2 Oct
2002
2 Oct
'02
6 a.m.
Ok, I've got a friend in academia who wants to know:
What was the first computer to support indirect addressing?
While I expect no definite answer (as if I had asked "what is the first
computer" :-), it should be an interesting discussion.
--
Jeffrey Sharp
2 Oct
2 Oct
9:02 a.m.
Ok, I've got a friend in academia who wants to
know:
What was the first computer to support indirect addressing?
I've taken this to be specifically memory indirect and not the use of index
registers (or "B-lines" - invented in 1949). I would think, perhaps, that
memory indirect was not really feasable until the use of core memory.
Some datum points from manuals found on web.
IBM704 (mid '50s) didn't
GE 625/635 (mid 60's) did
PDP8 (?) did
CDC160A (1961) did
<further searching>
The Manchester Mark 1 (1947-9) had an indirect jump (as well as index
registers) ... this probably takes the prize, then.
Haven't yet found a definitive answer as far as data access is concerned
While I expect no definite answer (as if I had asked
"what is the first
computer" :-), it should be an interesting discussion.
Andy
9:11 a.m.
Jeffrey Sharp wrote:
Ok, I've got a friend in academia who wants to
know:
What was the first computer to support indirect addressing?
I was thinking about the LGP-30, as used by Mel, the Real Programmer.
Did that have indirect addressing, or was it indexed? Mel wouldn't
have used either of those new-fangled inventions, of course.
--
John Honniball
coredump(a)gifford.co.uk
9:26 a.m.
I was thinking about the LGP-30, as used by Mel, the
Real Programmer.
Did that have indirect addressing, or was it indexed?
I'm not sure about the LGP-30, but according to the story, the RPC-4000
did have indexing.
Mel wouldn't have
used either of those new-fangled inventions, of course.
Are you sure you grok the story? The story claims that Mel used indexing.
In general, Mel would have used any available feature of the machine when
it helped him improve his program.
10:37 a.m.
I wrote:
The story claims that Mel used indexing.
OK, correcting myself, the story said that he did indexing by modifying
an instruction rather than using the hardware indexing feature. But
presumably he did this because it was more efficient in the cited
example. In any cases where using the hardware indexing feature was
more efficient, he would have used it.
The point of the story is not "Mel's too old and set in his ways to
use new features." The point is "Mel is an expert on every aspect of
the machine, and knows the best techniques for using it."
7899
days inactive
7899
days old
4 comments
4 participants
participants (4)
-
andyh＠andyh-rayleigh.freeserve.co.uk -
coredump＠gifford.co.uk -
eric＠brouhaha.com -
jss＠subatomix.com