Chapter 13 – Processes vs Threads

Core idea

A process is an isolated execution environment; a thread is a lightweight execution unit inside a process.

Process

• Own address space
• Heavyweight
• Strong isolation
• Context switch is expensive

Thread

• Shares process memory
• Owns:
  • Stack
  • Registers
  • Program counter
• Lightweight
• Faster context switches

Why threads exist

• Better CPU utilization
• Parallelism
• Responsiveness (e.g. UI + background work)

Exam traps

• Threads ≠ safer (shared memory!)
• One process can have many threads