DATASTART
/ (drive.label.drive_size - (DATASTART * DEV_BSIZE))));
drive->sectors_available = drive->label.drive_size / DEV_BSIZE - DATASTART;
drive->freelist[0].offset = DATASTART; /* starts here */
drive->freelist[0].sectors = (drive->label.drive_size >> DEV_BSHIFT) - DATASTART; /* and it's this long */