seat.

==Recent years==
In 1998 Lee Felsenstein founded the Free Speech Movement Archives as an online repository of historical information relating to that event.

In 2003, working with the Jhai Foundation of San Francisco, Felsenstein designed an open-source telecommunications and computer system for installation in remote villages in the developing world. This system was dubbed "the Pedal-Powered Internet" by the New York Times Magazine due to its reliance on pedal power generation. The design has been tested on an Indian reservation in the US and continues in development in India. 

==Links==
*[[Wikipedia]] article on Lee Felsenstein: http://en.wikipedia.org/wiki/Lee_Felsenstein
*[http://conviviality.ouvaton.org Convivial Tools Encyclopedia] article on Lee Felsenstein: http://conviviality.ouvaton.org/article.php3?id_article=39
*Felsenstein interview in the newsletter of the Computer History Association of California (1995): http://opencollector.org/history/homebrew/engv3n1.html

[[Category:Convivial Tools]]
[[Category:Hacker Generation]]