[nSLUG] Cleaning out my desk...
jwark at eastlink.ca
Mon Nov 12 16:33:42 AST 2007
Robin Murray wrote:
> I still have an assembler payroll program I wrote on punched cards when
> I was in school. We had an IBM System/3 which was ancient even back when
> we were using it. The deck's about 4" thick. I think the cards are still
> in order after more than a 1/4 century. I'm feeling old...
Well, you shouldn't be feeling old. The first program I wrote, using
punched cards, of course, was in either January or February 1959 for an
IBM 650 computer. This machine had a rotating magnetic drum memory.
Every instruction had two addresses, the second of which was a "jump"
address - instead of having an Instruction Counter, the address of the
next instruction to be executed was this "jump" address. There was an
Assembler program whose major job was to calculate the jump addresses
based on the opcode of the instruction - depending on the opcode, its
execution time could vary. The idea was to make sure that the drum
memory had rotated just enough so that the next instruction to be
executed was just under the drum's read/write head when it was needed.
I could go on of course but won't bore you any more.
*I* don't feel old - just a bit creaky in the muscles and joints after
two hours of ice skating at the Spryfield Lions Arena twice a week.
Jack Warkentin, phone 902-404-0457, email jwark at eastlink.ca
39 Inverness Avenue, Halifax, Nova Scotia, Canada, B3P 1X6
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