Lecture Notes for Operating Systems

6 September 2000 - Introduction

1. What is an operating system?

   1. Provide protection

   2. Manage resources

   3. Implement virtual or extended machines - abstractions

2. History

   1. First generation - 45-55

      1. one-off, special purpose hardware - ENIAC, IBM card tabulators

      2. little support software - program libraries, loaders and linkers

   2. Second generation - 55-65

      1. big-iron hardware - mainframes

      2. software support for batch and serial processing

   3. Third generation - 65-80

      1. modified mainframes, mini- and microcomputers, internetworked machines

      2. software support for time-sharing, parallel sharing

   4. Fourth generation - 80-now

      1. first generation - pcs, ubiquitous computers

      2. second generation - batch, mainframe web servers, palm computers

      3. third generation - application program servers

3. Concepts - operating system as interface

   1. system-machine interface - processes, files, interrupts

   2. program-system interface - system calls, signals, resources

   3. human-program interface - shells, guis

4. Operating system types

   1. general purpose - supports almost any kind of processing; unix

   2. real-time - supports deadline-oriented processing; hpux

   3. transaction - supports short, well-defined interactions; tandem

   4. embedded - supports special purpose, limited resource processing; qnx

   5. distributed - supports independent but coordinated processing; amoeba

   6. emerging - supports napster; www

5. operating system structure

   1. monolithic - os360, unix

   2. layered systems - the the system, multics

   3. microkernels - mach, nt, os x

   4. virtual machines - os370, emulation mode

   5. distributed - cambridge ring

This page last modified on 11 September 2000.