[net.micro.pc] More on PC/XT,comment on 8086

peterr (03/22/83)

----- News saved at Tue Mar 22 00:18:54 1983

A few extra details about the beast:
   There is still an (empty) socket for a co-processor on the mother board.
   No word yet about a faster CPU, so it almost certainly runs as fast as the
   old unit.
   The MicroScribe Winchester drive that IBM uses is somewhat special... it
   uses rack and pinion positioning, a technology that allows for cheaper
   platters at higher densities.

MS-DOS 2.0 is still not available separately in Canada.

General comment on the 8086 and its successors:
  It is interesting to see the slow revolution in software that was prompted
by the 8086's built-in relocation registers.  These relatively simple additions
have opened the door to multi-tasking systems, which are slowly appearing
(Concurrent CP/M, the various UN*X lookalikes, and MS-DOS 2.0).  The next step
will occur with the 80286, 68010, and 16032 which have virtual memory
and protection mechanisms.  Then we'll see demand-paged OS's (introducing users
to the joys of thrashing).  After that, we will see performance enhancements
such as caches.  Whether or not we'll see microcode programmability is an
interesting question.  Ditto for machines designed for distributed systems
(though note that the Z8000 family, designed for high-performance, multi-
processor systems (using chips such as FIFO buffers and very intelligent 
peripheral controllers) never really caught on... perhaps the uP community
has to first get used to multi-tasking and the software techniques used to
handle concurrency).