19H query DOS default disk 0eH select DOS default disk 47H query current default directory 3bH set default directory 2fH query DTA (Disk Transfer Addr) 1aH set DTA 54H query disk verify status 2eH set disk verify status 36H get total and free disk space 32H get DPB disk info 1bH 1cH get disk info ◄superseded► 3305H query ID of boot drive 0dH reset disk (flush buffers) DS IOCTL 'F' flush DoubleSpace cache DS IOCTL 'I' invalidate Dblspace cache INT 13H BIOS Disk services INT 24H critical error handler address INT 25H/26H DOS direct disk read/write DoubleSpace API (see if disk is compressed, swap IDs, real free space,etc.) ────────────────────────────────────────────█▌Block device IOCTL functions▐█ 440dH 60H get device parameters 440dH 40H set device parameters 440dH 61H read track 440dH 41H write track 440dH 62H verify track 440dH 42H format and verify track 440dH 66H query media ID 440dH 46H set media ID 440dH 68H sense media type 4408H removable media query 440eH get logical drive 440fH set logical drive 4411H query IOCTL device ────────────────────────────────────────────────────────────────────────────── INT 13H BIOS disk I/O Service Groups DOS Functions