I came to technical writing through Kelly Temporary Services in 1980. I was hired as a temporary proofreader at FMC Corporation in San Jose, California. FMC started in 1883 when John Bean invented an innovative insecticide spray pump. In San Jose in the early 1980's we built tracked military vehicles including the LTV-7 landing craft, the M113 armored personnel carrier, and the Bradley Fighting Vehicle, all of which I worked on.
I worked a few months as a proofreader before being taken on as a direct hire as a technical editor. I worked in that position for several more months before moving up to technical writer.
At that time the state of the art equipment for the technical writer was the IBM Selectric typewriter. Typesetting was done by a special department (which I worked in briefly) that manually typed the information into a mainframe word processing program. This turned out to be useful years later when I was learning HTML. In that old program you had to enter carriage returns, tabs, etc. as tags just as in HTML. Later I worked with a state-of-the-art Kodak typesetting system that printed publication-quality pages on photographic paper at an unimaginable cost-per-page.
During that period there were no classes in technical writing, much less college degrees. Companies were looking for journalism majors, which I wasn't. I got in by going through the temping back door, which is still a nice inroad if you don't have the "right" degree.
When I was working at FMC the entire technical writing department, below middle management, was under 30 years old. Anyone older either moved into management or on to another job. In Silicone Valley at that time, if you stayed more than two years at a job you were stagnant. I didn't buy into that environment and moved on to Denver and Martin Marietta in December 1983.
When I left, an Apple II personal computer cost $10,000 and PC's were in the future.