Jeff Vavasour's TRS-80 EMULATION Page
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Level I BASIC in a browser

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TRS-80 Model I

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TRS-80 Model III/4

TRS-80 CoCo 2

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TRS-80 CoCo 3

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Timex/Sinclair 1000 in a browser

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General History of Jeff's Emulators About ROMs Links
The M.I.C.E. Project:
The World's Most Ill-Conceived Emulator
Send email to Jeff Vavasour.

Except for the Online T/S 1000 and BASIC in a browser, all emulators shown here are for use with MS-DOS.


TRS-80 Level I BASIC in a browser (Java)

Go directly to the TRS-80 Level I BASIC Simulator now

Browse the Software Library of ready-to-run programs for the Simulator

Read more about the Simulator on thte Help Page

Download an older MS-DOS version of Level I BASIC (this version does not include enhancements of the browser version)

  If your browser supports Java, you'll be able to write a BASIC program directly in your browser! This is an adaptation of my earlier TRS-80 Level I BASIC Simulator into Java. This Java version (in theory) will run on any computer in any browser that supports Java and JavaScript. As it is not an emulator, but rather a recreation, I took the opportunity to add a couple additional features including colour support.

I did this project for several reasons. Computers these days have made programming inaccessible to the average person. I wanted to reclaim the "old ways" a bit, where a person could tinker, learn and share what they've found. I chose a simple BASIC like Level I BASIC because I wanted something easy for people to learn.

Also, I've put up a Software Library page. To start out, I've put three programs there, but I invite everyone to try out this new BASIC and submit their own programs written in this browser-based Level I BASIC Simulator. If you choose to submit something, your program will be added to the library page (after it has been reviewed) so that they can be shared with others. This Software Library has the same philosophy as the 80's computer hobbiest magazines like SoftSide, 80 Micro, etc.

I did this project as an experiment. I like to stay up to date on current technology, and hadn't really had the chance to explore Java or JavaScript in depth yet. (To be honest, my initial impressions weren't good, but I thought I'd do a real project before judging too hastily.) Internally, this simulator was written pretty oddly. I wrote QuickBASIC-based tools to auto-translate my MS-DOS-based version into C which was then brought over to Java as a starting point. This is the initial release, so there may be bugs. In fact, it may not work at all in some browsers or on some computers. To that end, if you are having problems, check out the reporting a bug section of the Simulator's help file.


TRS-80 Model I Emulator (freeware)

Download the complete TRS-80 Model I Emulator Version 3.02u

Supplement package only (for users who've already installed an older version 3.x)

Documentation on the supplement package

Source code for TRS-80 Model I Emulator Version 3.02u

  The TRS-80 Model I was the first computer I attempted to emulate back in December of 1989. The emulator evolved between then and 1997, ultimately arriving at the state you find here. The Model I Emulator was, for a time, a shareware product; however, the registered version has been discontinued and the unregistered Version 3.02u is all that remains. Out of respect to those that have paid for the registered version, I will not be releasing the final registered version (Version 3.01r) or its source code for distribution.

The emulator simulates a 48K TRS-80 Model I with 4 disk drives, printer, RS-232 board, and cassette drive.

UPDATE Release G includes the following new features:

  • Optionally run the emulator on modern PCs at the same speed as the original Model I regardless of the speed of your computer.
  • Optionally disable the RS-232 emulation, which caused occasional lockups on some computers.
  • Improved Windows XP support over Release F when running at original TRS-80 speed.

Full details on the upgrade can be found here.

Previous users (including registered version): If you are a user of a previous version of my Model I Emulator, you need only download the supplement package and unzip it to the directory containing your copy of the Model I Emulator.

For the curious, if you have a working knowledge of 16-bit Intel assembly, the source code for the TRS-80 Model I Emulator version 3.02u and the supplement package is now available for download here.

Note: this is an unsupported product.


TRS-80 Model III/4 Emulator (commercial)

TRS-80 Model III/4 Emulator Manual in PDF format (or view the text version)

Download Virtual Disk Utilities to read TRS-80 disks for use in emulators

ADDENDUM to TRS-80 Model III/4 Emulator Manual, Version 2.4

View screen shots of the Model III/4 Emulator

  My TRS-80 Model III/4 Emulator was a commercial product distributed by Computer News 80 from 1993 to 2009. Sadly, with the passing of Computer News 80's proprieter, Stan Slater, in August of 2009, Computer News 80 has ceased operation. My TRS-80 Model III/4 Emulator was an MS-DOS based product, a platform that, in itself, is also obsolete. Likewise, the hardware needed to access TRS-80 disks (at least, the 5 1/4" variants) is becoming scarce, as well. Technical support becomes more difficult.

Out of respect for those that purchased the emulator, I will not presently be making the program available for download. For those needing a TRS-80 Model III/4 Emulator, there are a number of other emulator solutions that have appeared in more recent years, some of which are suited to modern operating systems. Ira Goldklang's TRS-80 Revived Pages is a good resource for those interested in TRS-80 emulation.

