2. I can send you made by me using Dan Potter's KOS? Anyway, when I use a .elf, it doesn't show anything (but I know it's emulating - framerate and lxdream console messages). When I build an image file, it works normally.
If you can email it to me, that would be helpful (esp w/ source if possible).
3. I didn't know these calling ways, thank you. But even so, GUI menu says it's mounted, but my code doesn't work, except when I build a cd...
Ok that's odd. The disc image and disc are identical? You can't boot the disc image either?
I should note that there are some subtle differences between booting a disc image and running an elf binary directly - the latter skips the BIOS boot sequence entirely, although it will still run the IP.BIN bootstrap if you have one installed. In other words, if your program depends on the BIOS setting something up for you, it may or may not work correctly. If your program makes BIOS syscalls though, it _definitely_ won't work atm without the going through the full boot.
 There's some initial work in progress towards implementing the known BIOS syscalls for precisely this reason (see src/bios.c), but I've never finished it as I don't use them myself.