LinuxQuestions.org
Latest LQ Deal: Latest LQ Deals
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - General
User Name
Password
Linux - General This Linux forum is for general Linux questions and discussion.
If it is Linux Related and doesn't seem to fit in any other forum then this is the place.

Notices


Reply
  Search this Thread
Old 05-02-2005, 05:50 PM   #1
jahearne
LQ Newbie
 
Registered: Aug 2004
Location: San Francisco
Distribution: Fedora, SuSe & Ubuntu
Posts: 5

Rep: Reputation: 0
Using dd to get an image of a DLT tape


Anybody have any suggestions using dd to extract an image copy off of a DLT VS160 tape? The problem is that a large backup was overwritten with 4 megs of data. By normal means, the previous backup is gone. The tape drive is properly configured in SUSE 9.2 - details below. The 4 meg backup is 4065280 bytes in size. I have to use a block size of 65536 or larger (bs=64k) otherwise get "cannot allocate memory" error. So far I can only get the backup header off the tape. Some examples I've used so far are:
dd if=/dev/st0 of=/media/tape.dd bs=64k
dd if=/dev/st0 of=/media/tape.dd bs=1024k
dd ibs=1024k conv=noerror,block if=/dev/st0 of=/media/tape.dd
dd if=/dev/st0 bs=4065280 skip=1 | dd bs=1024k | dd of=/media/tape.dd seek=1

and various others using different block sizes etc.

Tape drive info:
st: Version 20040403, fixed bufsize 32768, s/g segs 256
(scsi2:A:5): 160.000MB/s transfers (80.000MHz DT, offset 96, 16bit)
Vendor: QUANTUM Model: DLT VS160 Rev: 2500
Type: Sequential-Access ANSI SCSI revision: 02
Attached scsi tape st0 at scsi2, channel 0, id 5, lun 0
st0: try direct i/o: yes (alignment 512 B), max page reachable by HBA 1048575
Attached scsi generic sg0 at scsi2, channel 0, id 5, lun 0, type 1

mt -f /dev/st0 status
drive type = Generic SCSI-2 tape
drive status = 1342177280
sense key error = 0
residue count = 0
file number = 0
block number = 0
Tape block size 0 bytes. Density code 0x50 (unknown).
Soft error count since last status=0
General status bits on (45010000):
BOT WR_PROT ONLINE IM_REP_EN

Any suggestions would be great!
Thanks
John
 
Old 05-02-2005, 07:28 PM   #2
michaelk
Moderator
 
Registered: Aug 2002
Posts: 19,398

Rep: Reputation: 3089Reputation: 3089Reputation: 3089Reputation: 3089Reputation: 3089Reputation: 3089Reputation: 3089Reputation: 3089Reputation: 3089Reputation: 3089Reputation: 3089
Have you tried:
dd if=/dev/st0 of=/media/tape.dd bs=64k count=64
 
Old 05-02-2005, 07:46 PM   #3
jahearne
LQ Newbie
 
Registered: Aug 2004
Location: San Francisco
Distribution: Fedora, SuSe & Ubuntu
Posts: 5

Original Poster
Rep: Reputation: 0
Thanks, I just did and got the same results. I'm begining to think it's just a limitation of dd; it reaches the eof mark on the first record, which is the job header of the backup tape and quits. That's why I can't get past the first filemark. There's gotta be a way to get that data that's lying beyond the 4 meg worth of overwritten info.

Thanks for replying,
Jahearne
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
Debian won't see a DLT Tape Library evank Debian 6 10-14-2005 06:34 PM
DLT Tape Library synpse Linux - Hardware 1 02-22-2005 01:34 PM
DLT Tape dvong3 Linux - Hardware 3 05-14-2004 04:46 AM
SCSI, DAT and DLT tape jimmy2002 Linux - Hardware 4 04-20-2004 08:02 AM
DLT 40 How do I access this tape drive? chr15t0 Linux - Hardware 1 02-14-2003 11:13 AM

LinuxQuestions.org > Forums > Linux Forums > Linux - General

All times are GMT -5. The time now is 07:35 AM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration