DOSBox-X emulation fixes:
- Accurate PS/2 keyboard emulation, support for scan code sets 1, 2, and 3, emulation and response to LED commands, reset commands, mode changes, and obscure commands
- Gravis Ultrasound panning register fixes. Mainline DOSBox seems to have a buggy implementation that ends up locking all audio to center no matter what value is written. I fixed that code in this version. DOS programs that rely on stereo sound should actually play in stereo now through DOSBox.
- PS/2 AUX port emulation. This enables DOS programs and OSes to work that don't use INT 33h and communicate directly with the PS/2 mouse connected to the keyboard controllers "AUX" port. This code is wired in so that INT 33h emulation is enabled by default, but shut down the instant the "reset" command is sent to AUX.
- CGA snow emulation. If you set machine=cga and enable the option, video memory I/O is slowed down to CGA speeds and writes will trigger "snow", just like an actual CGA.
- Sound Blaster "Goldplay" support. Back in the early 1990's a tracker library was used in some demos that provided music playback to LPT DAC and various other outputs including Sound Blaster. The problem is the library's Sound Blaster support uses a weird hacked DMA transfer mode that is basically setting the DMA buffer length to 1 byte and having the controller loop over that, then writing the byte from an interrupt handler. Mainline DOSBox tends to render this as a low frequency "rumble", while this fixed version detects that case and plays the audio perfectly. This fix is ideal for some demoscene entries in the 1991-1993 time frame.
DOSBox-X emulation additions:
- ISA Plug & Play emulation. This is useful for PnP-aware DOS programs or for running Windows 95 within DOSBox. The implementation provides both BIOS and I/O compatible PnP interfaces to the PnP-aware software.
- Serial mouse emulation. You can enter "serial1=serialmouse" into your dosbox.conf to have DOSBox emulate a Microsoft compatible mouse connected to your serial port of choice. Some software made prior to the introduction of PS/2 mice need this. With Windows 1.0, this option is the only way to get a usable mouse cursor within the graphical interface.
- Higher memory limit. Mainline DOSBox limits system memory to no more than 64MB. This branch removes that limit and allows up to 512MB.
- Finer-grained memory sizes. If you want to relive the days when PCs had less than 640KB of RAM or had odd extended memory sizes like 1630KB, you can use the memsizekb= option to specify memory size in KB instead of MB.
- Refresh rate control. You can set a fixed refresh rate that all video modes are locked to. For example if you are capturing content for television, you can force the refresh rate to 59.94 to avoid framerate conversion issues with your video editing software later.