CVSup Mirror in Deutschland

From: Wolfram Schneider <wosch(at)cs.tu-berlin.de>
Date: Tue, 14 Jan 1997 19:18:09 +0100 (MET)

Auf cvsup.de.freebsd.org (alias blues.physik.rwth-aachen.de) läuft
jetzt ein cvsup-Server. Update ist täglich gegen 6, 18 und 0 Uhr vom
Rechner freefall.freebsd.org

Die CVSup Binaries werden auf
ftp://ftp.cs.tu-berlin.de/pub/FreeBSD/CVSup/ gespiegelt.

Weitere Informationen zu CVSup siehe:
http://www.de.freebsd.org/handbook/cvsup.html

Aus ftp://ftp.cs.tu-berlin.de/pub/FreeBSD/CVSup/Announce

What Is CVSup?
--------------
CVSup is a software package for distributing and updating collections
of files across a network. CVSup is specifically tailored to
distributing CVS repositories. By taking advantage of the special
properties of the files contained in CVS repositories, CVSup is
able to perform updates much faster than traditional systems. It is
especially valuable for people with slow Internet connections.

CVSup parses and understands the RCS files making up a CVS repository.
When updates occur, CVSup extracts new deltas directly from the RCS
files on the server and edits them into the client's RCS files.
Likewise, CVSup notes the addition of new symbolic tags to the files
on the server and sends only the new tags to the client.

CVSup is able to merge new deltas and tags from the server with deltas
and tags added locally on the client machine. This makes it possible
for the client to check local modifications into his repository
without their being obliterated by subsequent updates from the server.
Note: Although this feature is fully implemented in CVSup, it will
probably not be practical to use it until some small changes have been
made to CVS.

In addition to distributing the RCS files themselves, CVSup is able to
distribute specific checked-out versions. The client can specify a
symbolic tag, a date, or both and CVSup will extract the appropriate
versions from the server's CVS repository. Checked-out versions do
not need to be stored on the server since CVSup can extract any
version directly from the CVS repository.

If the client has an existing checked-out tree, CVSup will apply the
appropriate edits to update the tree or transform it into the
requested version. Only the differences between the existing version
and the desired version are sent across the network.

To update non-RCS files, CVSup uses the highly efficient rsync
algorithm, developed by Andrew Tridgell and Paul Mackerras.

CVSup uses lightweight processes (threads) to implement a streaming
protocol across the network. This completely eliminates the delays
associated with the lock-step, request-reply form of communication
used by many existing protocols, such as sup and NNTP. Information
is transferred at the full available speed of the network in both
directions at once. Network latency and server response delays
are rendered practically irrelevant.

CVSup uses the "zlib" compression package to optionally compress all
communications. This provides an additional 65-75% compression, on
top of the diff-based compression already built into CVSup.

For efficiency, all processing is built into the CVSup package
itself. Neither the client nor the server executes any other
programs.

Wolfram
Received on Tue 14 Jan 1997 - 19:19:47 CET

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