Operating Systems From the Ground Up

An operating system is the resource manager and abstraction layer between hardware and applications, providing processes, memory, files, and devices.

A process is an executing program with its own memory, state, and identity, tracked by the kernel through a process control block.

Visual comparison of processes and threads: memory isolation, creation cost, communication, and failure boundaries.

Follow a process from creation through ready, running, I/O wait, back to ready, and termination — the five states and how the kernel transitions between them.

Given a sequence of system calls, determine the process state transition at each step.

The interview answer covering memory isolation, creation cost, communication, and failure boundaries.