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VISICALC IS A TRADEMARK OF PERSONEL SOFTWARE INC LAZY WRITER IS A TRADEMARK OF ALPHA BIT COMMUNICATION SCRIPSIT, SUPERSCRIPSIT, PROFILE III PLUS AND TRSDOS ARE TRADEMARKS OF TANDY CORP LDOS IS A TRADEMARK OF LOGICAL SYSTEMS INC NEWDOS8O IS A TRADEMARK OF APPARAT INC DOS PLUS IS ATRADEMARK OF MICRO-SYSTEMS SOFTWARE INC MULTIDOS IS A TRADEMARK OF COSMOPOLITAN INC VIC 20 AND COMMODORE 64 ARE TRADEMARKS OF COMMODORE BUSINESS MACHINES, INC.,
CP/M 2.2 on the Models 11/12/16
Terry R. Dettmann, Associate editor
Many Model 11/12 owners use TRSDOS exclusively. Primarily because when they bought the system, TRSDOS was included. That is a powerful incentive, but is it enough?
One of the purposes of this article is to answer that question. Is CP/M really better as some claim? How about the availability of programs for CP/M? Are the Model 11/12 CP/M's as good as, better than, or worse than TRSDOS?
I must point out that I have seen, and used, the Pickles & Trout version before. I really liked it then and I like it now. When I last reviewed 8-inch CP/M systems, (May/June, 1981 -Ed), Pickles & Trout CP/M got my vote.
The Pickles & Trout and Aton CP/M's submitted for this review arrived only weeks ago. I haven't really been able to wring out either version as well as I did the older version of Pickles & Trout CP/M.
For many, CP/M is not just an operating system, it is the operating system. As with some programming languages, CP/M has achieved almost cult status. But, by and large, most people who use CP/M use it for practical reasons. It works, it's versatile, numerous programs are available for it, and 8080/Z80 systems can, in general, share software written to work under CP/M.
All this sounds wonderful, right? To see just how wonderful, let's look at how CP/M is put together. CP/M's Basic Structure 20 Basic Computing
CP/M is built from three parts: the Console Command Processor (CCP), the Basic Disk Operating System (BDOS), and the Basic Input/ Output System (BIOS). Each part has a special purpose.
Users interact with CP/M through the CCP. It displays a prompt for input and waits for a command line to be typed. Once the command line has been entered, the CCP looks to see if it is a built-in command.
There are six built-in commands in the CCP:
TYPE: Types out the contents of a file to the screen.
DIR: Lists the directory of files on the current disk.
REN: Renames a file.
ERA: Erases a file.
SAVE: Saves a machine language program to a disk file.
USER: Allows multiple directory areas within a single directory.
If the CCP can't find the command among those that are built-in, it looks to the current disk to see if there is a command file (ends in '.COM') which matches the command name.Most CP/M systems include the following command files:
SYSGEN: Generates a new CP/M system.
ED: A line-oriented editor for program development.
PIP: A file-copy utility.
ASM: An assembler for 8080 code.
LOAD: Loads an assembled file into memory.
DUMP: Dumps the contents of a file
DDT: A machine language debugging tool.
SUBMIT: A batch command utility. MOVECPM: Reconfigures CP/M in memory.
STAT: Displays and alters device assignments.
If a command file is found, it is loaded into an area of memory called the TPA (Transient Program Area) and then executed.
While a program is executing, whether it is the CCP or a command file, input and output is handled by calls to the BIOS. The BIOS provides a series of subroutines for primitive level operations on the keyboard, video screen, and so forth. If you were to buy a CP/M system directly from Digital Research Inc., you would have to write the BIOS for your system. Luckily, this is normally done by systems houses who market the systems. Aton and Pickles & Trout are supplied ready to use with the TRS-80 Models II, 12, and 16.
The BDOS handles file system operations, providing services to the CCP in getting file information and managing it.
All put together, the modules of CP/M make a very powerful tool for controlling a small system.
Aton and Pickles & Trout CP/M
Both of these CP/M's are full function operating systems, though some of the standard functions have been replaced, or supplemented, in various ways. All of these replacements were improvements of one sort or another.
The Pickles & Trout distribution disk had the command files listed in Table 1 included on the disk. The Aton command files are listed in Table 2. They each cover almost everything you might want to do.
