[Info-vax] Backup TK50 tapes

[David Froble]

Stephen Hoffman wrote:
> On 2013-02-24 16:02:55 +0000, Dennis Boone said:
> 
>>  > While i'm sure there are more modern utilities to copy tapes, 
>> providing
>>  > you know the block structure of the tape, dd should copy it verbatim,
>>  > even if you have to write a script to read it block by block.
>>
>> NO NO NO!
>>
>> I love dd and all, but it THROWS AWAY BLOCK STRUCTURE and leaves you with
>> a byte stream.  The block structure is important on tapes.
>>
>> Don't use dd to image tapes!
> 
> OP: see <http://simh.trailing-edge.com/docs/simh_magtape.pdf> for some 
> details.  Tapes can have variable block sizes, and VMS tape kits use 
> that mechanism.
> 
> Much of this stuff has been discussed in the simh archives, too.  See 
> <http://www.mail-archive.com/simh@trailing-edge.com/msg00130.html>, and 
> probably some others.  (That mailing list archive is also available at 
> trailing-edge.com, but I don't have the direct link to that thread 
> handy.)  There are other threads and other tools discussed over there, too.
> 
> FWIW, if you're not already familiar with the simh archives, they 
> contain a wealth of information on tapes and tape images, and other 
> related topics.
> 
> I've dusted off an old posting on tape tools 
> <http://labs.hoffmanlabs.com/node/810>, with some pointers to tools.
> 
> ...But hauling around a bootable disk image containing the installation 
> files — with just the kit files and not the rest of the tape baggage — 
> is usually the easiest way.
> 
> 

A bootable stand alone BACKUP could be useful.  If you don't have any 
VMS, then it's a proven method for restoring the "A" saveset.