[Info-vax] Backup TK50 tapes

[ChrisQ]

On 02/24/13 22:52, Dennis Boone wrote:

>
> You continue to fail to get it.  It's not about how "low-level" the
> tool is.  The blocks aren't necessarily all the same size.  You may
> not _know_ the size, even if they are.  The next guy who has to pick
> up your image _probably_ doesn't know.  The size of the blocks matters
> in many cases.  If you use dd, you THROW AWAY this information, and
> save just a stream of bytes.  Don't use dd to image tapes.  Don't.
> Eh eh eh, I see you thinking about doing it anyway.  STOP.  Use a
> tool which saves this data.
>
> If you're going to use the image with a simulator, it probably wants
> .tap format or similar anyway.  A .tap image preserves the block sizes.
> There are plenty of tools for building such images.  Use one.
>
> De

You really don't need to get so excited and I beg to differ. To make it
clear, dd reads blocks, not unconnected byte streams, so providing you know
the block size, you can read and recreate the block exactly as stored, 
even if
you have to do it block by block. If you look at the TK50 on tape 
structure,
it too saves in blocks, as would be expected...

Regards,

Chris