Computer Science Overview Chapter Three-Operation System (1)

1. Computer Science OverviewChapter Three-Operation System (1) JainShing Wu

2. Operating System • A collection of software • Manages computer hardware resources • Provides common services for computer programs • A vital component of the system software in a computer system

3. Operating System

4. History • Early computers were built for a series of single tasks • Calculator • In the 1940s, the earliest electronic digital systems had no operating systems • Electronic system were programmed on rows of mechanical switches or by jumper wires on plug boards

5. History • After programmable general purpose computers were invented, machine languages were introduced • Speed up the programming process

6. History • Basic operating system features were developed in the 1950s • Automatically run different programs • Hardware features were added • Use of runtime libraries • Interrupts • Parallel processing

7. History • Each user • Had sole use of the computer for limited time • Arrive at a scheduled time with program and data on punched paper cards and/or punched tape • The program would be loaded into the machine • The execution of program called job • The machine would be set to work until the program completed or crashed

8. History • Operating systems did not exist in the modern and more complex computers until the early 1960s • Batch processing

9. Queue • First in, first out (FIFO) • Jobs are removed from the queue in the order in which they arrived • Ex: Waiting zone Processing zone Finishing zone

10. History • Batch processing • Each job is accompanied by a set of instructions • These instructions are encoded using job control language (JCL) and stored in job queue • Drawback • No interaction between user and submitted job

11. History • Interactive processing

12. History • Interactive processing • Terminal (a CRT and a keyboard) • Input the command • Read the computer’s response • Serve a user at a time

13. History • Real-time processing • Early • Execute tasks under a deadline • Now • Response occur in real-time • Computer performs the task in accordance with deadlines in its environment

14. History • Real-time processing • 1960s, computers are still expensive • One user at a time (x) • More users at the same time (O) • Several users uses terminals to connect to computer at the same time

15. History • Time-sharing system • Multi-programming • Time divided into several intervals • Execute jobs one interval at a time

16. History • In the 1980s • Personal computers became popular • Operating system were made for these PCs • Similar in concept to these operating systems used on larger computers

17. Type of Operating System • Micro-computer • PC-DOS, MS-DOS, MS Windows 95, Win98, Win 2000, Win XP, Win 7, Apple Macintosh, Unix like systems, etc • Mainframe • Unix, Solaris, Win NT, Unix like systems, etc

18. Disk Operating System (DOS) • IBM PC DOS • IBM force assembled to develop the PC • Decided that critical components of the machine, including the operating system

19. PC-DOS

20. Disk Operating System (DOS) • Microsoft DOS (MS-DOS) • Written by Tim Paterson • Owned by Seattle Computer Products • Original name is 86-DOS • Known as the Quick-and-Dirty Operating System or Q-DOS

21. MS-DOS

22. MicroSoft Windows 95 • A consumer-oriented graphical user interface-based operating system • Separate MS-DOS and Windows products • Graphical user interface (GUI) and "plug-n-play" features • Extend 16 bits to 32 bits

23. MicroSoft Windows 95

24. Windows 98 • Windows 98 • Is Windows 95 successor • Enhances the internet ability • Includes Internet Explorer 4.01. and many other Internet companion applications

25. Windows 98

26. Windows 7 • Extends from 32 bits to 64 bits

27. Apple Macintosh • Develop by Apple Inc. • One click for software install • All hardware are not easy updated

29. Unix and Unix Like Systems • OS of Mainframe • A multitasking, multi-user computer operating system • Developed in 1969 by a group of AT&T employees at Bell Labs

30. Unix and Unix Like Systems

31. Unix and Unix-Like Systems • Direct interaction • Moving away from the total control of businesses like IBM and DEC • AT&T giving the software away for free • Running on cheap hardware • Being easy to adopt and move to different machines

32. GNU Announce • In 1983 • Richard Stallman announced the GNU project • An ambitious effort to create a free software Unix-like system; "free" in that everyone who received a copy would be free to use, study, modify, and redistribute it

33. GNU General Public License (GPL) • Derived works can only be distributed under the same license terms • GPL • Grants the recipients of a computer program the rights of the free software definition • Uses copyleft to ensure the freedoms are preserved, even when the work is changed or added to

34. FreeBSD • FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX

35. FreeBSD

36. Linux-Ubuntu • A computer operating system based on the Debian Linux distribution • Distributed as free and open source software • Desktop environment • Graphical interface

37. Linux-Ubuntu

38. QUESTION?