If you'd like more information on the features and functionality of this emulator, you can read the documentation.

The emulator's virtual disk utilities may be of use with the various TRS-80 emulators out there. These utilities will allow a properly-equipped PC to convert TRS-80 floppies into the virtual disk format used by the emulator, and back. See Section 2.1 within the manual for details on how to use these utilities.

BUG FIX: It has been reported that some newer generation video cards show improper colours when the emulator is put into CGA mode and the monitor colour is set to green. If you are experiencing this problem, download this patch program, save it in the directory with the emulator, and type "GREEN MODEL3.EXE" or "GREEN MODEL4.EXE" to patch the appropriate emulator. (Thanks to Mark Fishman for testing this solution.)

Note: this is an unsupported product.


TRS-80 Colour Computer 2 Emulator (freeware)

Download the CoCo 2 Emulator version 1.6

Download older version 1.3 release of RETRIEVE and DSKINI

Source code for CoCo 2 Emulator version 1.6 and RETRIEVE/DSKINI version 1.3

  My TRS-80 Colour Computer 2 Emulator will run original CoCo as well as CoCo 2 software. As with all the emulators here, the system requirements are very modest by modern standards (16MHz 286 or better, 256K RAM, EGA or better graphics). Some modern 3D video cards have dropped support for EGA graphics, so there may be compatibility problems.

UPDATE: Version 1.6 new features include:

  • Set the emulator to run at the CoCo's original speed regardless of the speed of your PC using the new "Original Speed" option under the F6 Options Menu.
  • Improved Windows compatibility; no more MS-DOS mode warnings.
  • CASOUT can now convert virtual cassette files to .WAV files instead of just outputting straight to your SoundBlaster. (Good for non-standard audio cards and fast computers which have problems with CASOUT.)
  • Horizontal sync interrupt now supported.

Also available: Older version 1.3 releases of RETRIEVE and DSKINI for those having trouble with the ones that are in the version 1.6 package.

It's been noted on bit.listserv.coco that RETRIEVE and DSKINI may not work with 360K 5 1/4" drives unless you set your PC's BIOS to (mis-)identify the drive as a 720K 3 1/2" drive instead. If you are having difficulty with both versions of RETRIEVE/DSKINI, this is another option to try. Consult your PC's motherboard manual for details on BIOS configuration.

For the curious, if you have a working knowledge of 16-bit Intel assembly, the source code for the CoCo 2 Emulator version 1.6 as well as the version 1.3 releases of RETRIEVE and DSKINI can now be downloaded here.

Note: this is an unsupported product.


TRS-80 Colour Computer 3 Emulator (released to freeware)

Download version 1.6B of the CoCo 3 Emulator

Download MS-DOS file enhancements and extended error messages for CoCo 3 BASIC (see readme.txt within)

Download the older version 1.3 release of RETRIEVE and DSKINI

Source code for CoCo 3 Emulator Version 1.6B plus the beta Version 1.7

  My TRS-80 CoCo 3 Emulator was in distribution as shareware from 1994 to the end of 2001. (From 1997 to 2001, the CoCo 3 Emulator was distributed by Rick's Computer Enterprises.) The emulator was designed to work with MS-DOS, and will still work with most versions of Windows which support an MS-DOS Mode. It does also work within Windows, but would run slowly. As newer versions of Windows such as XP and 2000 no longer support MS-DOS Mode, support for the emulator is becoming more difficult. So, I've decided to discontinue the CoCo 3 Emulator as a shareware product, and instead make this Version 1.6B available as freeware, as well as its source code. (The emulator was written in 16-bit Intel assembly language.) It's my hope that by making the source accessible, it will help speed along development of the newer generation of emulators which work with operating systems mine does not (e.g. Windows XP, Mac OS X, etc.), thereby keeping to CoCo alive.

Generally speaking, this emulator was fairly robust with CoCo BASIC and OS-9 as well as many machine language programs for the CoCo 3. It did, however, suffer great performance problems with games that made aggressive use of the CoCo 3's custom GIME graphics chip's more advanced features (including page flipping and mid-screen mode changes). For OS-9 users, a custom-designed boot ROM file was included so that one could boot OS-9 without the need to transfer the CoCo's ROM to your PC. It also included a virtual hard drive and real time clock drivers for OS-9.

Optimal system requirements for the CoCo 3 Emulator are VGA compatibility, 429K of low DOS memory free and 384K of free EMS. (Use the MS-DOS "MEM" command to check your available memory.) A SoundBlaster on port 220H is also needed for SoundBlaster-based sound. With an additional 1.5MB of EMS memory, you can run the emulator as a 2MB CoCo 3. (To use the 2MB mode requires OS-9 and special 3rd party drivers that were sold separately from OS-9. If you are not familiar with the 2MB OS-9 setup, do not enable the 2MB mode in the emulator. OS-9 will not work on a 2MB CoCo without the appropriate drivers.) If EMS is unavailable, the emulator will work as a 128K CoCo 3.

