Conversation so far:
is edf really a dynamic priority scheduling algorithm
Earliest deadline first (EDF) or least time to go is a dynamic priority scheduling algorithm used in real-time operating systems to place processes in a priority queue.
how does edf work
Whenever a scheduling event occurs the queue will be searched for the process closest to its deadline. This process is the next to be scheduled for execution.

Question: what makes the algorithm optimal
Self-contained rewrite: what makes edf optimal