incremental/delta backup

[Ben Escoto]

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>>>>> "GK" == Gautamjit Kanwar <gautamjit@hotmail.com>
>>>>> wrote the following on Thu, 04 Apr 2002 17:39:29

  GK> i need to write a remote backup software application (over the
  GK> internet like www.backupnet.com). but i am having a real hard
  GK> time finding the algorithm for calculating the changed parts
  GK> since last backup (the delta).

  GK> it seems rdiff-backup uses the same technology internally, can
  GK> someone please point me to resources on the internet for delta
  GK> calculation and implementation.

rdiff-backup just uses the standalone diffing utility "rdiff" to
calculate signatures and deltas.  rdiff is part of the rproxy project
(see rproxy.sourceforge.net) and uses the rsync (see rsync.samba.org)
rolling checksum algorithm invented by Andrew Tridgell and Paulus
Mackerras.  See Tridge's dissertation at

http://samba.org/~tridge/phd_thesis.pdf

for a discussion of the algorithm.


--
Ben Escoto

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