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.

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.