Re: [rdiff-backup-users] Pretty pictures and new version of proposal

[Kevin Spicer]

On Mon, 2003-09-29 at 20:17, John Goerzen wrote:

>  * Some information in the archive header should be instead stored in
>    the file header.  This would allow, for instance, some files to be
>    compressed with gzip, others with bzip2, and still others with cat :-)

Yes, I was thinking something similar - but hesistated to add to the
complexity of the discussion so far!

When the archiving program is compressing blocks it could then compare
the size of the compressed block to that of the original and if it has
grown (as will be the case when compressing filesystems containing
compressed files) should throw away the compressed block and use the
uncompressed block instead - recording whether or not the the block is
compressed in its header.  This would improve overall compression
ratios.

The other issue I thought of is packing incomplete blocks with random
data, and/ or adding extra random data blocks to prevent key-discovery
by encoding of known data [obviously there is a tradeoff between size
and security here - so probably should be user-adjustable, and not done
where the archive is not encrypted.]  Similarly the archive (when
encrypted) should perhaps not archive files in a predictable order (as
some filesystems will contain substantial amounts of predictable data). 
Thoughts?




BMRB International 
http://www.bmrb.co.uk
+44 (0)20 8566 5000
_________________________________________________________________
This message (and any attachment) is intended only for the 
recipient and may contain confidential and/or privileged 
material.  If you have received this in error, please contact the 
sender and delete this message immediately.  Disclosure, copying 
or other action taken in respect of this email or in 
reliance on it is prohibited.  BMRB International Limited 
accepts no liability in relation to any personal emails, or 
content of any email which does not directly relate to our 
business.