Hybrid DOS – CPM Readme

IAC DOS 3.3 and CP/M Hybrid Disk

This disk is a hybrid which is in part a CP/M type of disk and in part a DOS 3.3 type of disk. It contains files of both types on it, but it does not (yet) bear an operating system.

Like IAC Disk #20 (available from the IAC for $8.00), this disk is a special format designed to assist Apple users whose machines are equipped for more than just the DOS 3.3 operating system.

One of the reasons to use this disk is in those situations in which you might like to work, in one operating environment, on program files which will ultimately be used in another operating system. For example, if you have a modem and terminal program that is capable of operating under DOS 3.3, but you would like to use your CP/M word processor to create or edit text files for transfer, you can use this disk… Write or edit a text file in CP/M using this as a data disk, and then boot up DOS 3.3 (using the BOOT command on this disk). Run the CP/Muffin program to convert the CP/M text file into a DOS text file, and then you are ready to send it over the phone lines.

And of course, you can go the other way as well. You might have a data file from a database program which works in the DOS mode, and you would like to convert it into the CP/M environment so that you can modify and use it with a CP/M-typed database program. Here, you are going to have to use your ‘APDOS’ program or similar. Let me explain some more…

While the CP/Muffin program in the DOS section of this disk is in the public domain (it originated from Call-A.P.P.L.E.), an ‘APDOS’-type program which can convert files from DOS 3.3 to CP/M is not public domain. Therefore, you will have to use your own ‘APDOS’ program and PIP it onto this disk before you can move files from the DOS to CP/M systems.

You can copy this entire disk using the COPYA program from the Apple DOS 3.3 System Master Disk. That means that you can create duplicate copies of this disk – while the files on this disk are not very important, its format could be. Thus, you can delete all the unwanted files from a copy of this disk, and on it the programs and utilities which you like to use.

As this disk indicates when you try to boot it up, it does not contain an operating system on the first three tracks. Instead, it contains a short note telling you about the lack of an operating system. If you would like to put either DOS or CP/M on this disk, it is easily done. To put DOS 3.3 on it, just use the MASTER CREATE program from the DOS System Master Disk. The CP/M operating system can be moved to it by means of the COPY/S command or its equivalent.

For move advanced users of DOS, you may want to use the boot program which is stored on Track 0 Sector 0 of this disk. This 256 byte file turns off you drive motors and prints the message that you see. Here is how it may be of benefit to you…

If you want to remove DOS from a DOS 3.3 disk so that you will have 32 more data sectors, you can do so with the disk editor program contained in the DOS side of this disk. Edit Track 17 Sector 0, the VTOC track, and change bytes $3C, 3D and $40, 41 from 00 to FF. That makes Tracks 01 and 02 free for data storage. You must remember that the disk will no longer boot. Therefore, you can move the 256 bytes from Track 0 Sector 0 on this disk to the same location on your new DOS data disk, so that if you try to boot the disk it will give you an appropriate message. You can even change the message. Starting at byte $3A (which is the 59th byte), you can load in a message up to 189 bytes in length. Make sure the last 9 bytes after the message are: 88 A6 2B BD 88 C0 4C 00 E0 (These bytes turn off the drive motor and put you back in BASIC.)

And now a word about the CP/M files on this disk…

BOOT allows you to boot out of the CP/M environment. It is rather like the PR#6 command in DOS. Just enter the command ‘BOOT’ and then place your new DOS, Pascal (or whatever) disk in Drive 6 Slot 1. Then, hit the for a 16 sector disk or ‘3’ for 13 sector DOS 3.2.

CAT gives a sorted catalog with the file lengths.

CONVERT.BAS is an MBASIC program which will overcome one of the problems with the ‘APDOS’ command -> if you move a text file from DOS 3.3 into CP/M, you will find that it may not print properly. This is because the carriage/returns in DOS are seen as line/feeds only (and not line/feed- carriage/return combinations) in CP/M. Therefore, you may find it necessary to run a text file through this MBASIC program before you can ‘TYPE’ it to screen, print it out, or edit it with a word processor. This MBASIC program is simple enough as it just reads 100 lines from the source text, writes 100 lines to the target text file, then goes back for another 100 lines or until it hits an EOF (end-of-file) marker.

FINDBAD goes through an Apple CP/M disk, checking for bad sectors in the directory or data storage areas.

RPIP is a modification of PIP. It allows you to put in a new disk and reset the drives by entering the letter ‘R’ at the *prompt. Also, you can repeat the last file transfer by using the ‘!’ command.

SAPX will sort a disk directory and re- write it to the disk again.

SQ/UNSQ provides the ability to squeeze and un-squeeze text files. These can be compressed up to 50% or more, depending on their nature. Then, they can be saved to reduce disk storage space, or sent over a modem to another computer (which will have to un-squeeze them). This utility saves time with modem transfer times (and long distance bills!)

SWEEP is rather like the CP/M equivalent of FID, except that it adds more commands. To use it, you go through the target disk’s directory and tag (with the ‘T’) those files you want to move, delete or whatever. Then you use the ‘M’ move command, and you will be asked for the target drive. It is easy to use, so play with a few scratch disks and you will soon become a fan of SWEEP.

TURNKEY allows you to make a CP/M disk into an ‘autostart’ disk, such that when the disk is booted up, it will automatically run a CP/M command file. For example, you can create a disk that will boot up and run the ‘WS’ file to start ‘Wordstar’.

UNERA is a program which will ‘unerase’ (or resurrect) programs which you have deleted, provided that you have not already re-used the disk sectors on which the program was located. Note that UNERA does not use wild- cards, but that you have to specify the name of the erased file exactly.

And now a final plug….

As the person responsible for the IAC’s Disk-of-the-Month, I need submissions from the libraries of Apple user groups. They can be any of a wide variety of program types in a number of operating environments. The programs should be bug-free and (presumably) of a reasonable quality. It is not necessary to submit a disk-full, for just a few programs will suffice. Why not return this disk with a few programs, or how about a hybrid Pascal-CP/M disk ???

Submissions can be sent directly to the IAC office at 908 George Street Santa Clara, CA 95050 or to me, Charles R. Smith 47 Buchanan Drive Unionville, Ontario Canada L3R 4C4

Feedback concerning the IAC’s Disk-of- the-Month is appreciated.


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The A.P.P.L.E. Website is run by the Apple Pugetsound Program Library Exchange Users Group and is open to all Apple and Macintosh fans and their friends.