Lecture 1: Network Operating Systems (NOS)

1. Lecture 1: Network Operating Systems (NOS) An Introduction

2. Overview of basic networking concepts • Open Systems Interconnection model (OSI): • is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system. • network model: • PAN • LAN • MAN • WAN Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

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4. Scale(size) Based Network Classification • PAN • LAN • MAN • WAN • Internet Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

5. Personal Area Network (PAN) •  computer network organized around an individual person. • PAN involves a computer, a cell phone..etc • Using Bluetooth and USB often used to link this kind of networks. • Communication Technology: • Wired • Wireless (WPAN):(Bluetooth, infrared) Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

6. Local Area Network (LAN) • A LAN is a privatelyowned network that operates within and nearby a single building like a home, office or factory. • The connection must be high speed and inexpensive. • Size: few kilometers. Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

7. Local Area Network (LAN) • Advantages • Easy to share • Cost of LAN setup is low. • Disadvantages • Power • Security • Speed • Covers limited area. Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

8. Metropolitan Area Network (MAN) • A metropolitan area network (MAN) is a high-speed network that connects local area networks in a metropolitan area • It covers a city. • Examples: • The cable television networks available in many cities. Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

9. Metropolitan Area Network (MAN) • Advantages • Efficiency and shared access. • All the computers residing in the same area have an equal chance to access the network. • Disadvantages • costly • Security problems • slow. Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

10. Wide Area Network (WAN) • A wide area network (WAN) is a network that covers a large geographic area (such as a city, country, or the world) using a communications channel that combines many types of media such as telephone lines, cables, and radio waves. Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

11. Wide Area Network (WAN) • Advantages • Increased efficiency. • Ease of communication. • Disadvantages • Security problems. • Training costs. • Maintenance problems Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

12. Introduction to Operating Systems Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

13. What is an Operating System? • 2 kinds of a software – Application Software • Word processors, database manager, compiler, web browser – System Software • Operating system itself • Bridges between the hardware and users Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

14. Functions of Operating Systems (OS) • Resource management • • Memory management • • Device management – Printer – Hard drive – display • • Process management • • Processor management (CPU time ) Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

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16. Why OS was Born? Batch processing – Resident Monitor Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

17. Time Sharing Using Operating Systems Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

18. Operating Systems • Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources. Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

19. Operating Systems • Operating system (OS) is a software that manages computer hardware and software resources and provides common services for computer programs. • Operating systems form an essential component of the system software in a computer system. • Application programs usually require an operating system to function. Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

20. Operating Systems • For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware. • Operating systems can be found on almost any device that contains a computer—from cellular phones and video game consoles to supercomputers and web servers. Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

21. Operating Systems: Examples • Examples of popular modern operating systems include: • Android, BSD, iOS, Windows Phone, • Linux, OS X, QNX, • Microsoft Windows, and IBM z/OS. • All these examples, except Windows, Windows Phone and z/OS, share roots in UNIX. Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

22. Networks Operating Systems • Network operating system (NOS): software that implements an operating system of some kind that is oriented to computer networking. • The network operating system is designed to allow shared file and printer access among multiple computers in a network Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais

23. NOS Characteristics Network operating systems (NOSs) distribute their functions over a number of networked computers. It adds functions that allow users to access shared resources concurrently. Client systems contain specialized software that allows them to request shared resources that are controlled by server systems responding to a client request.

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25. Differences Between PC and a NOS The NOS enhances the reach of the client PC by making remote services available as extensions of the local operating system. Although a number of users may have accounts on a PC, only a single account is active on the system at any given time. NOS supports multiple user accounts at the same time and enables concurrent access to shared resources by multiple clients (multitasking and multiuser environment).

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27. Multiuser, Multitasking, and Multiprocessor Systems A NOS server is a multitasking system. the OS is capable of executing multiple tasks at the same time. Some systems are equipped with more than one processor, called multiprocessing systems. multiprocessing systems are capable of executing multiple tasks in parallel by assigning each task to a different processor. The total amount of work that the server can perform in a given time is greatly enhanced in multiprocessor systems.

28. NOS Server Hardware NOS servers are large systems with additional memory to support multiple tasks that are all active, or resident, in memory at the same time. Additional disk space is also required on servers to hold shared files and to function as an extension to the internal memory on the system. Because a NOS depends on the continuous operation of its servers, the extra hardware components justify the additional expense.

29. Choosing a NOS The main features to consider when selecting a NOS include: Performance Management and monitoring tools Security Scalability Robustness/fault tolerance

30. Networks Operating Systems: Where to use? • NOS can be used in: • Routers, switches and hardware firewall. • PCs in Peer-to-peer networks • Client-server Architecture Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais