[Beowulf] Joe Blaylock's notes on running a MacOS cluster, Nov. 2007

[Peter St. John]

Well it was the 286 I meant; DOS 3.2 on the 286 stopped at 640K, I used
ramdisk, no problem with SVr4. That's all. I'm not blaming M$ for
everything.  I'm sure DOS would have been hard to keep backward compatible,
the unix didn't have to be, it was ported to the 286. DOS caught up later.
Peter

On 11/23/07, Mark Hahn <hahn at mcmaster.ca> wrote:
>
> > XP?) but used all 1.5 MB naturally with the unix (making it clear to
> > me, btw, that the "640K RAM Barrier" was MS's fault, not Intel's).
>
> I'm the last to defend msft, but this 640k thing irks me.
>
> 640k is the physical hardware address of the graphics buffer;
> IBM put it there.  on the 8086/8088, there is no kind of memory
> virtualization, so this is a hard limit on contiguous user memory.
> the 286 is very, very different in memory model (16:16 segmentatation -
> you don't want to know more about it unless you like pain)
> so this location no longer matters to user-space.  of course, code
> assuming only the 8086/8088 model is still 640K-aware.
>
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