MIKE ROSS wrote in a message to Roy J. Tellason:

 MR> "Roy J. Tellason" wrote to "MIKE ROSS" (19 Dec
02  20:06:17)  ---
 MR> on the topic of "THOSE OLD EXPENSIVE [2/2]"

 MR> though the hardware was different. For example a lot of programs
 MR> ran well on machines like the Tandy 1000's even though they used an
 MR> 8086. The only real hangup on those was the video which was better
 MR> than the pc's but couldn't be directly written to in the same way
 MR> (i.e. bad for games).

 RJT> That was the thing,  if it wasn't _that_ compatible then it wasn't a
 RJT> clone.  I worked for a bit at a local store that was selling Sanyo
 RJT> machines,  back around the end of 1984,  beginning of 1985.  The acid
 RJT> test was to try and run something that had a reputation for being
 RJT> fussy,  like flight simulator.  Which they did,  only they neglected
 RJT> to mention that they were running a version that was specific to that
 RJT> machine...

 MR> That's it, that early Tandy 1000 also had to run machine specific
 MR> games which naturually used a different way to access the video.

I was at a flea market a while back and actually saw one of those early
T1000 machines for sale!  Dunno which one,  or how much -- I wasn't that
interested. I can still remember stories about things like standard
"full-sized" interface cards not being able to fit into those, 
nonstandard interrupts for things like the HD to make you go to them for
upgrades,  etc.

 MR> A few games would even run under both by offering a Tandy graphics
 MR> option in the startup menu. Hmmm, reminds me the Tandy 1000 also
 MR> had a 3 or 4 voice synthesizer chip for sound which at the time was
 MR> light years ahead of the pc's speaker port bit banging horror. That
 MR> why the Adlib sound card was invented for the PC and later the 
 MR> Soundblaster improved on that.

Reminds me of a kid we had working with us at the shop one time who *made*
a card for his Apple II with a 6581 SID chip on it.  Worked pretty well, 
too.

 MR> The 186 instruction set wasn't too different from the 8086.

 RJT> The big step up with the 186/188 was integrating a lot of hardware
 RJT> that would've been in separate parts on the earlier chips.  I'm not at
 RJT> all sure about the software differences,  and

 MR> You know, I don't think the software was the problem. I think the 
 MR> hex on the 186 was that it fixed the FFF0: segment wrap bug of the
 MR> 8086 which had become the standard method to access expanded 
 MR> memory. 

I really don't know one way or the other at this point.

 MR> Wouldn't it be the kicker if the 286 came out with the bug 
 MR> purposely put back in! Actually all cpu's since... imagine that!
 MR> IIRC there was something else that struck me as odd about the 286
 MR> in that purportedly if one pin was grounded it operated as an 8086.

First I've heard about that,  too.

 MR> I vaguely remember seeing a 40 pin 286 in an XT but being used as
 MR> an 8088.

Oh yeah?  Hm.

 RJT> Even the newest and fastest machines out there these days still look,
 RJT> in large part,  like the earliest,  in terms of how the software sees
 RJT> it.

 MR> Oh, stop it now! You can't run flight simulator 1.0 on a new 
 MR> machine!!! In fact much software became useless when the 386 came 
 MR> out mostly due to timing issues. For example things like the Adlib 
 MR> music card were highly dependant on tight timing delays and these 
 MR> were the first to stop working right under the early software.

I guess I never ran that kind of software here,  then,  because I've never
run into that particular problem.

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