COMPUTER MEMORIES, Chapter 23

SWAC COMPUTER, at UCLA
While at RAND I remember going to UCLA (perhaps 6 or 8 times) where they had a hand-built computer called SWAC (Standards Western Automatic Computer). For one project at RAND, they needed a copy of a file of 9,000 cards computed and punched by the SWAC, that contained sines, cosines, tangents, etc. (from 00.00° to 89.99°, or something like that). It was time consuming and/or beyond the IBM 701 computer’s (or programmer’s) ability to compute all that stuff as needed, so one time I had to make a copy of the card file created by SWAC. We read the file onto a magnetic tape, and the 701 computer looked and looked for each number as needed. Within a short time, computers could do all this as needed, and the card files were no longer needed.

The SWAC, built before IBM or UNIVAC were in the computer business, used a speaker system to keep the operator aware of what it was doing. They could tell by the sound it made, if it was “hung-up” in an endless loop, or whatever. Different functions, resulted in different tones. Using that sound system, programmers were forever programming something that would result in music, with the computer playing songs you could recognize. That was true on many of the early computers, including the Johnniac at RAND. Years later Control Data Corp. delivered a computer to some installation in England with “God Save the Queen” already loaded, and that was the first thing heard, when the computer was turned on.

The SWAC Computer worked with the hexadecimal number system, a system based on the number 16, rather than the base number 10, as all of us are familiar with. They used 0 to 9, and u,v,w,x,y,z as the 16 symbols for all the combinations of four binary bits. You don’t really want to know what that means! Trivia: My brother, a college professor (who taught all kinds of college level math courses, in addition to 40 other subjects!) one time needed to create a hexadecimal system for a class project. He was totally unaware of any computer system (and maybe the computer did not exist yet), but he had used u,v,w,x,y,z as the added 6 symbols needed to make up the base-16 number system.