tape drive problem

[Bill Campbell]

On Sat, May 31, 2008, Vu Pham wrote:
>
>
>Vu Pham wrote:
>>My tape drive suddenly reports the following error when I write to it.
>>
>>tar: /dev/st0: Cannot open: Read-only file system
>>
>>What can cause this ? I used a tape cleaner tape to clean it but it does 
>>not fix. And the "dirty" LED is not on.
>>
>>It is a DLT1 tape drive.
>>
>
>More :
>
>[root at pepper3 log]# mt -f /dev/st0 status
>SCSI 2 tape drive:
>File number=0, block number=0, partition=0.
>Tape block size 0 bytes. Density code 0x1a (DLT 20GB).
>Soft error count since last status=0
>General status bits on (45010000):
> BOT WR_PROT ONLINE IM_REP_EN
>
>It says "WR_PROT". That's why tar cannot write to it. But why ? Hardware 
>problem ?

My guess is that you have engaged the tape's write-protect.

Most mag tapes have some method to write-protect them, the method
depending on the type of tape.  It's been a while since I looked
a tapes, but as I remember the DDR DAT style tapes have a little
slide at the back of the cartridge.  The 1/4in tapes such as the
DC600s have a rotating mechanism on the front side (towards the
heads), etc.

Bill
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