Hey, Emacs, we're -*-Text-*- mode!

This directory contains a patch for KBackup-1.2.11 to fix it such that
it works with ftape-3.x and beyond. See the end of this file for
further explanations.

KBackup has a home page at http://KBackup.home.ml.org/

Copyright
~~~~~~~~~
The patch was provided by Sergio Ballestrero <sergio@pratonext.it>
under the GNU public License in the hope that it will be useful, but
without any warranty. For details the file `COPYING' in the top level
directory of this distribution.

Warning
~~~~~~~
This patch hasn't been tested with other tape drives or backup devices
than `ftape-3.x' or `ftape-4.x'. It isn't known whether it breaks
KBackup in a way that it doesn't work any more for other backup
devices than ftape.

[However, looking at the patches provided by Sergio I don't have the
impression that this is the case, cH]

How to apply it
~~~~~~~~~~~~~~~
The patch was produced with "diff -u". To apply it to your KBackup
distribution, you need to change to the directory where KBackup is
installed in (usually "/usr/KBackup"), and apply it with the `patch'
command like follows:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
gunzip -c KBackup.diff.gz | ( cd /usr/KBackup ; patch -p1 -l -s )
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Of course, the above example assume that KBackup is installed in
`/usr/KBackup/', and that you have changed to the directory that
contains the patch file `KBackup.diff.gz'.


Outline of changes
~~~~~~~~~~~~~~~~~~
The basic problem was that one needs to specify input AND output block
size for the `dd' program, and that one needs to avoid `cat' to write
data to or read from the backup device. `cat' doesn't use a fixed
block size. As KBackup sometimes uses pipes to transfer data to and
from the backup devices, there is a `natural' IO block size of 4k
(under Linux). IMHO this is the only reason that KBackup works at all
with tape drives. All Linux tape drives -- with the exception of
ftape-2.x and a SCSI tape drive used in variable block size mode --
use a fixed IO size.


Claus Heine

 LocalWords:  KBackup ftape Sergio Ballestrero sergio pratonext cH diff usr gz
 LocalWords:  gunzip cd dd Linux IMHO http org
