TRS-80 Model I/III/4:
Frequently Asked Questions

Here are a few frequently asked questions on the Radio Shack TRS-80 Model I, Model III, and Model 4. These are Z-80 based machines that were first introduced in 1977. The three models were partly compatible with one another, and incompatible with most everything else. Today they are of interest only to the nostalgic and a few folks who have specialized applications that were never ported to newer machines. The following are questions that people frequently ask me; your mileage may vary! This FAQ is available on the Web through the page http://www.research.digital.com/SRC/personal/Tim_Mann/trs80.html.

Contents

[1] Where can I get TRS-80 software?

Most software from Misosys, Logical Systems, Galactic Software Ltd., Powersoft, and Breeze/QSD is now available for download by permission of the copyright owner, Roy Soltoff (owner of Misosys). See http://www.research.digital.com/SRC/personal/Tim_Mann/trs80.html.

Other sites with downloadable software include:

Computer News 80 has some commercial software and hardware products, a library of freeware disks, and a small monthly newsletter that still supports the TRS-80 I/III/4. You can contact them via the Web at http://www.computernews80.com/, via email at compnew@trib.com, or by phone at 307-265-6483.

M. A. D. Software deals in TRS-80 products. Among other things, they have upgrades to the Model 4P ROMs and the MODELA/III file (Model III ROM image). You can contact them via email at madcs@madsoft.lonestar.org or via US mail at:

M. A. D. Software
P. O. Box 331323
Fort Worth, TX 76133-1323

Frank Gottschalk ("The TRS-80 Recycler") deals in used TRS-80 hardware and software. You can contact him at 72623.40@CompuServe.COM.

Cord Coslor (Archive Software) is a collector of TRS-80 Model I/III/4 software and hardware who occasionally puts out an electronic catalog. You can contact him at archive@navix.net.

You can still order some software from Tandy Software Replacement and/or Radio Shack Unlimited, formerly Radio Shack National Parts. You can ask at a store or call Radio Shack at 800-843-7422. I'm told that you might have to bug people for a while and maybe ask for a supervisor or someone who's been there longer, before you find someone who believes this is possible and knows how to do it. The purpose of Tandy Software Replacement is to supply replacement disks to people whose originals have been destroyed, so generally they do not provide manuals or packaging, and the prices are very low. They don't actually seem to care whether you originally owned the software. Radio Shack Unlimited also stocks (or can make up) full packages of some software, including manuals.

[2] Where can I get information to repair or upgrade my TRS-80 hardware?

You might find a little information on the Web, but pickings are slim for hardware information. You can start with the TRS-80 links on my Web page, at http://src-www.pa.dec.com/~mann/trs80.html#links.

You can ask on the newsgroup comp.sys.tandy. This is a good place for TRS-80 software questions too. You might also try searching back postings to the group with Deja News.

Also try the software sources given in topic [1] to see if they carry hardware manuals. Frank Gottschalk is a likely source. I don't know if Computer News 80 carries any. Tandy Software Replacement or Radio Shack Unlimited are said to be able to photocopy and sell manuals, but I haven't tried this.

[3] What TRS-80 emulators do you recommend?

People don't really ask me this, but I need to put this information somewhere to refer to from other answers!

Under MS-DOS or MS Windows, I recommend:

Under Unix, I recommend the xtrs Model I/III/4 emulator, version 1.9 or later. This is freeware, available from http://www.research.digital.com/SRC/personal/Tim_Mann/trs80.html. It should work on any version of Unix with the X Window System, except that its support for physical floppy disk drives works only under Linux.

[4] What is a .DSK file?

A .DSK file is an image of a TRS-80 floppy disk in a file. They are used by TRS-80 emulators.

Warning: There are two kinds of .DSK files with different formats, one that originated with Jeff Vavasour's Model I emulator and one that originated with his Model III/4 emulator. Each of Jeff's emulators works only with the kind of .DSK file that was designed for it. Matthew Reed's Model I/III emulator and the xtrs Model I/III/4 emulator work with both kinds of .DSK file transparently.

[5] How can I convert my real TRS-80 floppy disks to .DSK files?

One way is to transfer data over the TRS-80's serial port or printer port. That's probably the best way if you have a Model I, because a stock Model I can read and write only single density, but many PCs cannot deal with single density. Jeff Vavasour's Model I emulator includes instructions on how to do this; see topic [3].

A faster and more convenient way, if you can get it to work, is to read the disks in a PC with a 5" floppy drive. Under MS-DOS or MS Windows, try Matthew Reed's freeware READDISK program. See http://www.arrowweb.com/mkr/readdisk_doc.html.

Alternatively, if you have problems with READDISK or you are using Linux, you can copy the disks with an emulator, as follows.

  1. Get a TRS-80 emulator that supports both .DSK files and real floppy drives. See topic [3]. Read the emulator's instructions and get it running.
  2. Find a PC with a real 5" floppy drive attached. In theory, a 40-track DD drive is best if your TRS-80 had 40-track or 35-track drives, but you can use 80-track HD drives too. (On a PC, 40-track DD drives are usually called 180KB or 360KB drives, depending on whether they are single or double sided.) The trouble with this theory is that DD drives may not work with some emulators. I believe that xtrs should work if you follow the new instructions in the version 1.9 man page, but this is untested; and I have no solid information about other emulators.
  3. Configure the emulator with an LDOS or other operating system .DSK file as drive :0, a new, empty .DSK file as drive :1, and the real drive as drive :2. If you are using a Model I emulator with LDOS, note that Model I LDOS comes on two .DSK files, so configure the emulator with the second one (LDOSXTRA.DSK) as drive :3.
  4. Boot the emulated machine. Model I LDOS requires an extra driver to deal with double density, so if you are using it, type FDUBL to the emulator after booting.
  5. Put the floppy into the real drive and copy it to the emulated drive (.DSK) file. If you are using LDOS 5.3.1, the command is QFB :2 :1. On LS-DOS 6.3.1, the command is DISKCOPY :2 :1. Both those commands format the floppy automatically. On non-LDOS systems, the command might be COPY or BACKUP, and you might need to give extra command line options and/or to FORMAT :1 first; I can't help on that. You might also be able to copy disks by running SuperUtility or the like under the emulator, although programs like SuperUtility have problems running on some emulators.

