27 Jul
2023
27 Jul
'23
7:16 p.m.
From: Greg 'groggy' Lehey
Interdata had instruction sets that were close to the
IBM instruction
set, but my recollection was that they were different enough that IBM
software wouldn't run on them.
Bitsavers doesn't have a wealth of Interdata documentation, but there is some:
http://bitsavers.org/pdf/interdata/32bit/
Someone who's familiar with the 360 instruction set should be able to look
at e.g.:
http://bitsavers.org/pdf/interdata/32bit/8-32/8-32_Brochure_1977.pdf
and see how compatible it is.
Noel
27 Jul
27 Jul
8:33 p.m.
New subject: What Happened to Interdata?
On 7/27/23, Noel Chiappa <jnc(a)mercury.lcs.mit.edu> wrote:
Someone who's familiar with the 360 instruction set should be able to look
at e.g.:
and see how compatible it is.
Thanks for the pointer. I took a quick look. My knowledge of the
S/360 instruction set is very rusty at this point--it's been over 40
years since I programmed in it.
The program status word (PSW) format looks very familiar. Both
architectures seem to support 24-bit addressing.
Interdata has some data types and instructions for manipulating them
not present in S/360. Circular lists, for example, and instructions
for CRC calculation.
I didn't see anything about packed or zoned decimal support.
So perhaps an extended subset of S/360. I'd have to do a side-by-side
comparison between this document and S/360 Principles of Operation to
determine the level of binary program compatibility, if any. But it
looks like it might be better than the HitchHiker's Guide to the
Galaxy adage: "almost, but not quite, entirely unlike tea."
-Paul W
28 Jul
28 Jul
3:38 a.m.
New subject: What Happened to Interdata?
On Thursday, 27 July 2023 at 16:33:54 -0400, Paul Winalski wrote:
On 7/27/23, Noel Chiappa
<jnc(a)mercury.lcs.mit.edu> wrote:
Yes, it's possible that both Interdata and RCA/UNIVAC/ICL instruction
sets are supersets of the /360 instruction set. The only one I still
remember is the LI (load immediate) instruction. The /360 did the
same function with LA (load address), but IIRC that was RX (4 bytes),
while LI was RR (2 bytes).
Someone who's familiar with the 360
instruction set should be able to look
at e.g.:
and see how compatible it is.
Interdata has some data types and instructions for manipulating them
not present in S/360. Circular lists, for example, and instructions
for CRC calculation. I didn't see anything about packed or zoned
decimal support.
So perhaps an extended subset of S/360. I'd have to do a side-by-side
comparison between this document and S/360 Principles of Operation to
determine the level of binary program compatibility, if any. But it
looks like it might be better than the HitchHiker's Guide to the
Galaxy adage: "almost, but not quite, entirely unlike tea."
Yes, that seems reasonable. My guess was that binary compatibility
wasn't a big issue in those days, since nearly all applications
software was written only for specific installations. And of course
licensing issues would preclude running IBM OS on the other machines.
Greg
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4:18 p.m.
New subject: What Happened to Interdata?
On 7/27/23, Greg 'groggy' Lehey <grog(a)lemis.com> wrote:
My guess was that binary compatibility
wasn't a big issue in those days, since nearly all applications
software was written only for specific installations. And of course
licensing issues would preclude running IBM OS on the other machines.
That certainly was true for S/360 in the 1960s. IBM bundled its
software offerings with its hardware. If you leased an IBM S/360, you
got the development toolset (compilers, link editor, assembler) for
free, as well as utilities such as sort/merge. Source code for the OS
and the utilities was readily available in microfiche form. There
were very few thrid-party software offerings. One that sticks in my
mind is SyncSort, a sort/merge utility that far outperformed IBM's
sort/merge program. If you were a big S/360 data center doing really
serious, high-volume stuff, you used Storage Technology tape drives
and SyncSort.
That all changed when a 1969 antitrust complaint caused IBM to
unbundle its software from hardware. Before, you got the software for
free as part of your hardware lease. After, you had to buy a separate
license for each software product.
-Paul W.
286
days inactive
287
days old
3 comments
3 participants
participants (3)
-
Greg 'groggy' Lehey -
jnc＠mercury.lcs.mit.edu -
Paul Winalski