thorr wrote: ↑Sun Apr 28, 2024 1:37 amI say keep it simple for starters and get it working with the AppleWin HDD card. If this is the equivalent of a smartport, it should be possible to connect four HDD's at the same time like the FloppyEmu can. Details can be found on page 10 and 11 here: https://www.bigmessowires.com/femu-instructions.pdf SCSI could come later if there is demand for it.
That's a cool hack, but I think it depends on using the actual SmartPort firmware and protocol (and would also be limited to a floppy drive data rate?). The AppleWin HDD is a very simple device that just supports the ProDOS firmware calls.
thorr wrote: ↑Sun Apr 28, 2024 1:37 amDefinitely max out the RAM. Accelerator would be nice eventually, but not needed for round 1 in my opinion.
There isn't really one agreed-upon "max", so RAM size might need to be an option for compatibility reasons. 4 MB was the official limit for RAM expansion size, while 8 MB became possible with later RAM chips (i.e. the vast majority of IIgs software probably never encountered this much RAM during its support lifetime). More than that seems to require patching GS/OS and decoding banks 80-DF as RAM (as far as I know, not readily possible without an accelerator on an actual IIgs).
thorr wrote: ↑Sun Apr 28, 2024 1:37 amSerial support would be nice (with a USB to serial adapter). I have an Imagewriter II printer I would love to use with it and also would like to write some programs to take advantage of it.
The serial port is a Zilog SCC (Z8530), which I think needs to be written. The only existing core I know of that would need this chip is MacPlus, and it doesn't seem to be there.
thorr wrote: ↑Sun Apr 28, 2024 1:37 amIt would be cool to have Composite emulation mode and RGB mode.
Do you mean something like the "Composite Blend" option in the MegaDrive core? The composite output on IIgs is just RGB put through an off-the-shelf encoder chip.
thorr wrote: ↑Sun Apr 28, 2024 1:37 amIt would also be nice to have dual Mockingboard support (and in the IIe core). As far as I know the IIgs can play Apple II games faster so it would be nice to have the option to play them that way with better sound when it is available.
The issue with stuff like this is that it makes the core bigger for very little benefit. Maybe a Mockingboard is tiny, though (it's been a while since I've looked at the AY, but I want to say it's basically three counters in a trenchcoat)? This would probably also wind up needing an implementation of the "Slotmaker" chip, which controls the mapping of internal vs. expansion slot ("Your Card") hardware.
thorr wrote: ↑Sun Apr 28, 2024 1:37 amI am looking forward to hard drive images filled with Apple IIgs games (assuming that is possible). Many games probably require floppies.
I'm not super-familiar with IIgs software, but I think most games are designed to be booted. If they use a standard ProDOS loader (either originally or because they were cracked) they might not care too specifically about the disk format and perhaps could be mapped to a RAM disk or similar. I don't know what it would take to build something like WHDLoad for GS/OS, or if anyone's attempted/done that.