While still an undergrad at Carnegie Mellon I joined the Andrew project, which was developing an advanced networked computing environment for the whole university, some components of which are still in use today.
I developed features for and maintained the Andrew Message System and Andrew Toolkit. I also created FLAMES, the Filtering Language for the Andrew Message System; achieved a 1,000x speedup in message throughput; taught classes on AMS administration; and wrote a system for demoing the Andrew system on a remote display in the pre-web days.
I was mentored by Nathaniel Borenstein, author of the MIME standard.