"Roy J. Tellason" wrote to "MIKE ROSS" (18 Dec 02  20:06:09)
 --- on the topic of "THOSE OLD EXPENSIVE [2/2]"

 >RJT>  Anyhow,  TeleVideo took a different

 MR> Oh, ya, just recalled a Televideo board as the only I've ever seen
 MR> an 80186 used in. IIRC it also used 32 x 64256-12 drams for 4M???.

 RJT> There were a few 186 (and maybe even 188) machines out there,  but
 RJT> what happened was that early on it became *imperative* that the
 RJT> 8088-based stuff be "pc-compatible".  There were a few
machines that
 RJT> weren't,  and they disappeared in short order.
 RJT> Unfortunately,  IBM in the design of that machine chose to use some
 RJT> interrupts that intel had called "reserved",  which came into play
 RJT> with the 186/188 chips,  that's why those were never used all that
 RJT> much.
 RJT> The boards that did sell were for people who wanted a more powerful
 RJT> machine, and didn't care too much about pc compatibility,  not a very
 RJT> significant portion of the total market.

I just looked through my memory trays to check the part numbers of the
drams and they were TMS4256-12 (TI). However, they are 16 pin not 18. So
these are probably equivalent to 41256 drams not the 64256. The board
then had 1Meg not 4M as I mistakenly thought.

The 186 instruction set wasn't too different from the 8086. There were
only a couple significant instructions such as PUSHA and POPA which
would save and restore all the flags and a few to handle multiple
frames, multiplication in memory, and indexed string I/O. The resulting
machine would still have been quite compatible even though the hardware
was different. For example a lot of programs ran well on machines like
the Tandy 1000's even though they used an 8086. The only real hangup on
those was the video which was better than the pc's but couldn't be
directly written to in the same way (i.e. bad for games).

 Mike
 ****

... That was a fascinating period of time for electronics
--- Blue Wave/DOS v2.30