up:: Fundamentals of Operating Systems prev:: Chapter 2 – System Architecture next:: Chapter 4 – Process Execution (Fetch–Execute Cycle)

Chapter 3 – Programs vs Processes

Core idea

A program is static; a process is a program in execution.

Program

• Compiled executable file
• Lives on disk
• CPU-architecture specific
• At rest

Process

• Program loaded into memory
• Has:
  • PID (process ID)
  • Program Counter (PC)
  • Registers
  • Memory layout
• Multiple processes can run the same program

Memory layout (conceptual)

• Text (code)
• Data (globals/statics)
• Heap
• Stack