Introduction to Computer Networks Introduction to Computer Networks

Introduction to Network Operating Systems This lesson describes the basic features and functions of an NOS, and contrasts these with the capabilities of a stand-alone operating system.

Overview of NOS Network operating system software is integrated into a number of popular operating systems;Network operating system software is integrated into a number of popular operating systems; Including Windows 2000’s Server/ Professional, Windows NT Server/ Workstation, Windows XP/Me/98/95, Unix, Linux.Including Windows 2000’s Server/ Professional, Windows NT Server/ Workstation, Windows XP/Me/98/95, Unix, Linux. Each configuration—separate computer and network operating systems or an operating system combining the functions of both—has benefits and drawbacks.Each configuration—separate computer and network operating systems or an operating system combining the functions of both—has benefits and drawbacks.

Coordinating Hardware/Software and Performing Multitasking In a networking environment, servers provide resources to the network clients.In a networking environment, servers provide resources to the network clients. client network software makes these resources available to the client computer.client network software makes these resources available to the client computer. All the Network Operating systems are multitasking operating system.All the Network Operating systems are multitasking operating system. A multitasking operating system, provides the means for a computer to process more than one task at a time.A multitasking operating system, provides the means for a computer to process more than one task at a time.

Multitasking There are two primary forms of multitasking:There are two primary forms of multitasking: (1) Preemptive (2) Nonpreemptive (cooperative)(1) Preemptive (2) Nonpreemptive (cooperative) In preemptive multitasking, the operating system can take control of the processor without the task's cooperation.In preemptive multitasking, the operating system can take control of the processor without the task's cooperation. In nonpreemptive multitasking, the task itself decides when to give up the processor. In nonpreemptive multitasking, the task itself decides when to give up the processor. Preemptive multitasking system offers certain advantages in networking environment. Preemptive multitasking system offers certain advantages in networking environment.

Software Components A network operating system willA network operating system will Ties together all computers and peripherals.Ties together all computers and peripherals. Coordinates the functions of all computers and peripherals.Coordinates the functions of all computers and peripherals. Provides security by controlling access to data and peripherals. Provides security by controlling access to data and peripherals. Two major components of network software are: Two major components of network software are: Network software that is installed on clients, Network software that is installed on servers. Network software that is installed on clients, Network software that is installed on servers.

Servers A network server ties the network together A network server ties the network together

Redirector The redirector forwards requests for remote resources onto the network:The redirector forwards requests for remote resources onto the network:

Designators If you need to access a shared directory, and you have permission to access it, your operating system will usually provide several choices for how to access the directory.If you need to access a shared directory, and you have permission to access it, your operating system will usually provide several choices for how to access the directory. You could use Windows Explorer to connect to the network drive using the Network Neighborhood icon.You could use Windows Explorer to connect to the network drive using the Network Neighborhood icon. You can also map to the drive.You can also map to the drive.

Peripherals To access data on a network computer, a user need only type the drive designator assigned to the location of the resource, and the redirector determines the actual routing. To access data on a network computer, a user need only type the drive designator assigned to the location of the resource, and the redirector determines the actual routing.

Server Software With server software, users at other machines, the client computers, can share the server's data and peripherals including printers, plotters, and directories. With server software, users at other machines, the client computers, can share the server's data and peripherals including printers, plotters, and directories.

Resource Sharing Most NOSs not only allow sharing, but also determine the degree of sharing. Options for sharing include:Most NOSs not only allow sharing, but also determine the degree of sharing. Options for sharing include: Allowing different users different levels of access to the resources.Allowing different users different levels of access to the resources. Coordinating access to resources to make sure that two users do not use the same resource at the same time.Coordinating access to resources to make sure that two users do not use the same resource at the same time.

Managing Users Network operating systems also allow a network administrator to determine which people, or groups of people, will be able to access network resources.Network operating systems also allow a network administrator to determine which people, or groups of people, will be able to access network resources. Create user privileges, tracked by the network operating system, that indicate who gets to use the network.Create user privileges, tracked by the network operating system, that indicate who gets to use the network. Grant or deny user privileges on the network.Grant or deny user privileges on the network. Remove users from the list of users that the network operating system tracks.Remove users from the list of users that the network operating system tracks.

Managing the Network NOS include management tools to help administrators keep track of network behavior.NOS include management tools to help administrators keep track of network behavior.

Choosing a Network Operating System Then determine which network architecture : client/server or peer-to-peer, best meets the needs: by deciding which kinds of security are called for.Then determine which network architecture : client/server or peer-to-peer, best meets the needs: by deciding which kinds of security are called for. The next step is to determine the kinds of interoperability necessary for the network as a whole: Server-based interoperability is easier to manage.The next step is to determine the kinds of interoperability necessary for the network as a whole: Server-based interoperability is easier to manage. The first step is to determine the networking services that will be required.The first step is to determine the networking services that will be required.