Hi All,
I get the vintage prize.
The answer is TOS ( Tape Operating System ) 1.3 on an IBM 360/20 (T) in 1969. ( Later to be known as HAL).
Ferrous ring memory. 12k. The memory cabinet stood 3'6'' tall by 2 1/2 feet wide by 2 ' deep.
Rotary dials, buttons, and display lights on front of Operators Console ( before VDU's or Visual Display Units).
We had to interpret the lights from BINARY into HEXADECIMAL, perform any calculations we needed to in HEXADECIMAL and re-enter any fix, in Binary again.
We needed to understand, BINARY, OCTAL, DECIMAL, and HEXADECIMAL number bases to operate them.
We would set the input code into the front 'INPUT REGISTER' on the console, which meant that it would have incoming data from Mag Tape, make sure the O/S tape was on Tape Drive 0, and hit INTERRUPT and LOAD. And away it would go.
The oldest computer I wworked on was an ICL 1902, in 1979 ( it must have been 10 years old then) which was 'steam driven'[we called it].
Single components on pc boards ( prior to the micro -chip
).
48k, I think it was or maybe 96k. That's k ( 1,000 bytes) not MB, or GB.
But it got the job done. And It only crashed about once every 3 months or so. ( Remember it was going 24 hours per day, 7 days per week). Only switched off on Xmas Day.
Any way, enough ol' fellas' talk.
Rahim.