Awkward Moments in Computer Science

Some quotable gems from the last few weeks:

“I want you all to implement a PDA.” – My Computer Science Professor

Ok, ok, get your mind out of the gutter. PDA obviously stands for PushDown Automata, which is a FSM (Finite State Machine) with a stack. Now we’re working with NonDeterministic Pushdown Automata, which I like to call “No PDA” for short.

“You have to reap your zombie children.” – Another Computer Science Professor

In a UNIX environment, every time a program is launched, it must be “forked” from a currently running process. This replicates the old process, and then the new process can be modified and executed. When a process forks, the new process created becomes it’s ‘child’ process, and the original is the parent. However, when the child process terminates, it is not removed from memory immediately. In order to free up valuable space, the parent process must ‘reap’ any terminated child process, called a ‘zombie’ (because although it has stopped execution, it still remains alive in memory).

“Orphan detection and elimination.” – Same as above.

See above. This is an even sketchier way to say the same thing.

“Race conditions are bad.” – Same as above.

Race conditions, obviously, is when concurrently executing code depends on how the 2+ threads of execution are scheduled, such as two runner racing to the finish line.

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