Sol-20
It nevertheless became clear that owning my own computer was becoming economically feasible.
I remember going to a West Coast Computer Faire in the San Francisco Civic Auditorium. The place was packed with booths from vendors selling their electronic wares, and was also packed with nerdy computer enthusiasts (most of us novices, at least in terms of personal computers). I went there with the specific purpose of identifying a computer to buy. Based on what I saw, I narrowed my choice to either an Apple II or a Processor-Technology SOL-20. The Apple had color graphics, and was slightly more expensive. The Sol had what was becoming an industry standard bus, the S-100 bus, which first appeared in the Altair computer. I ended up choosing the Sol, both because of its price, and the standard bus.
The Sol came with a small amount of memory (8K, I think). I plugged in a black-and-white monitor to the optional VDM-1 video adaptor. Programs were loaded from audio tape cassette.
The Sol had a built-in ROM monitor called SOLOS. Here’s a screen shot:
Here’s a game that ran on the Sol:
And here’s another (Star Trek):
It also came with a BASIC interpreter:
It also came with an assembly-language system called ALS-8. Unlike the other software mentioned here, ALS-8 did not come on audio cassette. Instead it came in ROM on an expansion card.
When I first got the Sol, I assumed I would be doing most of my programming in assembler, since I was somewhat of an assembler snob in those days—BASIC was for wimps. But I quickly learned how primitive the 8080 machine language was compared to the mainframe systems I was used to. On the System/360, for example, one could move a string from one place to another with a simple MVC instruction. On the 8080, this required writing a loop. Worse, the 8080 is an eight-bit machine, as previously mentioned, which meant if you wanted to do arithmetic on real-world numbers you had to use some software subroutines—which you would probably have to write yourself.
So I did end up writing BASIC programs for practical things I wanted to do, like balance my checkbook or keep track of my gasoline mileage. I did also write assembler code, but it tended to be more experimental and less practical.
Eventually I wrote a cross-assembler for 8080 code that ran on the System/370. I used this to get assembler listings, which I couldn’t get at home since I didn’t have a printer yet
I soon grew tired of loading files from audio tape which was slow and error-prone. So I bought a NorthStar disk drive. This came with its own small operating system:
NorthStar DOS, as it was known, came with its own version of BASIC, which included the capability of reading and writing disk files.
Eventually I added a second disk drive and more memory until I maxed the memory at 56K.
It was on the Sol that I ran my first word-processing program, Electric Pencil. My brother in law wrote his doctoral thesis on that system. I used a modified IBM Selectric Typewriter as a printer.
During the time that I owned the SOL computer I began working for ITEL. I bought an acoustic coupler, the only type of modem the telephone company would allow at that time and wrote the software necessary to connect between my SOL computer at home and the computers at work. I wrote an article about that program which was published (source code and all) in Dr. Dobb’s Journal:
My job at ITEL caused me to move from Oakland to Palo Alto. Once here I discovered a number of users groups, designed to support those people brave enough to try the new home-computer technology. I ended up attending sessions of the North Star User’s group, which held meetings at a computer shop on El Camino.
I also had the opportunity to attend the Homebrew Computer Club, which met on the Stanford campus. But “homebrew” sounded too much like hardware for me—I’m a software guy. I have few regrets in my life, but not ever going to the Homebrew meetings is one of them. It was there that Jobs and Wozniak introduced the Apple computer (although I was probably still living in Oakland when that occurred). Homebrew is still mentioned whenever the history of personal computers is discussed. I could have been part of that.