Re: Cycles per ASM instruction

Sven Pran wrote:
> At one time I visited our sister company in England for information on
> an engineering program they were using. It required OS PCP (the first
> primitive version of IBM OS?) and I was told that this could be run on
> our 360/30 if we installed an RPQ extending the core memory to 96KB.

Actually, OS/360 PCP could run on as little as 32KiB, although you 
needed a 64KiB system to install it with.

> I don't think we ever tried that on the 360/30 because I do remember our
> system programmer stating that there was little sense in running OS on
> anything with less than 250KB! (We got ourselves a 360/40 instead)

I /did/ run OS/360 on a 64KiB 30, though chiefly in preparation for 
future use on a 256KiB 40. PCP was painfully slow, and had no SPOOLing, 
but it worked.

-- 
John W. Kennedy
"The blind rulers of Logres
Nourished the land on a fallacy of rational virtue."
   -- Charles Williams.  "Taliessin through Logres: Prelude"