] By the way, why is MEGA-SCSI more fit for floppy emulation than the
] other interfaces??? (a technical explanation please).
In MEGA-SCSI, the 'disk rom' is not stored in a ROM but in a battery-powered
SRAM that can easily be reprogrammed entirely.
The floppy emulation program for MEGA-SCSI makes use of this feature. When
you start a .dsk game, the 'disk rom' in the SRAM is patched and the machine
is rebooted. After reboot, the patched 'disk rom' will consider the disk
image as drive A: and start the MSX as such. So, at that moment, all other
drives will not be visible anymore and the emulation is done at the lowest
level possible.
Furthermore, the floppy emulation patch removes itself from the SRAM (and
restore the SRAM to normal operation) if you boot the MSX with a certain
key-combinationed pressed.
I think that it should be possible to write a similar floppy emulation
program for the Sunrise IDE interface, since this interface also stores the
'disk rom' in re-programmable memory. If I'm informed correct, the diskrom is
stored in a FLASHROM. And these can be re-programmed. But I do not know how
easy this is and how many times they can be re-programmed.
Kind regards,
Alex Wulms
--
Visit The MSX Plaza (http://www.inter.nl.net/users/A.P.Wulms) for info on
XelaSoft, Merlasoft, Quadrivium, SD-Snatcher on fMSX, the MSX Hardware list,
XSA Disk images, documentation, Japanese MSX news from Ikeda and lots more.
--
For info, see http://www.stack.nl/~wynke/MSX/listinfo.html
