H89 Emulators
I've worked on several different emulators, originally starting out with my own, written in C++ - Virtual H89. I've also written one in JavaScript and you can run it directly on my jsH89 page. Both of these have a very small user base, so I have started working on H89 Emulation in MAME.
Virtual H89 Status
This emulator is fairly complete. It supports both Heath's H-88-1 hard-sectored controller and Z-89-37 soft-sectored controller. Several MMS boards are also supported, including their 128k RAM upgrade board, soft-sectored controller with both 8" and 5.25" drive support, and their SASI controller. It currently runs on Mac OS and Linux. Since this uses a very old framework (OpenGL and GLUT), in order to make it more user friendly, it needs to be moved to a more current framework. Since MAME already has wide support and a huge user base, I'm going to be focused on improving the H89, H19, and other Heathkit systems in MAME. If anyone is interested in helping me improving this emulator, let me know, I would definitely devote time it.
jsH89 Status
This emulator run well in the browser, I had recently updated it on my site and was working on implementing the Z-89-47 interface card and related H/Z-47 8" Drive System. Unfortunately, the system I was using to write the code crashed, and at some point it had stopped doing automatic disk backups, so all the latest work is lost. I may get back to it, but for now, I'm focused on MAME development (see next section). If anyone is interested in helping with this emulator, let me know and I will devote time to it.
MAME H89 Status
MAME originally started as an arcade machine emulator. A sister project called MESS was started to emulate personal computers and had a skeleton H89 system. Several years ago the two projects merge and took the MAME name.
In 2017, I did some work to improve the H19 and H89 emulation under MAME, but took some time off before starting back just this year (2023), to continue improving the systems. As of the MAME 0.256 release, the H89 now has enough functionality to be classified as a "working" system. I implemented the Z-89-37 soft-sectored floppy disk controller, which allows the system to boot both HDOS and CP/M system disks. Since the complete H19 terminal functionality is shared with the H89 emulation, fast-action graphic games can even be played. The Cassette Interface board has also been implemented for the H88 clone, and both WAV and H8T files can be loaded from cassette.
The biggest thing still missing is support for the hard-sectored disk controller. Since MAME itself is lacking support for hard-sectored disks, that needs to be added before H89 support is possible. There was a PR for hard-sectored support, but that had to be reverted due to regressions for some of the soft-sectored systems. Although those issues were address, the mame developers still has not merged the updated PR, although I have some concerns about how that was implemented. I plan to continue improving the H89 emulation in MAME to support additional disk controllers, add-ons, etc. The H19 implementation is mostly complete. The main thing lacking is support for interlace mode that some of the third-party ROMs and the GP-19 graphics board supported/required. This is causing the GP-19 132x50 text mode to not work. Since interlace mode is not supported well in MAME, that needs to be addressed before the H19 can properly support it.
