by Bret » Thu Apr 15, 2010 7:50 am
If AH is 0 on return, that is indeed a bug. It should be 1. I will look into that and fix it in the next version.
CL = 1 is correct. The driver only provides a very basic set of extended INT 13h functions. It does not support removable disk functions (bit 1 of CL), since USB disks almost never correctly support removable media functions, even when they have removable media. The driver also does not support EDD functions (bit 2 of CL), since the main purpose of EDD is to provide the real physical parameters of the disk ("real" CHS values, DMA info, etc.) that don't apply to USB disks.