1 Mar
2013
1 Mar
'13
11:55 a.m.
Personally, I think the IBM 1620 is a great machine on which to teach
programming. Decimal (none of that nasty binary, hex vs. octal..),
absolutely consistent instruction length (12 digits: 2 opcode, 5 for
each of the two addresses), variable word length (none of this "how many
decimal digits can 32 bits store?". You want a 5,000 digit number?
Fine--it can do it.
No visible registers--it's all memory-to-memory. I/O is very
straightforward (return the carriage on the typewriter, type a number...).
You can type your machine-language program in on the console, hit
"release" and watch it run.
Dijkstra hated the machine, but lots of people learned to program on it.
--Chuck