LINC

The LINC (Laboratory INstrument Computer) was a special kind of computer known as a minicomputer. It was created in the early 1960s and is considered one of the first of its type, helping to pave the way for the personal computers we use today. Originally named the Linc, it was developed at MIT's Lincoln Laboratory and later renamed LINC.

Designed by Wesley A. Clark and Charles Molnar, the LINC was a small, transistorized computer with 2048 words of memory. It was especially good at connecting with laboratory equipment, making it very useful for scientific research. The design was placed in the public domain, which meant anyone could use and build upon it.

About fifty LINC computers were made, mostly by Digital Equipment Corporation. They cost around $43,600 at the time, which would be about $464,000 today. The LINC included features like oscilloscope displays and special input devices, and it helped researchers manage and analyze their experiments in new ways.

Architecture

The LINC had 2048 memory spots, but only the first 1024 could run programs. The other half was for storing data. It had special areas for handling tasks like calling other programs and keeping track of positions.

The LINC could use a special area to help with calculations and had ways to connect to devices like a keyboard and a screen. It could also send and receive printed text with a special machine.

Control panel

The LINC control panel helps users go through programs step by step and find mistakes. Users can pause the program when it reaches a certain point or when it uses a specific memory address. There are buttons to move one step at a time or to continue running the program. The speed can be changed using a knob and a switch, allowing users to see how fast the computer works, from very slow to full speed.

LINCtape

The LINC computer had a special part called LINCtape. This tape was very important because the computer's operating system needed it to work. It was like a small, quick disk but slower to find information. Unlike bigger machines that used large tapes taking minutes to move, LINCtape was small and fast, storing about 400,000 pieces of information. It could rewrite data in the same spots over and over.

Files on LINCtape had names with six letters, and each name could hold two types of files. Because the LINC had very little memory, it often needed to move data to and from the LINCtape. Later, a similar idea was used by Digital, called DECtape. LINCtape was known for being very reliable, even if someone poked holes in it. The tape could still be read because it saved data in two places. It worked well even when the tape moved at different speeds.

Keyboard

The LINC computer had a special keyboard made by Soroban Engineering. Each key could lock into place when pressed, keeping other keys locked until the computer read the pressed key. This design could make typing slower and caused issues with pressing two keys at once.

Later versions of the LINC computer used different keyboards, like the Teletype Model 33, Teletype Model 35, and Teletype Model 37, which were easier to use.

Knobs

The LINC had eight knobs that you could turn. Each knob could be read by the computer with a single command. The dial box was a useful way for people to give input to the computer before mice were common. For example, one knob might change how big a graph looks, and another could show the exact value of a point on the graph.

Text display

The LINC computer could quickly show text on a screen using a special design. Its screen was a small 5-inch square CRT, similar to a device called an oscilloscope, which could also help fix the computer if needed.

The screen used a special kind of material that kept images visible for a while, even when drawn slowly. Programmers had to be careful because showing the same spot too often could damage the screen quickly.

Teletype output

When the LINC computer needed to print information, it used a special machine called a Teletype Model 33. To make this work, the computer would change its own codes into another set called ASCII. It then used timing loops to turn a tiny part of its system on and off. This created the right signals to make the Teletype printer work at a speed of 110 characters per second.

Laboratory interface

The LINC computer had special parts that let scientists connect their own experiments to it. It included tools to change signals from sensors into numbers a computer can use, and it could also change numbers back into signals. There were also six switches that could be used for control.

Variants

Besides the original LINC, there were a few different versions made later. These included the micro-LINC from 1965, the micro-LINC 300 from 1968, and the LINC-8. Each of these versions had small changes in how they were programmed, what tools they used for input and output, and how fast they could work. Some also used newer technology called integrated circuits.

LINC-8 and PDP-12 computers

The LINC helped inspire some early computers made by Digital Equipment Corporation. They first created the very popular PDP-8 before making the LINC-8. The LINC-8 could run like either a PDP-8 or a LINC, but only one at a time. Later, they made the PDP-12, which could switch between acting like a PDP-8 or a LINC. The PDP-12 was the last of their machines to use LINC-style instructions.

MINC-11 computer

Digital made a version of the PDP-11/03 called the MINC-11. It was built into a portable cart and could be used with special laboratory tools for measuring and controlling things. It had a programming language called MINC BASIC that worked well with these tools. MINC stands for "Modular Instrument Computer." The name was chosen to remind people of the LINC, but this 16-bit machine was very different from the LINC and did not work the same way.