Servers are powerful, central network computers that are used to implement functional and infrastructural network services. For example, servers perform dedicated tasks, support network administration, manage files, domains and names, translate protocol-related instructions, ensure that e-mails and faxes are sent, and perform security-related functions.
The performance of servers
Servers are usually the most powerful and best-performing computers in a network. They have large hard disk capacities, a fast central processing unit( CPU), 64-bit technology and possibly various coprocessors. Servers are usually housed in expandable cases, which also allow for later upgrading, so-called scale-up, with new storage media or modules. Smaller servers with little computing power are called micro servers.
In addition to the usual external storage units with hard disk drives and solid-statedrives, servers can also have tape drives, jukeboxes to adequately perform one of their most important functions, automatic backup. Some parts of the servers can be designed to be fail-safe. For example, the NetWare and LAN Managernetwork operating systems support mirrored disks or dual disk subsystem design. Since fail-safety is a high priority, it is ensured in the supply by UPS systems.
The designs of servers
Servers can be built as modular single board computers, like the blade server, or as a cluster of many dedicated servers, as it is the case in the server farm, or of different functional units, as in the brick server.
The most important program on the server is the network operating system. This software allows the shared orderly use of resources (at least print and file sharing) and the installations of software for the implementation of additional services. Depending on the network operating system, the servers do not need another operating system of their own. However, there are network operating systems that run like an application program under another operating system.
The client-server architecture can also be applied to other types of computers. For example, a mainframe can become a file server and print server for a number of LAN servers, which then take on the role of clients. In this way, the advantages of a mainframe environment, such as high security, can also be made available to all LAN users.