It was the moment I truly understood memcopy, memory management, and how powerful C was.
I designed several "viruses" (that's how we called them), and made them play in a tournament, which would last a few hours on his 386. Tons of fun, and tons of learning.
While Core War had some depth, in the end it seemed the most successful programs used the same pattern. First it worked as a scanner to find the enemy, then it worked as a vampire to trap the enemy process in a small loop that forces the enemy process to split repeatedly (to slow the processes that are still roaming free), then once all processes are trapped, kill them.
I wonder if there were any changes in the rulebook since the 90s that would add more variety to the game.
I remember we had an LCD projector that was literally a monochrome LCD in a frame without a back that the instructor put on top of a standard overhead projector.
C-robots was another programmable game that was lots of fun, but the simulation was not as visceral as watching the programs in Core War fight inside the memory of a virtual machine.