LINC

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The LINC, short for Laboratory Instrument Computer, was an early 12‑bit computer designed in 1962 at MIT’s Lincoln Laboratory. It’s often called the first minicomputer and a forerunner to the personal computer because it was small enough to sit in a lab and could be connected directly to scientific instruments.

Who made it and what was it like
- Designers: Wesley A. Clark and Charles Molnar.
- Origins: Created at MIT for NIH researchers; the project later moved and the machine was renamed LINC.
- Builders: Digital Equipment Corporation (DEC) and Spear Inc. of Waltham, Massachusetts.
- Price and production: About $43,600 per unit in the early 1960s; around 50 units were shipped, with 21 sold by DEC.

What it looked like and how it worked
- Hardware: A 12‑bit, 2048‑word memory machine built from transistors.
- Memory layout: The machine had two memory sections—the first 1024 words could run programs, the second 1024 words were data. This is like a simple Harvard‑style memory.
- Speed and arithmetic: Each instruction took about 8 microseconds to run. It used ones’ complement arithmetic (which means plus zero and minus zero are treated as different values).
- I/O and lab focus: The LINC was designed to connect directly to laboratory equipment. It included analog inputs and outputs and could control instruments through special I/O interfaces.
- Display and input: Programs could display text on a small CRT screen (a Tektronix oscilloscope adapted for the job) and input data with a keyboard. Some setups used a teletype printer for output.
- Front panel: A control panel with knobs and switches allowed users to single‑step programs, pause at certain points, or stop at specific addresses for debugging.

LINC tape and storage
- LINCtape: A core feature of the system was the LINCtape, a compact magnetic tape that was fast and reliable for the time. It stored about 400 kilobytes and had a simple, block‑based format that allowed easy updating of data and programs.
- Why LINCtape mattered: The LINC’s operating system was built around this tape system, making it a central part of using the machine.

Hardware and evolution
- Keyboard and display quirks: The original LINC used a unique keyboard with locking keys. Later versions moved to more familiar Teletype terminals.
- Extensions and variants: There were several follow‑ons, including μ‑LINC and μ‑LINC 300. DEC later released LINC‑8 (which mixed a PDP‑8 CPU with a LINC) and the PDP‑12. The PDP‑12 could run both PDP‑8 and LINC programs, though it had its own quirks.
- The LINC influenced later machines: DEC drew on the LINC’s ideas for future lab computers, and the concept of a portable, instrument‑connected computer helped shape the design of early microcomputers and modular instruments.

Why the LINC matters
- It’s considered one of the first minicomputers, bringing computer power into the laboratory to work directly with scientific experiments.
- Its LINCtape storage and its emphasis on instrument control were innovative for the time and influenced later computing and lab equipment, including ways to integrate computation with measurement.

In short, the LINC was a compact, instrument‑friendly computer from the early 1960s that helped bridge the gap between large mainframes and personal computers, by bringing computational power directly to the lab bench.