BBC Micros at college
I happened to go to a school and a college that were in the pilot for the Computers for Schools project in the early 80's. This meant that I had access to a computer room with a dozen BBCs at a time when most schools only had a single machine.
Ours were running ENet rather than EcoNet, which meant that they had a central (BBC Micro) server for the admin rather than allowing the 'admin' software to be run from any of the machines.
We developed a password grabber, cracked the file storage system on the MASSIVE 20MB hard drive, and finished by obtaining a complete list of all user passwords!
Ah, the joys of youth!