[Info-vax] Backup TK50 tapes

[ChrisQ]

On 02/24/13 15:35, Johnny Billquist wrote:

>
> That will totally not create anything useful for him.
> Unix, in all it's "glory" really sucks at some things. Record-oriented
> devices is one of those things.
> If you use dd, you'll have a lot of digging to do later, in order to get
> something useful out of the results.
>
> Johnny
>

dd is about as low level as is possible to get, so if you know the block
size, then dd will faithfully read the tape with each block as a stream
of bytes. afaics, there's nothing magic about a vms format tape, it's
still just a series of blocks on tape.

There was an earlier posting by Glen Herrmannsfeld in this group
some months ago on just this problem:

>> 2) Use 'dd' to suck the entire tape into an image file under Linux
>> and then mount it somehow under SIMH/VMS
>
> dd with a large value for the bs parameter (not ibs and obs separately)
> will preserve the block structure in a tape to tape copy, though there
> are other programs with names like tcopy that can do that. (dd will
> stop at a tape mark.) If the blocksize is constant and known,
> then a dd to disk can be usable, otherwise the blocking information
> is lost.
>
>> Or... do I just need to get a cheapie little Alpha with SCSI to
>> do all of this?
>
> Most likely any unix machine with the appropriate drive could do it.
> Other machines may or may not be able to do it. Most popular these
> days is a virtual tape file, as described above, written to CD-R.
>
> <snipped cd stuff>
>
> -- glen

Whatever the opinion, it's still the first thing I would try to get the
data off tape and I do still have a TK50Z, though not used for some time...

Regards,

Chris