Lecture 1: Network Operating Systems (NOS) An Introduction

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

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

Local Area Network (LAN) A LAN is a privately owned 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

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

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

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

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

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

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

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

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

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

Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais 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

Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais 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

Created By Dr.Najla AlNabhan edited by Maysoon AlDuwais 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

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

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

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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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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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.

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.

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

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