[Info-vax] Backup TK50 tapes

[Bob Koehler]

In article <SqrWs.159472$1i1.11353 at fx07.fr7>, ChrisQ <meru at devnull.com> writes:
> 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