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From: towson%amsaa@sri-unix.UUCP
Newsgroups: net.micro
Subject: Re:  TRS-80 Model III CP/M?
Message-ID: <15358@sri-arpa.UUCP>
Date: Mon, 9-Jan-84 12:24:45 EST
Article-I.D.: sri-arpa.15358
Posted: Mon Jan  9 12:24:45 1984
Date-Received: Sun, 15-Jan-84 05:53:28 EST
Lines: 38

From:      David Towson (CSD) <towson@amsaa>

I agree wholeheartedly with the comments from decvax!genrad!john@ucb-vax
concerning the goodness of TRS-80 operating systems such as NEWDOS80 and LDOS.
Those two operating systems are quite sophisticated.  They offer all of the
features of standard CP/M, allow a degree of I/O redirection, will support
all sorts of disks, and will search all available disks automatically looking
for a requested program.  You can also switch disks at will for read or write
without incurring the maddening abort "BDOS ERROR R/O" which CP/M'ers have come
to hate.  Both of the OS's mentioned are well supported, and there is a large
available software base.  The only caution that I would offer is that, unlike
CP/M programmers, those for TRS-80 dos'es are not as well disciplined about 
doing I/O through the operating system.  The result is that direct control of 
the disk controller, and to a lesser degree direct reading of the keyboard make
programs written for the Model I unusable on the Model III (those programs that
are written using direct control, i.e., not through the dos, that is).  But the
two operating systems mentioned are quite good.  I have worked with at least 11
different operating systems for the Model I (which is what I have) including
both base-0 and base-4200 CP/M.  I spent several years using non-CP/M dos'es.
I now use CP/M almost exclusively for the simple reason that there is a huge
amount of good, free software available for the downloading via the Defense
Digital Network.  I guess a secondary reason is that I get myself all wrapped
around the axle when I switch dos'es after not using one for a while.  (Yester-
day, I even had to think a minute to remember how to enter a NEWDOS copy 
command for a disk backup.)  Finally, the above writer's comment concerning the
non-usability of CP/M programs written for a base-0 environment when you have a
base-4200 (remapped CP/M) system is an important consideration.  Fortunately,
the public domain software generally comes with source code, and can be re-
assembled for the different bases.  Many programs even have assembly switches
built in.  However, one cannot assume that all programs will have source code
available to the public.  This is particularly true of the most desirable
commercial programs.  In choosing between a TRSDOS-like dos and CP/M (either
remapped or standard), one would be well advised to investigate the cost and
availability of the particular needed applications software as well as the
other obvious costs.

Dave Towson
towson@amsaa