Re: Computing Editorial (please read)

[pausch@saaf.se (Paul Schlyter)]

In article <3E2A2CA1.6030507@noneofyourbusiness.com>,
Exegete  <millers@noneofyourbusiness.com> wrote:
> Charles Richmond wrote:
.........................
>> By the time that the C-128 was introduced, Mess-DOS
>> was already making enroads into the CP/M marketplace. If
>> people wanted to run CP/M, they would run it on an IBM PC
>> by that time.
> 
> Few people would run and and spend $3,000 for an IBM PC/XT
> just so they could run CP/M - esp. since they had to buy
> extra hardware in order to be able to do that.
 
Depends on WHICH version of CP/M you wanted to use.  Although you
needed extra hardware to run CP/M-80 on the IBM PC, CP/M-86 ran on it
without extra hardware.  The early IBM PC offered a choice of three
different OS'es: MS-DOS, CP/M-86 or UCSD Pascal.  I know of some
software developers around 1981-82 who used the UCSD Pascal platform
on the Apple II with the explicit purpose of being able to easily
port their application to the IBM PC, where they envisioned UCSD
Pascal to also become an important OS.
 
Some years later, the NEC V-20 CPU appeared, which was a plug-in
replacement for the 8088 CPU of the IBM PC.  The NEC V-20 offered the
instruction set and instruction speed of the 80186/188 (most notably
3 times faster mult/div instructions) and also an 8080 emulation
mode, which enabled you to run CP/M-80 code as native code instead of
emulated code.  Some CP/M-80 emulators for the PC utilized this,
and they ran CP/M-80 programs some 4 times faster on a 4.77 MHz
V-20 equipped XT than on a 20 MHz 386.... one needed a 66 MHz 486
to have the emulation run as fast as the 4.77 MHz V20.
 
-- 
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