[syslinux] syslinux-3.36 Physical Floppy Disk Access Problem

[H. Peter Anvin]

Desmond Boyd wrote:
> As requested, I have tested the distributions listed below to try to isolate 
> when physical disk drive access for me was lost, results are as follows:
> 
> Physical Disk Drive B: OK with Virtual Disk Drive as A:
> 3.20
> 3.30
> 3.31
> 3.32 Pre1
> 
> Physical Disk Drive B: Not Present only Virtual Disks A: and B:
> 3.35
> 3.35 Pre1
> 3.35 Pre2
> 3.35 Pre3
> 3.35 Pre4
> 3.35 Pre5
> 3.36
> 3.50
> 

Could you also test the various 3.32-preX releases (2 to 8) to narrow
down the failure further?

The most likely failure seems to be between 3.32-pre3 and -pre4:

    memdisk: Constrain input drive numbers both by equipment byte and
    INT 13h

    Apparently on some BIOSes, INT 13h return a bogus number of floppy
    drives when the real value is zero (probably because the code
    doesn't check the validity bit in the equipment byte.)  Do it
    ourselves if we need to.

There should be a line when MEMDISK boots up saying something about "INT
13 08", what is that printout?

	-hpa