dd command to test tape drive

[Coolmar]

Hi folks,
I am having some I/O errors in data protector during backups. I wanted to do a 'dd' to the tape drive to see if it works ok, but I can't run the dd command. The output is posted below. Also, if it works ok on the server that the drive is attached to, I wanted to test from a remote system. Is that possible with dd?

# mt -f /dev/rmt/0mn status
Drive: QUANTUM SuperDLT1
Format:
Status: [0]
File: 0
Block: 0

# dd if=/dev/rmt/0mn of=/dev/null bs=1024k
/dev/rmt/0mn: No such device or address
dd: cannot open /dev/rmt/0mn

[Mel Burslan]

using the device driver without the "n" at the end, may help. The "n" suffix at the end means to mount it with no-rewind and it may b giving you grief

dd if=/dev/rmt/0m of=/dev/null bs=1024k

[Coolmar]

I tried that one as well and got the same error.

[Mel Burslan]

I am perplexed but did you try mounting the tape without the "n" option, i.e., letting it rewind to the beginning, prior to running the dd command ?

[A. Clay Stephenson · Accepted solution]

First of all, the mt status command displays
Status: [0]
when there is no tape loaded in the drive or at least it thinks there is no tape in the drive so until you get the Status line to display more than simply "[0]", you aren't going to get dd or anything else to work.

[Coolmar]

Thanks Clay....guess it helps to have a tape in there! You'd think it was Monday morning ;0)