Fun with AHDI.

[shenson@nyx.cs.du.edu (Stephen Henson)]

Right I'm downright bloody furious now ...
        AHDI 6.06 and previous do something rather clever. I've been trying
to persuade AHDI to get GEMDOS to ignore a partition whilst still allowing
Minixfs to recognise it (so TOS without MiNT/Minixfs wont write all over
the bloody thing). As I said a while back, 512 byte sectors are no problem
at all I can squeeze a pseudo tiny TOS partition in there which GEMDOS will
never touch (because the root directory is full). With anything else the
best I can do is to confuse GEMDOS by making certain boot sector parameters
zero.
        AHDI notices the zero parameters and feeds back a zero from Getbpb.
This certainly keeps GEMDOS quiet. *However* Rwabs's fail on this drive
because it isn't logged in through Getbpb!! It also reads as forever changed
because you clear the disk change flag with Getbpb!!
        OK I think, lets bypass the partition operations and use the physical
mode operations with the PUN_INFO structure. Guess what, the PUN_INFO
structure isn't filled in until the drive is logged in with Getbpb. What's
even worse is that it signals the drive as perfectly valid with the PUN_INFO
structure but starting at sector zero (i.e. lets trash the root sector shall
we ???).
        Ever get the feeling you're pissing into the wind ?
        Right that gives me one last option. Make the BPB look like the root
directory is off the end of the partition. Hopefully when GEMDOS tries to look
at the root directory it'll screw up with some error or other.
        If that doesn't work I'll start throwing heavy objects onto the AHDI
disk and give up.

Steve.
P.S. who's paying me to do this ? :-)