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Operating System

Operating System. Designed by Shahid Hussain Memon. Operating system. The role of the operating system in a computing environment The various functions that an operating system performs The main components of an operating system Various types of operating systems 2. operating system.

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Operating System

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  1. Operating System Designed by Shahid Hussain Memon By:Shahid Hussain Memon

  2. Operating system By:Shahid Hussain Memon The role of the operating system in a computing environment The various functions that an operating system performs The main components of an operating system Various types of operating systems2

  3. operating system By:Shahid Hussain Memon An operating system (OS) is a collection of software that manages computer hardware resources and provides common services for computer programs. It is system software. Examples: windows xp,98 doc(disk operating system) Linux, etc.

  4. By:Shahid Hussain Memon Organization of a Computer System As shown in Figure 1.1, the major high-level components of a computer system are: 1. Hardware, which provides basic computing resources (CPU, memory, I/O devices). 2. Operating system, which manages the use of the hardware among the various application programs for the various users and provides the user a relatively simple machine to use. 3. Applications programs that define the ways in which system resources are used to solve the computing problems of the users (compilers, database systems, video games, business programs). 4. Users, which include people, machines, other computers.

  5. Operating system By:Shahid Hussain Memon

  6. Why Have Operating systems? By:Shahid Hussain Memon User/programmer convenience Greater resource utilization

  7. The Role of An OS By:Shahid Hussain Memon The 1st program that runs when a typical computer is turned ON, and the last one to finish running when the computer is turned OFF. It manages the Hardware and Software resources of the computer system, often invisibly. These include the processor, memory, disk drives, etc. It provides a simple, consistent way for applications to interact with the HW without

  8. Are OS’ es Essential? By:Shahid Hussain Memon No. If a computer has been designed for limited functionality (e.g. it runs just a single program all the time as in a automatic clothes washing machine), it does not require a traditional OS In limited-functionality computers, an OS just adds to the overhead unnecessarily, which impedes the computer’s performance In these situations, the required parts of the OS are integrated into the the only program that is going to run

  9. In the beginning … By:Shahid Hussain Memon A single user ran a single program ran on a single computer – there was no need for an OS Then came computer operators who ran multiple programs for multiple users one after the other – still, no need for an OS Later computers became powerful, & became able to run multiple programs, simultaneously. That’s when the need for OS’es arose for: Managing the resources of the computers efficiently Making use of computers convenient for users/programmers

  10. Software By:Shahid Hussain Memon A set of instructions given to the computer to solve a particular problem is called software. There are two types of software. System software. Application software.

  11. Application software By:Shahid Hussain Memon Application software: Those software which specially used for user purpose without application software we can easily operate our computer. Example: Ms word, Adobe Photoshop

  12. System software By:Shahid Hussain Memon Those software which specially used for system purpose without system software we can not easily uses our computer. Example: Windows, driver etc.

  13. Types of system software By:Shahid Hussain Memon • Operating system. • Device Drivers • Utility Programs • Language Translator

  14. Devices drivers By:Shahid Hussain Memon Small program that tells operating system how to communicate with a device.

  15. Utility program By:Shahid Hussain Memon System software that performs a specific task. A software that helps the user to solve the specific problems related to hardware or software is called utility program. Antivirus File viewer Disk scanner Screen saver

  16. Language translator By:Shahid Hussain Memon Programs that take code written in a High level language and translate it into a low-level language that is easily understood computer .

  17. Types of language translator By:Shahid Hussain Memon 1. Compiler translates the program written in a HLL in one go. The translated code is then used by the uP whenever the program needs to be run 2. Interpreter translates the HLL program one statement at time. It reads a single statement, translates it into machine language and passes that machine language code to the uP and then translates the next statement, and so on

  18. Core Tasks of an OS By:Shahid Hussain Memon Processor management Memory management Storage management Device management Application Interface User Interface

  19. Processor Management By:Shahid Hussain Memon Multiple Runs the programs of computer to manage the os.

  20. Memory Management By:Shahid Hussain Memon Each app must have enough private memory in which to execute App can neither run into the private memory space of another app, nor be run into by another app Different types of memory (e.g. main, cache) in the system must be used properly, so that each app can run most effectively

  21. Storage Management By:Shahid Hussain Memon The OS manages storage through one of its sub-modules, the File Manager file Manager is a component of O.S File Manager is the manage file system. In which files & directories, subdirectories where are them. A file system is a collection of directories, subdirectories, and files organized in a logical order. File manager maintains an index of the filenames & where they are located on the disk. File manager make it easy to find the required file in a logical and timely fashion.

  22. Device Management By:Shahid Hussain Memon Applications talk to devices through the OS and OS talks to and manages devices through Device Drivers Example: When we print to a laser printer, we do not need to know its details. All we do is to tell the printer device driver about what needs to be printed and it takes care of the details

  23. Application Interface By:Shahid Hussain Memon App developers do not need to know much about the HW, especially the uP, while they are developing their app The OS provides all apps with a straight-forward and consistent interface to the HW Example: An app uses the OS to store data on the disk drive. For that, the app does not need to know about the exact physical characteristics of that drive; it just tells the OS to do that through the app interface, and the OS takes cares of all the details of the task

  24. User Interface By:Shahid Hussain Memon Users communicate with the computer using a consistent user interface provided by the OS This UI can be a command-line interface in which a user types in the commands.

