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Reading HP 9000 DLT backup tape under Windows 2000

 
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Jean-Yves Rouffiac
Occasional Advisor

Reading HP 9000 DLT backup tape under Windows 2000

Hello,

I have been asked by a client to see whether it is possible to read data from old backup tapes written on an HP 9000 (which they no longer have), and export the data into some flat files under Windows.

I have no experience of the HP 9000, nor do I yet know what backup-program was used to write to the tapes - nothing quite like working without any information ;)

We do however have a DLT drive on one of our Win2000 boxes.

The tapes are Maxell DLTtape IV, but there is no indication as to their capacity.

Can anyone provide me with any pointers as to how to proceed. For example, is there a backup program that is provided as standard on the 9000? (I have seen OmniBack mentioned, but am not clear as to whether this is the correct application), is there a version available for Windows, etc, etc.

Any help would be very gratefully received.
12 REPLIES 12
Vincent Farrugia
Honored Contributor

Re: Reading HP 9000 DLT backup tape under Windows 2000

Hello,

The success of this depends on with which application/program did they write the old backups. For instance, if they wrote them in tar format, it's different to fbackup, and it's different to Omniback.

So first question you need to ask them is, with which application/backup program did you write these old tapes?

HTH,
Vince
Tape Drives RULE!!!
Jean-Yves Rouffiac
Occasional Advisor

Re: Reading HP 9000 DLT backup tape under Windows 2000

Hi Vince,

Thanks very much for the reply - I have asked the client for info on the backup program but as yet have had no reply (it's quite possible that they don't actually know).

Would it be possible to find this out from the Win2000 end? ie is there some software that will read the contents and give an idea of what filetype it is (maybe it would have a .tar file extension for example?).

I'm thinking along the lines of an Installable File System that could be started under Win2000 to read the HP 9000 format.

Thanks.
Vladimir Vybiral
Valued Contributor
Solution

Re: Reading HP 9000 DLT backup tape under Windows 2000

This reading from w2k end seems impossible to me, as the tape is formatted by the application that has been used for backup and the format differs app to app. The only possibility is really ask the customer again which application has been used for writing the tape. Or, find an UX box and a pro that would be able to mount the tape and read the contents somehow. This could be done on UNIX, but sorry, nothing like that on Win as far as I know.
When speaking, Your words should sound better than Your silence - Arabic proverb
Vincent Fleming
Honored Contributor

Re: Reading HP 9000 DLT backup tape under Windows 2000

ANY unix-type box would do for reading the tape - there's so much more you can do with UNIX that you just can't do in windows.

Here's what I suggest if you haven't a unix-type box around - find a PC that they are not using, and a SCSI card, and borrow a DLT drive from one of their systems.

Then load FreeBSD or Linux on it (download for free). Poof! Instant unix-box. [hint: get the boot floppy, then you can load the O/S directly off their FTP servers.]

You can then use the 'dd' utility to pull the data off the tape. Then use the 'file' utility to find out what format it is.

# dd if=/dev/rmt/0m bs=32k of=/tmp/backup.file
# file /tmp/backup.file

It's very likely that you could unpack it on the UNIX box also, then ftp (or whatever) the data off to Windows.

Good luck,

Vince
No matter where you go, there you are.
Jean-Yves Rouffiac
Occasional Advisor

Re: Reading HP 9000 DLT backup tape under Windows 2000

Thanks guys, that's really helped. The good news is that I have found a colleague in another office who has a unix box with DLT tape drive, so I shall pass it on to him with the information that you have provided, and hopefully he'll be able to extract the data for me.

Again, thank-you :-)



James Perry
Advisor

Re: Reading HP 9000 DLT backup tape under Windows 2000

I have had to do a similar operation based on a case of tapes we had offsite, but it was not know which OS was used or what, if any, backup software was used. What I found helpful was to do a 'dd if= bs=1K | more' For most backups, I found the following file header/basic data formats. The file I am using for illustration is called test. If has a single line of "line 1"

CPIO:
0707070000010000021006660000000000030000010000000763612356400000500000000007testLine 1
0707070000010000021006660000000000030000010000000763612356400001300000000000TRAILER!!!0707070000010000021006660000000000030000010000000763612356400000500000000007testLine 1
0707070000010000021006660000000000030000010000000763612356400001300000000000TRAILER!!!0707070000010000021006660000000000030000010000000763612356400000500000000007testLine 1
070707000001000002100666000000000003000001000000076361235640000130000000001 blocks

Tar:
test000066600000000000003000000000070763612356400116310ustar00rootsys00000000000000Line 1

Fbackup:
ANSII standard label not yet implemented19456 1 /tmp
96 1 /tmp/test
7 1 /tmp/test/test
BOHBOTrpcbind.fileoutut9755.outBOHBOTLine 1

As for OmniBack, I am not familiar with it's backup format. What I do know is that most backup software uses Tar or CPIO as their basic backup internals. I know that this is the case for Veritas NetBackup and EMC's EDM software.

With respect to Veritas NetBackup (the software we use) there tape has the format that there is a tape header containing the barcode label as the first file and then each subsequent backup are placed as additional files.

The standard header (first file) looks something like this:
VOL1SU0391^A^F>^O^PM-3 ^A^DThIs Is A BP tApE hEaDer

Then it will contain a tar-based command string similar to the tar line above since NetBackup uses a modified version of GNU tar for their backups.

Also while importing the backups, you also want to make sure to use a non-rewinging device (/dev/rmt/0mn) for the data scan. The mt command on Unix will aid that process. What I would suggest is to do is to:
1. Mount the tape
2. mt -t /dev/rmt/0mn rew (seak to the beggining of the tape)
3. dd if=/dev/rmt/0mn bs=1k of=file1
Since the dd is on the non-rewinding device, it will be positioned at the next tape make on the tape if there is one.
4. Continue to do a dd if=/dev/rmt/0mn bs=1k of=fileX until you get an end of media error.

Alternately if you want to find out how many records or backups may be on the tape, you can do:
1. mt -t /dev/rmt/0mn rew
2. mt -t /dev/rmt/0mn status
3. mt -t /dev/rmt/0mn fsr 1 (forward seek 1 record)
4. Repeat 2-3 until no more records are found. I know from experience that after the last record it will take a LONG time for the fsr command to succeed since it will seek to the end of the media looking for that record.

Hope this helps.

Jean-Yves Rouffiac
Occasional Advisor

Re: Reading HP 9000 DLT backup tape under Windows 2000

That's great, many thanks for the info and step by step guide.
:)

I am hoping to have access to the unix box either tomorrow on on Monday, so fingers crossed!

James Perry
Advisor

Re: Reading HP 9000 DLT backup tape under Windows 2000

Glad to help. Let me know if you need more assistance.
Jean-Yves Rouffiac
Occasional Advisor

Re: Reading HP 9000 DLT backup tape under Windows 2000