USB -support - there are a few USB test kit vendors out there who provide drivers and small USB test boards. They usally read switches and light LEDs. There are USB ref docs on the web. I'd contact a vendor and see if they would help you out.

Client-server apps are documented with code in several Perl books. They usually let you send and receive a buffer full of bytes between two ports on two machines. You would add some structure to the buffer content and possibly use simple TK to display the results. You might make a master/follower mouse display or perhaps a "public scratchpad" app. Check out "Perl in a Nutshell" - Chapter 13.

The file server converter is interesting. Use hex mode in vi (or similar editor) to look at the byte by byte content of a file. Start with a simple text file. You'll see the text and the "whitespace" characters, like line feeds, spaces etc. You can use Perl to read and parse this file and then spit out a different format. Consider a simple Unix /PC converter. You might also try a simple encryption technique.

In the broader sense think about any app that needs to move info of one type to another in a consistent way. The term often used is "Data Munging" and there is a good book by that title for Perl (by David Cross). This sounds pedestrian, but a whole lot of people get paid a whole lot of money to come up with fast and accurate format conversions.

Good luck and use strict

Diskcrash