XTs and large hard disks
fireflyst at earthlink.net
Tue Aug 30 02:23:37 CDT 2005
I'm maxing out the machine for the sake of maxing out the machine.
The portable is a semi-rare beast; it's an XT in a wierd portable
case. I actually bought it as a machine to diagnose car problems
with via the DIACOM software, but I got rid of the car I was using it
on! now it's an experimentation box. I already did the 640K mod to
the mainboard, bought a 2MB EMS card, I have a 1.44MB floppy
controller that works as long as only the MFM disk is in the
system...it won't work with the IDE controller I have, OR the Seagate
What do I have for software on it that I actually USE?
Lotus 1-2-3 2.1
Quicken 6.0 for DOS
IBM PC Storyboard
All the Watcom TCP/IP tools I can find
Overland Data Tools for DOS (for backing the thing up to 9 track
Oh...and I play a few games on it...yes. ;)
I do testing for the MS-DOS Turbo C port of Sarien with it, to make
sure it runs on 8088/8086.
So to say the machine is "lightly used" would be totally wrong. I
beat the silicon out of it.
On Aug 29, 2005, at 10:35 PM, Jim Leonard wrote:
> Wolfe, Julian wrote:
>> 1. Does anyone know a good solution for putting a large drive in
>> an XT,
>> while still leaving it an XT?
> IDE with "540MB" (actual capacity is less) drives or less, if you
> can find an IDE card that works. I have two (different brands) but
> sadly I haven't found time to try them yet in my model 5150. Only
> other solution is SCSI, something I have had extremely unlucky
> progress with (boards with BIOSes won't POST; boards that need
> drivers don't have the damn drivers bundled with the board; etc.)
> However, I believe my experience with 8-bit SCSI on XT is uncommon
> compared with the other gentlemen here.
>> 2. Should I leave the V20 in? I've heard it has compatibility
>> issues with
>> some programs, but I'm not solid on my information.
> The V20 can enable some ill-behaved programs to work as it
> implements the "SHL register,immediate" 80186 opcode, and this
> opcode is sometimes the *only* used opcode used in "286-only"
> programs. I was able to run programs claiming they needed a 286 on
> my AT&T PC 6300 (Olivetti M24 8086 clone) after I upgraded it to an
> NEC V30.
> HOWEVER, the V20 and V30 expand the prefetch queue from 4 bytes to
> 6 bytes (the source of their speedup) and this screws with timing-
> sensitive programs such as games, copy-protected diskette copiers,
> and turnkey stuff like robot controllers, etc. from the early 1980s.
> I'm going to go out on a limb and assume that you're expanding your
> convertable so that it can play most IBM PC games from the
> 1980s. :-) Based on my experience in that context, the V20 will
> cause the following behavior compared to a factory original 8088:
> - 88% of games will run just fine, unaffected by the V20
> - 5% of games will run smoother/better due to the small speedup of
> the V20
> - 5% of games will run too fast to be enjoyable
> - 2% of games will not run at all
> Games are a good example to flush out this kind of behavior because
> they were usually programmed as close to the hardware as possible
> to achieve the best performance; also, many copy-protection schemes
> are timing-based and may fail if the CPU speed is not what is
> If I have incorrectly assumed your intentions, please let me know
> as I'm dying with curiousity :-)
> Jim Leonard (trixter at oldskool.org) http://
> Want to help an ambitious games project? http://
> Or check out some trippy MindCandy at http://
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