Date   : Mon, 28 Mar 1988 20:57:00 MST
From   : tektronix!midas!copper!michaelk@UCBVAX.BERKELEY.EDU (Michael D. Kersenbrock)
Subject: CPM upgrades, etc.

>Phillip Keen asked for opinions on CPM3.  Here's my two cents:
>I first learned CPM on a CPM3 system.  I found it very clumsy.  I then 
>at the suggestion of several folks 'downgraded' to CPM 2.2.  CPM2.2
>is, to my mind, far more straightforward to use, and definitely a lot
>easier to program for than cpm3.  I rewrote, er, adapted, the BIOS from
>the CPM3 into the CPM2.2 BIOS that I now use.  I then a short time later,
>at the suggestion of the same people, installed ZCPR3 from Echelon.
>It was a straightforward procedure underCPM2.2. It was impossible under
>CPM3. Oh, and I have found compatibility problems between 2.2 and 3.
>Bottom line:  If one is going to use another CCP (highly recommended),
>use your cpm2.2.  I strongly recommend ZCPR3, but there are others.
>I would not even waste my time with CPM3 even if they gave away free
>food with it.
>
>Hope this helps.  E-mail me if I can be of further assistance.
>
>Lee Thomison
>BITNET: OPTON@UHVAX1
>landline: (713) 749-3127


I disagree strongly with this opinion of CPM 3.0.  I started with 2.2
(where I wrote my own BIOS, etc...I did everything down to the nitty
gritty level), and then upgraded to 3.0 (when DRI released it, and I
bought the "generic" upgrade kit).  Documentation was good, and a million
times better than 2.2 .  Performance was also a million times better with
3.0 than with 2.2.  There are SOME incompatiblities, but very few, and
generally not too important.

CP/M 3.0 had most of the improvements that the original MS-DOS "did"
to CP/M. :-)

With the additon of CCP+ (in simtel20...) and full usage/knowlege of the
improvements, I'd say 3.0 is MUCH MUCH MUCH MUCH MUCH better than 2.2.
To tell the truth, my CP/M+ develoment environment looks more like BSD
Unix ("make", grep, VERY compatible library, etc) than CP/M (which I like
BTW).

To give you an idea of what I'm using:

       1) My system is a "homebrew" Z80H one with 1Mb of 0-waitstate
          banked memory (someday with a Z280 if I can't afford an Amiga
          2000 first).  My CP/M+ is the *banked* version.  The *unbanked*
          version may be different in usablity.

       2) My bios (that I wrote) implements 720K of FAST/DMA'd ramdisk
          and about 180K of my OWN floppy-disk cache on top of DRI's
          (didn't fully like their algorithm).

       3) I modified the library of my C-Compiler (Manx Aztec) to
          dynamically check for CP/M 3.0, and if it is "true", to use
          3.0-only features that makes the floppy access (never mind the
          disk cacheing) 3 times faster than 2.2 on the same disks (I
          did many other things to my compiler, but that's another
          story).


Because, however, DRI does not really sell CP/M 3.0 anymore (that I can
tell), 2.2 and ZCPR may be the best choice to go to nowdays from 2.2, but,
the reason isn't because 3.0 is less good, it's just less available.
-- 
Mike Kersenbrock
Tektronix Microcomputer Development Products
Aloha, Oregon