[SOLVED] Read Tape Contents

JJJCR · 05-11-2012, 04:22 AM

hi gurus, is there a general command to read the contents of a tape.

let's say an old tape lying around on the server room, and you don't know whether tar or cpio or other commands was used to write files on the tape.

is there such a general command to list the contents of a tape?

thank you for any input.

michaelk · 05-11-2012, 06:54 AM

Not that I know of. I would use the dd command to dump some data from the tape. By examining the header if one exists you might be able to determine the application or command that created the backup.

Satyaveer Arya · 05-11-2012, 10:58 AM

I assume that you're askin about DAT tape drives. Suppose your tapes are loaded on /dev/st0.
Before reading the tape's data first you have to rewind the tape.

Code:

# mt -f /dev/st0 rewind

Then to list the contents of tape-

Code:

# tar -tzf /dev/st0

Or for more information you can check here.

JJJCR · 05-21-2012, 02:43 AM

Quote:

Originally Posted by michaelk

Not that I know of. I would use the dd command to dump some data from the tape. By examining the header if one exists you might be able to determine the application or command that created the backup.

hi michael, what you mean by examining the header? how do i read the headers?

thank you.

JJJCR · 05-21-2012, 02:46 AM

Quote:

Originally Posted by Satyaveer Arya

I assume that you're askin about DAT tape drives. Suppose your tapes are loaded on /dev/st0.
Before reading the tape's data first you have to rewind the tape.

Code:

# mt -f /dev/st0 rewind

Then to list the contents of tape-

Code:

# tar -tzf /dev/st0

Or for more information you can check here.

Hi Arya, it's LTO 2 tape drive, so basically if there's no general command. then the best way is just to overwrite the contents of the tape. or try the luck of using tar, cpio and other commands to determine what command was used to dump the data to the tape.

Satyaveer Arya · 05-21-2012, 04:27 AM

I don't know exactly how to use or read the contents of LTO 2 tape drive. But in our data centre my colleague use windows application software to access that and you can refer this document here. I hope it will help you somehow.

pan64 · 05-21-2012, 04:42 AM

Quote:

Originally Posted by JJJCR

hi michael, what you mean by examining the header? how do i read the headers?

thank you.

If you could read the content, so you can have files you can identify the types by reading the first few bytes. The command file can do it and can give you an answer. But first you need to read the tape. With dd you can copy the content to disk and you will get much quicker access to the content.

michaelk · 05-21-2012, 06:24 AM

The file command might work or you could use a hex editor like hexedit to examine the data.

JJJCR · 05-27-2012, 05:11 AM

thank you guys

JJJCR · 05-27-2012, 05:13 AM

Very good and useful suggestions, thanks for all your help