Here, there is a summary of what discussed on 30_12_2004 (really late in
the nigth!!) about how to implement download of binary packages, source
packages, and general extra files (documentation, ....) from remote
mirrors.

The following is an attempt to resolve the following problems:

o) how to clean old or unneeded files (cleanup)
o) how to update the mirrors managing disk space (i.e.: remove old
   unneeded files _before_ download newer files )
o) do all above in a fast way


---------------------------------------------------------
Procedure
---------------------------------------------------------
* build a list of files contained into the local mirrors

* get indices of files to download from each remote repository

* build a list of files to be downloaded (and a list of unneede files
  that shuold be given by the list obtained by difference..)

* evaluate needed disk-space and cleanup if needed/wanted

* start download


----------------------------------------------------------
Considerations
----------------------------------------------------------

Trusting:
Mirror should be trusted. This can be accomplished by tracking md5 infos
on index files (moreover those files are signed); a complete verify on
md5sums on mirrored packages can be realized when using them (via apt,
or when building iso, and so on).

Resuming:
Download manager should be sligthly modified to create tempfiles for
resume operations.
