So believe it or not in 1984 when I was in high school, I met a Sargent in the Army who did something with computers, I went to his house to check out all his computers, well, being the future hacker that I thought I was. I watched intently him login to the Forts system. I was like wow!!!
So, when I got home, in my awesome 300 bps speed, I logged into the system. I learned a lot of commands quickly. I decided to see what could be done...so I wrote a short script to create two directories and then change into on of them...for ever.
Needless to say for the time, the system was "quite fast" well, with about 3 minutes the system logged me out. Then a couple of hours later, I heard my dad talking about how the Forts computer system was attacked from the outside and they didn't currently know who it was. Well, my directory changing script shut down the system for a day.
I know today, this is nothing compared to what people do, but this was 1984....