RE: Using Linux dd to create a tape image from MV Pro Dat Tape

[Jim Holloway]

What's the specific syntax he's using?

Try something like:

dd if="/dev/st0" of="MyMV.vtf"

This should work for most you may need to also specify a block size.

Regards,

-Jim

-----Original Message-----
From: jB...@googlegroups.com [mailto:jB...@googlegroups.com] On Behalf
Of T.Turkington
Sent: Tuesday, June 14, 2005 6:54 PM
To: jB...@googlegroups.com
Subject: OT: Using Linux dd to create a tape image from MV Pro Dat Tape


My boss is trying to create a file image of an MV Pro SAVE Dat Tape
using the dd command (on Linux, version unknown). He plans to then
T-ATT to the file image from Windows JBase. The Linux box doesn't have
JBase installed, and my understanding is the Windows box doesn't have a
Dat drive. He's getting nowhere with this as the dd command appears to
think there's nothing on the tape. Just wondering if any of the linux
experts out there might've had any experience with this, whether they've
had any success using dd (or perhaps cpio) to get an image from a legacy
Pick system... Any advise would be appreciated.

Thanks,

Tom

[Jim Idle]

I presume the following:

1) You have a DAT file save image from MV Pro;
2) A Linux system with a DAT drive;
3) The DAT drive is able to read the format of the DAT tape (DDS 2 etc) - stop here if it is not compatible;

Now, assuming that the DAT drive can read the type of DAT you have been given, you also need to cope with the fact that the drive will be in variable block size format. Therefore you have to select a device to use that allows this, or depending on the version of UNIX, modify a drive parameter or a config somewhere to ensure that it will accept variable length records. The device notes on jBASE tell you about this somewhere.

Now, the next thing is you have to use the norewind device. Otherwise you will dd and because filesaves quite often have 2 T-WEOF markers the dd will stop immediately and rewind. You can either use the mt command to skip the end of file markers, or just dd file1, file2, file3 etc until there are no more. The big one you get will be the save ;-)

Nothing to it eh?

Jim


________________________________

[T.Turkington]

Thanks, Jim.  I believe 1,2,3 are true, but my evidence is just hearsay.  (Maybe he'll chime in with the details...) I told him about making sure to use the no-rewind device, but I really didn't know which device he should use (and my recollection about unix tape devices is old, fuzzy, and otherwise incompetent (sort of like me...)).  I believe he was using /dev/rmt0 (or the corresponding no-rewind device), but as I remember there can often be various /dev/ files that correspond to the same device, that actually have different functions(?).  I did review the jbase tap2_troubleshoot.htm, and note the recommendation to execute:

 

 tapecntl -v /dev/rmt/devicename

 

From reviewing this command I assume he can also use "tapecntl -p 2" to move the tape past the first 2 T-EOF's(?).

 

If anyone can advise re: which /dev file he should be using for a linux dat drive, t'would be appreciated.  Otherwise, again thanks for this (and Jim Holloway's) advise.

 

Tom

[Jim Idle]

The device name on most versions of UNIX is more likely to be something akin to:

 

/dev/st0   - rewind device

 

Then you might find a:

 

/dev/nst0 – no rewind device.

 

Or

 

 

It would help if you could tell us what linux build you are using. But check out the man pages for stinit too and look at:

 

ls /dev/*st*

 

Though I am sure that Mark is not so old that he can’t figure that one out ;-)

 

Jim

 

 

 

---

[T.Turkington]

FYI, he's fairly convinced that the missing link was the 'tapecntl -v ...' command, but apparently has to wait a few hours before he can try again.  Anyway, thanks again.

 

Tom

[Mark Hogden]

The OS was/is an older(pre-Novell) version of SuSE, and unfortunately neither tapecntl or stinit seem to be part of that implementation.

 

The client rounded up another tape drive and we restored the data onto a windows box with account-restore and restore-all.

 

Interestingly (or not) RESTORE-ALL only seemed to work after the first ACCOUNT-RESTORE. I tried all sorts of T-FWD, T-RDLBL combinations at the front of the tape, but that's what worked, and speedily too.

 

Thank you one and all, especially Jim, who now only owes me 10 beers.

 

Mark

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From: jB...@googlegroups.com [mailto:jB...@googlegroups.com] On Behalf Of T.Turkington

Sent: Wednesday, June 15, 2005 9:10 AM

[Jim Holloway]

Mark,

 

No offence, but Jim and I have been doing these for years, (mostly Jim I), and ‘dd’ works (with the right params) (tapecntl or stinit aren’t necessary), especially for a simple MV Pro save - Glad you found another way around it though. I’m only posting this really for the archive.

 

Regards,

 

-Jim

 

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