D-SP-Ch1-Basic_OS_Concepts

Computer System

A computer system is fundamentally an integrated collection of components that work together to process, store, and communicate information automatically

• D-SP-Ch1a-Computer_System

Operating System

Vertical View: It is an extended machine

• Present user with a virtual machine - this allows developers no need to rewrite programs when switching to different hardware (since different hardware has different ISA)

• UNIX Architecture

• System Calls vs. Function Calls

• Modes of Execution

• System Memory (User Space vs. Kernel Space)

Horizontal View: It is a resource managaer

• Manage hardware resources: CPU, memory, I/O devices

• Each program gets time using the resource and space on the resource

• OS makes sure programs have a fair use on the resource

• Act as interface for user to access kernel

• User Identification

• Process Management

• Directory Management