[nSLUG] Cleaning out my desk...

Jack Warkentin jwark at eastlink.ca
Mon Nov 12 16:33:42 AST 2007


Hi Everybody

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.

Regards

Jack

Jack Warkentin, phone 902-404-0457, email jwark at eastlink.ca
39 Inverness Avenue, Halifax, Nova Scotia, Canada, B3P 1X6



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