UMUC CS 412, Sp 97, Introduction

 Silberschat and Gavin chapters 1, 2, and 3
Tanenbaum, chapter 1

Introduction - What is an operating system? (S, chapter 1)

First: what is a computer: 

An operating systems acts something like:

Survey of hardware components:

No universally accepted definition - perhaps just what a supplier ships

Issues: user convenience and efficiency

Evolution, mostly driven by hardware utilization and CPU vs peripheral speed:

Computer System Structure (S, chapter 2)

Bus-based systems, see S f 2.1, pg 30; plus MMU (memory management unit) and PROM or ROM (programmable read-only memory).
Boot strap program - loaded by ROM, loads OS
OS then waits for events (interrupts)

Input/output structure 


Hardware protection

Talking to OS - monitor mode from user mode

Operating System Structures (S, Chapter 3)

  1. Components
  2. Services
  3. System calls
  4. System programs
  5. System structures
  6. Virtual machines
  7. Design and implementation
  8. System generation and configuration
Components or functions. Manage: processes, RAM, secondary storage, I/O, files, security, networking and communications, command interpreter (window and line oriented control), IPC (interprocess communications)

OS services

System calls

System programs

System Structure

Virtual machines

Design and implementation

Mechanisms versus policies: what vs how

Implementation: originally in assembly language, nowadays much is in a high level language

System generation