IPS_BLKSIZE
length = (length + IPS_BLKSIZE - 1)/IPS_BLKSIZE;
dsc->ipsd_disk->d_sectorsize = IPS_BLKSIZE;
dsc->ipsd_disk->d_mediasize = (off_t)totalsectors * IPS_BLKSIZE;
command_struct->lba = off / IPS_BLKSIZE;
length = (length + IPS_BLKSIZE - 1) / IPS_BLKSIZE;