The work on advanced Laboratory INstrument Computer (LINC) was started in May 1961 by Wesley Clark and a team of engineers, led by Charles Molnar (Clark designed the logic, while Molnar did the engineering) at Lincoln Laboratory of MIT, Massachusetts, and the machine was eventually launched by Digital Equipment Corporation (DEC) in March 1962 (see the nearby photo). With its digital logic and stored programs, the LINC is accepted to be the first interactive personal computer in the world.
In 1961 Wesley Allison Clark (1927-2016), an electrical engineer at Lincoln Laboratory of MIT, who had contributed substantially to the development of the large TX-0 and TX-2 computers, ordered by the US Navy, realized that time sharing, used in these highly advanced machines, is not the only solution to the problem of direct access. He proposed building a relatively inexpensive, general-purpose computer that could be controlled easily by biomedical researchers.
Initially ignored by Lincoln Lab’s management, Clark continued to work on his idea for a small computer. He disappeared from the Lab for about three weeks at the end of 1961, and returned with a complete design for a small computer, with characteristics that marketing representatives would later call user-friendly.
Clark’s computer was designed to satisfy four basic criteria:
1. Easy to program
2. Easy to communicate with while in operation
3. Easy to maintain
4. To be able to process biotechnical signals directly.
No computer in the early 1960s could come close to fulfilling those objectives. Later, Clark added two shrewd criteria:
5. It could not be too high to see over, and
6. It must cost at most $25,000 (this was the amount a lab director could spend without higher-level approval).
LINC originally had one kilobit of core memory (1024 words), which was expanded to 2 Kb later. It was designed for interactive use via Graphical User Interface, with a 256 x 256 CRT display and four knobs (the equivalent of a mouse in those days) to enter variable parameters. The Soroban keyboard, for alpha-numeric entry, has keys that lockdown when pressed, and pop back up when the computer has read them, thereby solving the problem of type-ahead! Removable media was two LINC tape drives — the predecessor of DEC tape, each spool holds 512 blocks of 256 12-bit words, or 512 bytes—the characters (upper-case, plus various greek and math symbols) fit into 6 bits.
The standard program development software (an assembler and screen editor) of LINC—so-called Assembly Program (LAP), designed by Mary Allen Wilkes, was integrated with the Assembler and File System and was written for users, not computer professionals. LAP made it fairly easy to program LINC for biomedical experiments and, in its last version, was sufficiently flexible to allow for word processing.
A typical configuration of the machine (see the nearby image for one of the prototypes in MIT) included an enclosed 6’X20″ rack, four boxes holding tape drives, a small display, a control panel, and a keyboard. Analog inputs and outputs were part of the basic design. In these, the tall cabinet sitting behind a white-Formica-covered table held two somewhat smaller metal boxes holding the same instrumentation, a Tektronix display oscilloscope over the “front panel” on the user’s left, a bay for interfaces over two LINC-Tape drives on the user’s right, and a chunky keyboard between them.
Linc was manufactured commercially by DEC (starting in 1964) and Spear Inc. of Waltham, MA. The first LINC included two oscilloscope displays. Over the ensuing years, nearly a hundred LINCs were built for use in medical research before the design was absorbed into the DEC PDP-12. Twenty-one were sold by DEC at $43600 (a bargain at the time).
When a scientist sat down at the LINC keyboard, he had at his disposal a complete and comprehensible computer system. He could create a program and execute it in one sitting. Perhaps most elegantly, as the data were displayed an experiment could be tuned instantly by turning a knob hooked to an analog-to-digital converter. What sixth graders now take for granted was a remarkable achievement that led to a “computer pioneer” award to Wesley Clark—by the IEEE (Institute of Electrical and Electronic Engineers), which acknowledged Clark as the designer of the first personal computer, Eckert-Mauchly Award and membership to the National Academy of Engineering.
Wesley Clark had a small but key role in the planning for the ARPANET (the predecessor to the Internet). He suggested to Larry Roberts the idea of using separate small computers (later named Interface Message Processors) as a way of standardizing the network interface and reducing the load on the local computers.
Biography of Wesley Clark
Wesley Allison Clark Jr. was born in New Haven, Connecticut, on 10 April 1927, to Wesley Allison Clark Sr. (1897–1959) and Eleanor Southard Ella Kittell (1898–1982). He had a sister: Joan Murphy. Wesley Jr. grew up in Kinderhook, New York, and in northern California, where the family moved at the end of the 1920s. He attended the University of California, Berkeley, where he graduated with a degree in physics in 1947.
Clark became interested in computers while attending graduate school. In 1951, he began working in the computer lab at MIT where he learned programming and was involved in the Whirlwind project. Clark worked for MIT in various capacities three different times. “I’m probably the only person in the world fired three times by MIT for insubordination,” Clark used to say.
After leaving MIT for the final time, Clark worked at Washington University from 1964 to 1972. He has been a consultant since 1972 and was a co-founder of Clark, Rockoff, and Associates in Brooklyn, N.Y., with his wife, Maxine Lieberman Rockoff (born 1938). The family had four children—a daughter, Alison Eleanor, and three sons: Brian, Douglas Wells, and Peter. Clark’s oldest son, Douglas Wells, was a professor of computer science at Princeton University.
In 1981, Wesley Clark received the Eckert–Mauchly Award for his work on computer architecture. He was awarded an honorary degree by Washington University in 1984 and was elected to the National Academy of Engineering in 1999. Clark is a charter recipient of the IEEE Computer Society Computer Pioneer Award for “First Personal Computer”.
Wesley Clark died on 22 February 2016, at his home in Brooklyn due to severe atherosclerotic cardiovascular disease.