Fix a bug in MAPDRV and a bug in the MFRSD kernel regarding DEV_STATUS routine - Githubissues

Konamiman / Nextor

A disk operating system for MSX computers, forked from MSX-DOS 2.31

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Fix a bug in MAPDRV and a bug in the MFRSD kernel regarding DEV_STATUS routine #119

Closed Konamiman closed 9 months ago

Konamiman commented 1 year ago

The MAPDRV function call code was corrupting the register holding the drive number while unmapping all the drives assigned to the device in the case where the driver reports that the device has changed. Thus the mapping information ended up written to an incorrect memory area.
The MegaFlashROM SCC+ SD driver was reporting "device changed" even after the device had been accessed with DEV_RW. A device is no longer considered as "changed" after it has been accessed.

Scenario to reproduce the issue:

MFRSD with two cards, the second one has at least 2 partitions.
On boot, A: is card 1 partition 1, B: is card 2 partition 1.
Right after boot map any drive to card 2 partition 2: MAPDDRV d: 2 3 1-3
Now switch to drive D:, computer crashes.

Steveneska commented 1 year ago

I don't know if it's related to the same issue but running a MFRSCC+ SD with 2 SD Cards in the same configuration (A: is SD Card 1 partition 1 and B: is SD Card 2 partition 1), mapping C: and D: to SD Card 2 partitions 2 and 3 respectively and then switching to drive B: will return a bad drive name error in Basic and switching to C: right after a failure to switch to B: will hand the computer.

Somehow though, running let's say DEVINFO from drive A: before switching to drive B: will not reproduce this behavior as the partitions and drives are recognized as expected.