TAPE DRIVES

rmt0.x where x = A + B + C

A = density        0 = high      4 = low
B = retension      0 = no        2 = yes
C = rewind         0 = yes       1 = no

tctl -f (tape device) fsf (No)        Skips forward (No) tape markers
tctl -f (tape device) bsf (No)        Skips back (No) tape markers
tctl -f (tape device) rewind          Rewind the tape
tctl -f (tape device) offline         Eject the tape
tctl -f (tape device) status          Show status of tape drive

chdev -l rmt0 -a block_size=512        changes block size to 512 bytes
                                       (4mm = 1024, 8mm = variable but 
                                        1024 recommended)
dd if=/dev/rmt0 bs=128k count=1 | wc -c
Displays the block size of an unknow tape. Set block size to 0 first.

bootinfo -e             answer of 1 = machine can boot from a tape drive
                        answer of 0 = machine CANNOT boot from tape drive

diag -c -d (tape device)        Hardware reset a tape drive.
diag -c -d rmt0

tapechk (No of files)           Checks Number of files on tape.

< /dev/rmt0                     Rewinds the tape !!!