Fundamentals

Processes vs Threads

Main : Processes are executed by threads

Memory

Stack

Stack allocation called by function Each function gets its own memory for local variables Freed immediately when function ends Too many function calls exceed stack capacity -> stack overflow error (JAVA) / segmentation fault (CPP)

Heap

Manual deallocation required Accessible by multiple threads Heap is persistent until program termination Memory leak : allocated data is not freed after use

File I/O

Concurrency

Scheduling

System Calls

 

Processes vs Threads

Process: own address space

Thread: shared address space

Context switching overhead

When threads help vs hurt

Memory

Stack vs heap

Virtual memory

Paging vs segmentation

What a segmentation fault actually is

Memory leaks and how they happen

File I/O

File descriptors

stdin/stdout/stderr

Blocking vs non-blocking I/O

Concurrency

Race conditions

Mutex vs semaphore

Deadlocks (4 conditions)

Scheduling

Preemptive vs cooperative

CPU-bound vs I/O-bound

System calls

What they are

Why they exist

User mode vs kernel mode

Practice explaining out loud

If she asks:

“What happens when a program starts?”

You should mention:

Executable loaded

Virtual memory allocated

Stack/heap setup

Entry point (main)

Syscalls for I/O