[6] How can I convert .DSK files to real TRS-80 floppy disks?

There are at least three possibilities:

(A) One way would be to transfer data from your newer computer to a real TRS-80 through its serial port or printer port. That may be the only way if you have a Model I, because a stock Model I can read and write only single density, but many PCs cannot deal with single density. However, I don't know of any software for transferring data to the TRS-80 through a serial or parallel port.

(B) A faster and more convenient way, if you can get it to work, is to write the disks in a PC with a 5" floppy drive. Here is a procedure you can follow.

  1. Get a TRS-80 emulator that supports both .DSK files and real floppy drives. See topic [3].
  2. Get the files working for you in the emulator as .DSK files. Read the instructions for the emulator to find out how to do this.
  3. Find a PC with a real 5" floppy drive attached. In theory, a 40-track DD drive is best if your TRS-80 had 40-track or 35-track drives, but you can use 80-track HD drives too. (On a PC, 40-track DD drives are usually called 180KB or 360KB drives, depending on whether they are single or double sided.) The trouble with this theory is that DD drives may not work with some emulators. I believe that xtrs should work if you follow the new instructions in the version 1.9 man page, but this is untested; and I have no solid information about other emulators.
  4. Bulk-erase a 5" floppy, preferably using an AC bulk tape eraser as sold by Radio Shack and others. You may be able to omit this step if you are using a 40-track drive, but it's a good idea to do it anyway. It is best to use floppies that are rated for double density or quad density, not high density. High density floppies will work in a pinch, but don't expect double density data to stay stable on them for a long time.
  5. Configure the emulator with an LDOS or other operating system .DSK file as drive :0, the .DSK file you want to convert as drive :1, and the real drives as drive :2. If you are using a Model I emulator with LDOS, note that Model I LDOS comes on two .DSK files, so configure the emulator with the second one (LDOSXTRA.DSK) as drive :3.
  6. Boot the emulated machine. Model I LDOS requires an extra driver to deal with double density, so if you are using it, type FDUBL to the emulator after booting.
  7. Put the floppy into the real drive and copy the emulated drive (.DSK) file to it. If you are using LDOS 5.3.1, the command is QFB :1 :2. On LS-DOS 6.3.1, the command is DISKCOPY :1 :2. Both those commands format the floppy automatically. On non-LDOS systems, the command might be COPY or BACKUP, and you might need to give extra command line options and/or to FORMAT :2 first; I can't help on that. You might also be able to copy disks by running SuperUtility or the like under the emulator, although programs like SuperUtility have problems running on some emulators.
(C) If you need a copy of LS-DOS 6.3.1 on a real floppy and have no other way to do it, M. A. D. Software will make a diskette for you for $7.50 US plus shipping. Paper documentation is included. You can request a single-sided or double-sided floppy. This service was announced on 19 January 1998. See topic [1] for contact information.

[7] How can I get individual files off a .DSK file or TRS-80 floppy disk?

Most of the TRS-80 emulators have programs for doing this. Read the instructions for your emulator to find out how to use them. Sometimes the program runs on the emulated Z-80 (a /CMD file); other times it runs on the host operating system (an .EXE file).

Under Jeff Vavasour's Model I emulator, the relevant program is VREAD.EXE. Under Jeff's Model III/4 emulator, it is EXPORT/CMD. Under Matthew Reed's Model I/III emulator, the program is TRSREAD.EXE and is available only with the registered version. Under xtrs, the program is called EXPORT/CMD (not the same program as Jeff's).

[8] How can I put individual files onto a .DSK file or TRS-80 floppy disk?

Most of the TRS-80 emulators have programs for doing this. Read the instructions for your emulator to find out how to use them. Sometimes the program runs on the emulated Z-80 (a /CMD file); other times it runs on the host operating system (an .EXE file).

Under Jeff Vavasour's Model I emulator, the relevant program is VWRITE.EXE. Under Jeff's Model III/4 emulator, it is IMPORT/CMD. Under Matthew Reed's Model I/III emulator, the program is TRSWRITE.EXE and is available only with the registered version. Under xtrs, the program is called IMPORT/CMD (not the same program as Jeff's).

[9] What do I do with TRS-80 software that comes in .ZIP files?

Some TRS-80 software you will find on the Web is supplied in .ZIP archive files. You need to unzip these files to unpack their contents, and you'll generally need to do this on your PC or Unix box, not your TRS-80 (or emulated TRS-80). You can get free unzip programs from http://www.cdrom.com/pub/infozip/.

Within some .ZIP archives is a .DSK file. This is an emulated floppy disk file. See topic [4] and the rest of this FAQ for instructions on how to deal with .DSK files.

Other .ZIP archives contain individual files extracted from TRS-80 disks. You can use these with an emulated (or real) TRS-80 by copying the files onto a .DSK file or a real floppy. See topic [8] for instructions.

Some .ZIP archives of TRS-80 software may contain both a .DSK and the individual files extracted from it. This is perhaps the most convenient form, but obviously takes up twice as much space as either of the others.

** End of TRS-80 Model I/III/4 FAQ **