  25. OS Components By:Shahid Hussain Memon Loader Kernel Device Manager File Manager Interpreter (Shell) GUI Loader

  26. Kernel By:Shahid Hussain Memon The heart of the OS Responsible for all the essential operations like basic house keeping, task scheduling, etc. Also contains low-level HW interfaces Size important, as it is memory-resident

  27. Types of OS’es By:Shahid Hussain Memon • Classification w.r.t. the type of computers they run on and the type of applications they • Real-Time Operating System (RTOS) • Single-User, Single Task • Single-User, Multi-Tasking • Multi-User

  28. Real Time operating system By:Shahid Hussain Memon • Real time system: A system that produce output for a given input within a well defined time period. else the output is useless. • A real time system has well defined, fixed time constraints, and if the system does not produce output for an input within the time constraints, the system will fail. • Often used as a control device in dedicated applications such as medical imaging system. Industrial control systems. plane landing system, • Process control in nuclear power plants.

  29. Types of Real time system By:Shahid Hussain Memon 1. Hard real time system. 2. Soft real time system.

  30. A hard real time system By:Shahid Hussain Memon A hard real time system guarantees that critical tasks be completed on time. This goal requires that all delays in the system be completed on time. This goal requires that all delays in the system be bounded, from the retrieval of stored data to the time it takes the operating system to finish any request made of it.

  31. soft real time system, By:Shahid Hussain Memon soft real time system, where a critical real-time task gets priority over other tasks, and retains that priority until it completes. As in hard real time systems,

  32. RTOS (1) By:Shahid Hussain Memon Used to run computers embedded in machinery, robots, scientific instruments and industrial systems Typically, it has little user interaction capability, and no end-user utilities, since the system will be a "sealed box" when delivered for use Examples: Wind River, QNX, Real-time Linux, Real-time Windows NT

  33. RTOS (2) By:Shahid Hussain Memon An important part of an RTOS is managing the resources of the computer so that a particular operation executes in precisely the same amount of time every time it occurs In a complex machine, having a part move more quickly just because system resources are available may be just as catastrophic as having it not move at all because the system was busy

  34. Single-User, Single Task By:Shahid Hussain Memon OS’es designed to manage the computer so that one user can effectively do one thing at a time Example: Doc(disk operating system)

  35. Single-User, Multi-Tasking By:Shahid Hussain Memon Most popular OS Used by most all PC’s and Laptops Examples: Windows, Mac OS, Linux Lets a single user interact with several programs, simultaneously

  36. Multi-User By:Shahid Hussain Memon A multi-user OS allows many users to take advantage of the computer's resources, simultaneously The OS must make sure that the requirements of the various users are balanced, and that the programs they are using each have sufficient and separate resources so that a problem with one user doesn't affect any of the other users Examples: Linux, Unix, VMS and mainframe OS’es, such as MVS

  37. How many different OS’es are there? By:Shahid Hussain Memon 100’s OS’es from the Windows family dominate the desktops and run on millions of PC’s OS’es from the Unix family (Unix, Linux, etc) are quite popular on servers

  38. Personal computer operating system By:Shahid Hussain Memon The personal computer operating system are also called stand alone operating system or single user operating system operating system. These operating systems are used operate personal computer. Example: 1.DOS .2 Mac Os 3. Windows

  39. Doc (Disk operating system) By:Shahid Hussain Memon It is a single operating system. It is command line interface operating system. It was developed by Microsoft for IBM (internal Business Machines) in 1981. It was the most popular operating system in microcomputers before windows

  40. Disk Operating system By:Shahid Hussain Memon

  41. Mac Os By:Shahid Hussain Memon Mac Os is developed by Apple corporation in 1984 for Macintosh computers This operating system provides the GUL (graphical user interface) It was one of the first operating system that introduced the GUI.

  42. Mac Operating System By:Shahid Hussain Memon

  43. Windows By:Shahid Hussain Memon Windows is a popular operating system used in personal computers. It is developed by Microsoft corporation of USA.It is a GUI O.S. It is friendly O.S It is very easy to learn & to operate. It provides commands and application programs in the form of small pictures called icons.

  44. Windows Operating system By:Shahid Hussain Memon

  45. Windows Version By:Shahid Hussain Memon Windows has different versions such as windows 95,windows 98 and windows 2000 and windows 2003 server etc. Windows XP (Experience)

  46. Computer Networks By:Shahid Hussain Memon Network. Two or more than two devices or computer connected to each other is called network. Multiple computers that are connected together to share information and other resources. Advantages of Computer Network.

  47. Network Interface Cards (NIC) By:Shahid Hussain Memon –I/O device that plugs into the computer –Enables it to communicate over a network

  48. Protocol By:Shahid Hussain Memon It is a computer language. Protocol is a set of rules and procedure for communication. Networks use protocols, or rules, to exchange info through shared channels Protocols prevent collisions of packets caused by simultaneous transmission between two or more computers

  49. Types of computer Networks By:Shahid Hussain Memon • According to the network access policy. • Private • Public

  50. Private Network By:Shahid Hussain Memon Organizations having many computers usually connect them in the form of private networks • • Organizations having many computers usually connect them in the form of private networks

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