In UNIX/Linux systems, what is a process called that has completed execution via exit(), but whose parent process has not yet read its exit status using wait()?
Option A is correct. A Zombie process is a terminated process whose entry remains in the process table so the parent can read its exit status code.
What occurs when a parent process terminates without calling wait(), leaving child processes running in a UNIX operating system?
Option E is correct. Orphan processes are adoption candidates in UNIX; the system re-parents orphaned processes to init (PID 1) which periodically reaps zombie children.
Which process state transition is impossible under standard operating system execution models?
Option C is correct. A process in the Waiting/Blocked state must first move to the Ready queue upon I/O completion before the short-term scheduler can allocate the CPU to transition it to Running.
What phenomenon occurs in First-Come First-Served (FCFS) CPU scheduling when short processes are delayed behind a long CPU-bound process?
Option A is correct. The Convoy Effect happens in non-preemptive FCFS scheduling when multiple small I/O-bound processes wait for one long CPU-bound process to release the CPU.
Which CPU scheduling algorithm is mathematically proven to yield the minimum average waiting time for a given set of processes?
Option B is correct. Shortest Job First (SJF) scheduling is optimal because moving a short process before a long process decreases the waiting time of the short process more than it increases the long process's waiting time.