NETWORK OPERATING SYSTEMS SOFTWARE

Maintaining status information of many of the processes Error reporting Service initialization and service termination of workstations Network Interfaces The network interfaces provide the low-level subnet protocols and basic translation for bridging hardware drivers with the network operating system. In sophisticated systems, the network interfaces can also provide for bridging a new network into an operating network without having to rebuild the operating system. File Systems The file system controls the way the data is organized, stored, and retrieved from the storage systems available to the network. The files may be stored on hard drives, RAM disks, or optical storage devices, such as CD-ROM or write once, read many (WORM) drives. File systems are generally designed to provide universal applicability. This means that the file system can be compatible with any application program’s expectation of file input/output protocol. When adaptable interfaces are used, the file system can appear to emulate a number of different file systems. System Extensions The system extensions define the openness of the network operating system and are used by third party developers to produce add-on products. The extensions are usually high-level protocol handlers that perform operations, such as file access protocol translations required by different operating systems. The extensions available also include network management, system tools, and data-base services. System Services Network system services contain all services that are not easily defined by any of the other areas of the network. Examples of network services are security, system reliability features, error conditions, and access violations. N E T W O R K O P E R A T I N G S Y S T E M S SOFTWARE The most important job of a network operating system (NOS) is to provide file service for the attached computers. This allows information retrieval and usage and the storage of data in a shared environment. A NOS manages the other resources shared by the network and provides the following functions: Directory structure for shared hard disk storage devices File service for sharing and using data Interface to the network for application software/programs The means by which the network manager manages the network and its users Network security and data protection Communications with other networks The types of network operating systems include full-featured, low-cost, and zero-slot operating systems. Full-Featured Network Operating Systems Most full-featured network operating systems allow for high performance, flexibility, and excellent security measures. They require a LAN administrator. They require network interface cards. Also, they can be quite costly. Examples of a full-featured NOS are EtherNet, Novell’s NetWare, 3Com’s 3+Share, IBM Token Ring Network, and Banyan’s Vines. 8-13