I'd like to thank those that registered the CoCo 3 Emulator with me over the years, and a particular thanks to Rick Cooper of Rick's Computer Enterprises and his friends at CFDM for providing the push that made this product possible. Please note that the original Version 1.60 will remain an exclusive to registered users. Version 1.6B is a slightly different version. It has a different -- but compatible -- 6809 core, as the original cannot be distributed publicly for copyright reasons. As such, Version 1.6B runs somewhat slower, though it should still be plenty fast on modern platforms.

IMPORTANT: There are some compatibility issues between the CoCo 3 Emulator and programs that make more ambitious use of the graphics hardware, among other things. See the COCO3.DOC file within Version 1.6B under the sections "7.1 TROUBLESHOOTING" and "9. COMMENTS" for more details.

Also available:

  • A patch to the CoCo 3's BASIC ROM which, when used in conjunction with this CoCo 3 Emulator, will give more descriptive error messages (e.g. "?SYNTAX ERROR" instead of "?SN") and also an array of commands which allow you to load/save files directly to your MS-DOS directory from within the emulator. Warning: this patch uses special features which are only compatible with my CoCo 3 Emulator. The ROM generated by the patch cannot be used with other emulators.
  • Older version 1.3 releases of RETRIEVE and DSKINI for those having trouble with the ones that are in the version 1.60 package.
  • An incomplete Version 1.7 is included in the source code download. This version was an experimental which provided new functionality beyond the CoCo 3, such as 640x480 16-colour and 320x200 256-colour video modes, support for the full PC keyboard, and 16MB of RAM. Version 1.7 was a beta version, so it may contain unknown bugs or problems.
  • The technical specifications for the .DSK virtual disk format can be found off-site here. Note that my CoCo 3 Emulator version 1.6B only recognised the first of the optional header bytes, which allowed the user to specify a sectors/track count of other than 18.
  • To transfer files between your PC and OS-9 virtual disks, I recommend the third-party os9.exe by Carey Bloodworth. Source code is included. (Unfortunately, I don't have any contact information for Carey. If you have questions about this program, I suggest trying the newsgroup bit.listserv.coco.)

It's been noted on bit.listserv.coco that RETRIEVE and DSKINI may not work with 360K 5 1/4" drives unless you set your PC's BIOS to (mis-)identify the drive as a 720K 3 1/2" drive instead. If you are having difficulty with both versions of RETRIEVE/DSKINI, this is another option to try. Consult your PC's motherboard manual for details on BIOS configuration.

Note: this is an unsupported product.


Timex/Sinclair 1000 Emulator (Java)

Go directly to the Timex/Sinclair 1000 Emulator now

Browse the Software Library of ready-to-run programs for the T/S 1000 emulator

Download my older T/S 1000 Emulator for MS-DOS

  If you're browser supports Java and JavaScript, you'll be able to run a Timex/Sinclair 1000 in your browser window right now. This is a follow-up to my previous Level I BASIC in a browser.

OK, I know the Timex/Sinclair 1000 is not a TRS-80, but there is a connection. Having done a Z-80-based emulator already with my TRS-80 Model I Emulator, and owning a Timex/Sinclair 1000, I decided to see if I could reverse engineer it as well. So, it uses the same core as my TRS-80 Emulators, and, being my only home computer emulator that isn't TRS-80, wasn't big enough to warrant a page of its own.

This emulator emulates a Timex/Sinclair 1000 with TS1016 16K RAM Expansion Pack.

With a little work, this browser-based emulator can also use the same cassette images used by other emulators. For details, see the import/export section of saving your program on the help page.

If you are running MS-DOS or Windows, you can also download my older MS-DOS-based T/S 1000 emulator if you prefer.


General Emulator History

Follow this link to read a recount of my introduction to the world of computers through the TRS-80, the inspiration that lead me to start writing emulators, and the impact it has had.


About ROMs

In short, don't email me asking for ROMs. Forget it. I do not endorse piracy in any form, including the concept of orphanware. Please don't email me trying to persuade me that my point of view needn't be so harsh; it hasn't changed in ten years of emulation and uncountable debates.

The emulators were designed for people who already used the computers, and want to continue to use them after maintaining the physical hardware is no longer practical. The emulators come with instructions on how to transfer the ROM image from a legitimately-working original TRS-80. If your TRS-80 is not working I cannot help you. In that situation, you won't be able to read your software or data either.

The good news is that the Model III/4 Emulator running a Model 4 DOS such as LS-DOS or TRSDOS version 6.x or the CoCo 3 Emulator running OS-9 Level II do not need the original ROMs in order to function. I have written a small stub boot ROM which will load these particular operating systems, which otherwise only rely on the computer's ROM to boot. So if you have PC-readable TRS-80 disks but not a functional TRS-80, there is still hope.

The Timex/Sinclair 1000 Emulator, mercifully, is an exception, as the ROM for that particular system has been released into the public domain and so can be distributed with the emulator.

The TRS-80 Level I Simulator is not an emulator and so does not contain a ROM.



These are some links which TRS-80 enthusiasts might like to check out:

All content 2000 Jeff Vavasour. Updated November 04, 2009.