Possible to speed up I/O subsystem of 5150?

From: Jim Leonard <trixter_at_oldskool.org>
Date: Thu Dec 16 00:35:52 2004

Hans Franke wrote:

> I may have to disagree. Without EMS, XTs don't have more than
> 992K of RAM. At least my XT systems did usualy offer at least
> 704K of continous RAM plus whatever was possible between the

You must have had a clone where system RAM and video RAM shared space, like a
Tandy 1000 or Amstrad. Regular IBM 5150 had usuable memory for the first 640K,
and then you could "use" the video RAM on a Hercules or CGA card if you were in
text mode and only using one page, but that was it.

> cards. The 704K where supported by default, while for the mem
> inbetween a little programm at startup to relink the memory
> had to run. works fine wit ANY dos version.

Only on your hardware :)

> If you had a VGA in your XT (8 Bit VGA was available), some
> 736K (708 as largest chunk) where possible without any addon
> memory card, if you restricted yourself to colour (or 704+32K
> when using Monocrome :)

Now I think you're confusing XTs with 386s -- Once the 386 was out, you could
remap how memory was laid out. I remember getting 736K of DOS RAM using
Quarterdeck's QEMM on my 386/16 with a VGA card... but that wasn't possible on
an XT.

> And speaking of cache utils, there where quite some available
> for DOS, that could run on XTs - all you had to do is give up
> main mem :)

Yep, tried that too :-)
Jim Leonard (trixter_at_oldskool.org)                    http://www.oldskool.org/
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Received on Thu Dec 16 2004 - 00:35:52 GMT

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