Operating System Fundamentals Flashcards

What is the difference between a process and a program?

Answer: A program is static code on disk; a process is a program in execution with associated resources

A program is a passive set of instructions stored on disk, while a process is an active instance of execution with its own state.

Which system call is used to wait for a child process to finish in Unix?

Answer: wait()

The wait() system call causes the parent process to block until one of its child processes terminates.

What is 'demand paging'?

Answer: Loading pages into memory only when they are actually needed during execution

Demand paging loads a page from disk into memory only when the process accesses it, triggering a page fault.

In a file system, what is the purpose of a 'journal'?

Answer: To record pending metadata changes so the file system can recover after a crash

A journaling file system records changes to a log before applying them, enabling recovery to a consistent state after crashes.

Which of the following best describes the 'banker's algorithm'?

Answer: A deadlock avoidance algorithm that checks if resource allocation leads to a safe state

The banker's algorithm grants resource requests only if the resulting state is safe (i.e., all processes can eventually complete).

What is 'spooling' in operating systems?

Answer: Buffering data for a slow device (like a printer) in a queue so the CPU can continue other work

Spooling (Simultaneous Peripheral Operations On-Line) queues jobs for slow devices so the system can process other tasks concurrently.

What is the key advantage of using a multi-level feedback queue scheduling algorithm?

Answer: It adapts process priority dynamically based on CPU burst behavior, favoring interactive tasks

Multi-level feedback queues move processes between priority queues based on behavior, automatically favoring short/interactive jobs.