Date   : Fri, 31 Jul 1992 12:02:34 GMT
From   : wupost!waikato.ac.nz!aukuni.ac.nz!kcbbs!kc@uunet.uu.net (Richard Plinston)
Subject: Re: CP/M operating sys for intel machine

   >>> I believe that CP/M-86 evolved into the MS-DOS compatible DR-DOS

   CP?M-86 went many ways.  CP/M-86 for IBM-PC (pre-XT) was released
   about March 82, it was upgraded mid-83 to support XT with hard
   discs.  Early MS-DOS also did not support hard drives.  It was
   replaced as a product by Concurrent-CP/M-86 in mid 83.  This allowed
   multi-tasking by having 4 'virtual screens' thus 4 tasks could run
   simultaneously.

   CCP/M developed to include the ability to run MS-DOS programs as
   Concurrent-PC-DOS (3.2) in Sept 84.  This system was also multi-user
   (as well as multi-tasking) allowing terminals to be attached to a
   multi-port card.

   It has developed through CDOS, CDOS-386, to now being DR-MultiUser-DOS
   5.1.  DR-MDOS still retains CP/M-86 and MP/M-86 compatability in
   its 'native mode' API.

   DR-DOS was originally built from the CDOS source code by removing the
   multi-user, multi-tasking and CP/M-86 compatability parts to produce
   DR-DOS 3.41.  I understand that DR-DOS 6.0 and DR-MDOS 5.1 still have
   some common source code.

   There were other DR 'replacements' for CP/M-86.  DOS+ in the mid-80s
   was a MS-DOS 2.x clone that also ran CP/M-86 programs and had limited
   multi-tasking abilities.  It was bundled with Amstrad 1512 and 1640
   machines - though MS-DOS was also included.  It also came with the
   ACORN 80188 co-processor for the BBC Master 128/512 (for students of
   the esoteric the BBC Master 128 was a 6502 based 128Kbyte machine,
   the co-pro was just a 80188, 512Kb of memory, couple of ROMs that
   plugged into the 'tube' to give MS-DOS compatability - I still have
   one).