When I first became interested in computers I was in high school. Most computers were expensive. Digital Equipment Corporation had just started supplying college laboratories with digital logic that was affordable for building dedicated digital lab equipment. My uncle Kell worked in such a lab building hardware to support experiments. I remember browsing through the DEC catalogs and handbooks when I would visit him.
Then, soon after I graduated from high school, Popular Electronics published a two part article on how to build a microcomputer called the Altair 8800. A small company in Arizona was selling a kit of parts along with a printed circuit board and a cabinet. The Altair had toggle switches for entering ones and zeros and lamps for displaying binary values. I had no idea of how to program but I wanted one.
Soon, there were many single board microcomputers, many fully assembled. There was the Kim I and the COSMAC Elf. These computers sported calculator style keypads and seven segment numeric displays. They also had interface chips that allowed them to be hooked up to teletypes or the new terminals that were initially called glass teletypes. And I wanted one of each.
Then there was a period characterized by computers with built in keyboards that produced video signals that could be fed to a regular television using an adapter that converted the video signal into a TV signal. The Apple II and the Ohio Scientific C1P were examples of these. I owned a C1P for a short while.
A little bit later, Commodore came out with the Commodore Pet computer that had a built in display and a built in cassette tape recorder to store programs on. I worked on a Pet writing Computer Assisted Instruction while I was in the Army.
Another computer or this era was the Radio Shack TRS-80. I wrote a program for my father on one that he borrowed from the school where he taught. The program computed a salary schedule based on a matrix that ran years of experience along the X axis and level of education along the Y axis. There were three of these matrices, one contained the number of individuals in each category, one contained the salary for each category, and the third contained the amount that each category would cost. I then summed all the cells of the last matrix to compute how much that salary schedule would cost. He was able to successfully negotiate a substantial raise for the teachers in his district using the program. This was before VisiCalc was invented.
I’ll write more about the evolution of small computers in a future post.