In <[EMAIL PROTECTED]>, on 12/12/2006
at 02:41 PM, "Patrick O'Keefe" <[EMAIL PROTECTED]> said:
>Back in the olden days (like the late '60s) IBM had good samples of
>each, and the destinction was very clear. S/360 customers had to
>run 1401 programs, and IBM provided the ability to do that on some
>S/360 models.
So far so good.
>The Mod 30 had a 1401 emulator. You ran a configuration deck into
>the system and the microcode allowed the hardware to execute 1401
>code.
No. The Compatibility Initialization Deck (CID) was a S/360 program.
It used normal S/360 instructions along with instructions added by
the[1] emulator feature. Otherwise COS would have been impossible.
That was true for the 360/30, the 360/40 and the 360/50.
>I don't remember what operating system)
None, at least until COS came along; then it was DOS/360.
>Thos 2 samples both gloss over tons of details,
The Devil is in the details. 1401 emulation worked basically the same
on the 2030 and the 2040.
An additional bit of confusion is caused by the fact the for the low
end S/370 systems IBM provided a program that they called a 1401/1410
emulator that would use an installed emulator feature to speed of
simulation but that would also run on a system without the emulator
feature.
[1] The details were different on different models. AFAIK every[2]
emulator feature on every model included an instruction called
Do Interpretive Loop (DIL), that was the heart of the emulator
feature.
[2] Not counting the DOS Emulator feature on the low end S/370's.
--
Shmuel (Seymour J.) Metz, SysProg and JOAT
ISO position; see <http://patriot.net/~shmuel/resume/brief.html>
We don't care. We don't have to care, we're Congress.
(S877: The Shut up and Eat Your spam act of 2003)
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