[Beowulf] Win64 Clusters!!!!!!!!!!!!

Peter St. John peter.st.john at gmail.com
Mon Apr 9 10:29:56 PDT 2007


[regarding the 640K RAM "barrier" of the first IBM PC]

> >
> > Bill Gates says he never said that. In any case, most of that was
> > due to the architectural inferiority of the x86 at the time.


I'm sorry, I've lost track of who is quoting whom :-) but I just wanted to
clarify this about the 640K limit. The Intel 80286 was fine, I ran SVr5 on
it with a memory card giving me 1536 KB. However, to run DOS, I had to
configure the memory past 640K as a Virtual Disk.

I believe the issue was the location in memory of reserved space, stuck at
the back end of the (640K) range, making it awkward to allocate memory to an
application skipping over a reserved segment. So this was purely a MSDOS
issue, had nothing to do with limitations of the 8088 (first IBM PC) much
less the 80286 (on which we ran unix; an option then was Motorolla 680x0 for
some x).

The sufficiency of 640K was merely implied by the design of MSDOS, although
I think IBM would have done better to go after engineering workstations and
just port unix themselves (but that happened quickly because of Open
Architecture).

Peter
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