@linus Back in Uni, in the first year, we were tasked to write a simple TCP-based messenger in Java, given the protocol spec. A poor persons IRC basically. A friend's group somehow managed to ignore TCP listen and just did busy waiting - no sleep interval in between. Their program used up to much CPU that the laptop they were using to present the project ran out of battery while presenting their submission. I used that program as a small space heater in the winter back then.