To the original question
The CachePilot you have sounds to me to be the older style that contains 512MB RAM, Tyan Motherboard and a 120GB HDD and a Celeron 2.3Ghz processor, 100Mb LAN onboard
I agree with the other users its a door stop. It's running UNIX and that's all its good for.
File share don't do it, too much work for that little box.
Also if the HDD is a Maxtor Diamond Max 9 then it may be one of the drives Maxtor released with faulty controller boards so caution, they stop with no warning, the only way to get data from them is to replace the controller board.
Things it can be used for
UNIX UNIX UNIX UNIX UNIX
As a UNIX based web server with up to 40 clients, any more it will struggle.
A UNIX proxy server again up to 40 clients using at any one time.
UNIX based Print Server
UNIX based Firewall
UNIX based Email Server
Also it would most likely handle various Linux builds and all the various apps that come with them.
Things it CAN NOT be used for, not with any speed anyway
Windows OS
Windows ME/XP/2000/Vista
If you are going to use it for critical data then I also recommend you pull the lid and vacuum it out, take the system fan out located under the HDD and vacuum that out, pull the Heat sink and fan, remove the fan and wash the copper heat sink with warm soapy water, dry completely and reassemble. Take a clean 1" paint brush and brush all around the bottom of the HDD with the vacuum next to it, do the same for the motherboard.
Alternatively Espresso are more than happy to recycle it for £50 through the WEEE scheme.