On 9/17/2017 9:56 AM, Paul Carmichael wrote:
El 17/09/17 a las 12:49, nospam escribió:
In article , Paul Carmichael
wrote:

I had an ISA memory expansion board designed for a 386 that I was
able
to get working in the machine and expanded the memory to
16megs...that's
the maximum amount a 286 can address. I did it just for the sake of
doing it.

That said, would it have been possible to put 16 megs of memory
in a 286
at the time it was built, probably only Bill Gates could have
afforded
it!

it might have been possible, but it wasn't particularly useful
because
of segmented memory, a problem inherent to x86 back then.

I was programming back then, and XMS was useful. Not very fast
though. A
lot
faster than MFM hard drives, so better than "virtual memory".

it was still a royal pain in the ass and comparing it to vm is silly.

4k pages. Not that different.

virtual memory is completely different.

x86 didn't get a linear address space until much later.

I was an assembler programmer. Huge pointers were for girls. Real men
used
segmentffset.

then it was even more of a pain in the ass.

My donkey's fine thanks.

Everything had its place and 64k segments were plenty big enough for
most
stuff.

except for stuff that spanned 64k boundaries, like graphics or database
apps.

X86 never got a flat memory model. Actually, I suppose that .com
programs were flat model
in their way :-)

yes it did.


Ok. Kind of. Selectorffset programming felt much like segmentffset
programming. But with giant segments. Why the hell am I talking to you
about programming? I'll stop now.


We have seen more of his programs than his photos.

Oops! I forgot.

--
PeterN