"Apt-Cacher-NG does not require neither an interpreter,
nor a web server and not even a huge runtime library. It does never
fork after server startup, it does not create flag files, flock()
files or similar fun. Instead, it uses native system functions
(mmap, sendfile) to operate with few overhead.
"Apt-cacher-ng caches the repo’s from the different
versions of ubuntu quite nicely. It even nicely supports the
different installs of intrepid in my home with different personal
package archives (PPA, you know as in ppa.launchpad.net/*)."