Hold is a status flag which tells apt (or aptitude) not to automatically upgrade a package.
To hold a package, 'echo pkgname +hold|dpkg --set-selections'
or 'aptitude hold package'
or use = in aptitude's curses interface.
You can ignore a hold by using apt-get install foopkg; or by using ++ in aptitude's curses interface.
[Note that this is *NOT* the same as packages which have been "held back" for dependency reasons.]
Snapshots is an archive that contains all Debian packages uploaded since 2002,
including those removed from the official archives because they were very buggy, unusable, broken, vulnerable or in some way undistributable.
Much of 2004 was lost because of harddisk problems.
See http://snapshot.debian.net/ for more information.
e.g.
dpkg -i /var/cache/apt/archives/sun-java5-bin_1.5.0-14-3_i386.deb /var/cache/apt/archives/sun-java5-jre_1.5.0-14-3_all.deb
aptitude hold sun-java5-bin
aptitude hold sun-java5-jre
Thanks to #debian
