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Operating system


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Computer education

Published in: Education

Operating system

  1. 1. OPERATING SYSTEM By Syed Abdul Ghafoor Shah Senior Subject Specialist Govt. College for Elementary Teachers (M) Bahawalpur
  2. 2. What is OPERATING SYSTEM A Collection of system programs that controls and coordinates the overall operation of a computer system. Examples:-Microsoft windows, Linux, Unix, Sun Solaris, Mac OS
  3. 3. FUNCTIONS OF OS  Acts as interface between the hardware, application programs, files and user.  A communication link between the user and computer  Helps the user to run the application programs  Manages the computer resources (CPU, Memory and I/O devices)
  4. 4. User Application Software Operating System Hardware
  5. 5. LOCATION OF OPERATING SYSTEM A small part of operating system called “Kernel” resides in memory(Main Memory). It works in booting. Other large part of operating system is stored in secondary memory. It is swapped in or out when needed.
  6. 6. ARCHITECTURE OF OPERATING SYSTEM It consists of two major parts Operating System Control Program Service Program
  7. 7. CONTROL PROGRAM Supervisor Command Processor Interrupt Handler Input/output control System (IOCS)
  8. 8. COMPUTER Software System Software Operating System Control Program Supervisor Command Processor Interrupt Handler IOCS Service Programs Translators Service Software Application Software Hardware
  9. 9. SUPERVISOR  Major part of operating system that controls the operation of the computer  Memory Resident  Supervises the loading of other part of the operating system from Sec. to Main memory  Loads programs or data into main memory from backing storage  Scheduling the sequence of jobs to be run
  10. 10. COMMAND PROCESSOR  Accepts and carries out user commands e.g. copy , format, print
  11. 11. INTERRUPT HANDLER  Keeps track of all the process and executions of commands  Displays error massages e.g. not reading drive A
  12. 12. INPUT OUTPUT CONTROL SYSTEM (IOCS)  Monitors the operation of input/output devices  Controls and coordinates the flow of data between I/O devices
  13. 13. SERVICE PROGRAMS  Utility Programs  Library Programs
  14. 14. UTILITY PROGRAMS Enables the user to handle the file management e.g. File can easily be prepared, copied, deleted, mer.ged, so rted, updated etc
  15. 15. LIBRARY PROGRAMS Maintains directory of software and their locations
  16. 16. CATEGORIES OF OPERATING SYSTEM  Stand alone Operating System  Network Operating System  Embedded Operating System
  17. 17. STAND ALONE OPERATING SYSTEM  That works on a desktop or notebook Computer  When it works with a Network operating system is called Client Operating system Examples:-DOS, Windows XP, Windows Vista, Macintosh OS
  18. 18. NETWORK OPERATING SYSTEM  An OS that supports network  Allows to share resources such as hard disk, printer etc.  Works on network server Examples:-Windows NT Server, Windows 2003 Server, Netware, UNIX, Linux, Solaris
  19. 19. EMBEDDED OPERATING SYSTEM  It is used in hand held devices  It resides on a ROM chip  Examples:- Windows CE, Windows Mobile 2003, Palm OS
  20. 20. TYPES OF OPERATING SYSTEM  Single User  Multi User
  21. 21. SINGLE USER  This OS can run only one program at a time  Only one user is in command at any given time  It runs on microcomputers Examples:- DOS, Macintosh system
  22. 22. MULTI USER  Able to run several jobs at a time  Many users can use simultaneously  Run in main frames Examples:- UNIX, ZNIX
  23. 23. FUNCTIONS OF OPERATING SYSTEM  Memory management  Booting  Loading and execution  Disk management  Job scheduling  Device controlling  Accessing the Web  Providing interface (Command line user interface/Graphical user interface)
  24. 24. FUNCTIONS OF OPERATING SYSTEM  Controlling Network  Monitoring performance  Administrating security
  25. 25. CLASSIFICATION OF OPERATING SYSTEM OR PROCESSING METHODS  Batch Processing  Online processing  Real time processing  Multiprogramming  Multiprocessing  Time sharing
  26. 26. BATCH PROCESSING  Also known as sequential serial, Stacked processing or queued processing I. Jobs of different users are stacked in queue II. A batch of jobs when completed is sent to processor  It is low cost but time consuming
  27. 27. ONLINE PROCESSING  A job is processed at the same time when it is received Random & rapid input of transactions Immediate and direct access to record
  28. 28. REAL TIME PROCESSING  Use data as they become available  Receiving and processing of transaction is performed simultaneously and there is no delay  This system uses the features of one- line system Used in banking for account maintaining, reservation system in railways Hotels
  29. 29. MULTIPROGRAMMING There are two main disadvantages of Batch processing Under utilization of main memory Main Memory Idleness of CPU Superviso r Program-I Free Space
  30. 30. MULTI PROGRAMMING  Simultaneous Execution of two or more programs on one computer system  Computer accesses each program in turn, loading segments of each program into separate section of main storage called partition.
  31. 31. MULTIPROCESSING  When two or more processors share common memory and communicate with each other, it is called multi processing  Use of two or more CPUs within a mainframe
  32. 32. Main Memory I/O Operation I/O Operation CPU- 1 CPU- 2
  33. 33. TIME SHARING  This system allows different users to use the same CPU simultaneously by dividing CPU time among all the users on a scheduled basis.  Only one CPU  No. of terminals can be more than 100, so it is called as multi access system
  34. 34. CASE STUDY  A Pascal Program is loaded and executed with the help of operating system
  35. 35. Pascal Compiler Operating System Hard Disk
  36. 36. Turn on the PC OS is loaded Supervisor is loaded in the RAM User enters a command to load Application program The Command is interpreted by the command processor Supervisor reads the A.P into the memory Control is turned to command processor which prompts the user to enter the command User wants to read data from disk, command processor accepts the command and assigns job to I/OCS
  37. 37. Determine location of data Direct the read/write heads on disk Read the data from the disk into memory IOCS Directs the Operations
  38. 38. Control is then returned to load program The OS now waits for the next command by user If files are copied or updated Utility programs are copied to memory by supervisor