Development, round II

From: Mike Allison <>
Date: Thu Jan 29 11:19:39 1998

SUPER's right, I do believe. The 286 could switch INTO protected mode,
but not out, as I recall. And, there were no virtual '86 modes, as the
386 has in protected mode. Along with a 16MB address space limit
against 4GB for 386.

But these are just the limitations as to why the 286 can't do 386 code.
I don't think theres any reason why the AT couldn't run 286 protected
mode programs as it was the standard around which those codes were

The XT286 seems to bring to mind wome compatibility issues, but I can't
remember what they were. Unless the XT286 was build around 86 support
chips and bios (just to tap 10 or 12mhz speed for XT programs) in which
case you might have some problems.

I guess....


> In a message dated 98-01-29 08:44:40 EST, you write:
> << > I looked in my never used copy of os2 version 1.3 standard edition and
> found
> > no mention of rexx so maybe it arrived in version 2.x but i'm not opening
> my
> > shrinkwrapped version to find out! minimum requirements for 1.3 are a 286,
> > 2meg, and 12 meg of hdd space.
> : Worth a try then. But am I right in thinking that the AT doesn't
> : implement all the 286 modes properly? I'm sure the XT286 doesn't. >>
> AT doesnt implement 286 models properly? i dont get it. AT=80286. now,
> all 286 machines had a limitation about being able to switch from protected
> mode to real mode and back to protected mode without major work and/or a
> reboot. the 386 does this all smoothly under software control. it's also my
> understanding the XT286 is just a regular old 5170 board in a 5160 case.
> david
Received on Thu Jan 29 1998 - 11:19:39 GMT

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