The systems performed well in the limited testing I was able to do. I had more difficulty getting used to the Aton version, but the fault was more mine than theirs.
The utilities for each system were run and each system showed no noticeable failure. The systems were tested on a plain Model II and I didn't check out double-sided, hard disk, nor extended memory abilities. I am working on them and will report any interesting results.
My major complaint is with the transfer programs for TRSDOS. I realize that the intention of both Aton and Pickles & Trout is to sell you on CP/M, but there are times you just might go back to TRSDOS. The utilities should go the other way too!
One of the most significant parts in any software package is the documentation. Both Aton and Pickles & Trout put together quite reasonable documentation. Pickles & Trout specifically pointed out that their documentation is being rewritten. The present form is quite choppy since it has simply been extended, not rewritten, over the last several revisions and is pretty hard to read.
Neither system's documentation is really for the beginner. Aton has a nice beginner's manual for Omniwriter, but the system manual is skimpy. Both systems provide a copy of the Digital Research, Inc.'s operating system manual. Any of you who remember the old Digital Research Inc.'s manuals will be very impressed by the improvement in this one. Also included with each system is a small reference book for CP/M commands from Digital Research, Inc.
I like the Pickles & Trout manual somewhat more because I felt it explained things better, but since it was out of date and being updated, it was tough to use. The sample of their new style (the double-sided diskette manual) was a significant improvement.
How About Programs?
One of the major questions I hear concerning CP/M is "Is itreally true that there are thousands of programs available for CP/M?" The major point raised in advertising seems to be the availability of programs for CP/M that will do practically anything.
Well, the answer is substantially true. For example, through the users groups you can get a wide variety of programs that were written for the CP/M environment. I have a disk from the CP/MUG with many terminal programs on it. There's some pretty good stuff there. MODEM7, one of the programs on the disk, is a good smart-terminal package.
There's one important note to be made about the disk. The programs are all tailored to particular modems and other equipment, and all are in assembly language. If you're comfortable with that, great! If your knowledge of assembly language is skimpy to nil, this is not the disk for you because you will probably have to modify and assemble the program to make it work. (Well, what did you expect from user group software?)
That isn't the case with all user group software. You can get some in BASIC, other languages, compiled, assembled, or ready to work with an assembler. However, don't expect this to solve all of your problems.
Even more, you should realize that software like this comes without a warranty. There's no guarantee that the software doesn't have bugs. It also varies in quality; some is professional, some far less.
So, the answer to the question of availability of programs is both yes and no. Yes if you are a hobbyist who is willing to look for the gems and do your own modifications. No or maybe if you're just looking to buy ready-made software.
If we move out of the user group arena and look at professional packages that are available, there is definitely much to choose from. There are more languages, more accounting packages, generally more of everything, running under CP/M. However, just saying that there are more doesn't make them better.
The major mistake that people make in choosing systems (both computers and operating systems) is to get the system first and then go looking for the software to do the job they want done. The emphasis should be the other way around. First look into the applications you want. Find one and then buy the computer and operating system that runs it.
If what you want is to get a job done, it's likely (but not certain) that you'll find it running under CP/M. But first find the program, then get the CP/M.
To play with new languages, interesting programs, or just learn new systems, by all means, get CP/M. It will give you more flexibility than TRSDOS.
Is CP/M Better Than TRSDOS?
That is a loaded question. There is no way to answer it without drawing fire from someone. CP/M has many die-hard adherents. That's great, it deserves its reputation. But is it really better?
When it was first released, it had its problems, just like TRSDOS did. Now, TRSDOS 2.0 and later versions are really pretty good. CP/M 2.2 and later versions are also stable and well-tested. But better?
My feeling is that neither one is better than the other. It is too subjective. I've had a lot of success with both TRSDOS and CP/M. CP/M does somes things better than TRSDOS (e.g. it gives you more information on the system and gives you more ability to use it in the manner you choose).
There are a number of books (see the listing of sources) that will help you do very advanced things with CP/M. The same operation would be very difficult to do with TRSDOS. CP/M is just another way of working with the system.
What Do I Recommend?
In the final analysis, CP/M should be chosen for the reasons given above. If the job you want to do can be found there, get it.
I highly recommend either Aton or Pickles & Trout CP/M. Each has the same basic capabilities at least as far as I was able to test them for this review. Both companies offer some nice features. I am hard-pressed to choose between them.
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