File server

The growth in desktop computing since the 1980s has resulted in much data being moved from mainframe com-puters to desktop PCs, which are now usually linked by networks. While a network enables users to exchange files, there remains the problem of storing large files or collec-tions of files (such as databases) that are too large for a typi-cal PC hard drive or that need to be accessed and updated by many users.

The common solution is to obtain a computer with large, fast disk drives (see also raid). This computer, the file server, is equipped with software (often included with the networking package) that serves (provides) files as requested by users or applications on the other PCs on the network. (See also client-server computing.) The specifics of configuring the server for optimum efficiency, providing adequate security, and arranging for backup or archiving varies with the particular network operating sys-tem in use (the most popular environments are Windows NT, Vista, and the various versions of UNIX and Linux).

The file server has many advantages over storing the files needed by each user on his or her own PC. By storing the files on a central server, ordinary users’ PCs do not need to have larger, more expensive disk drives. Central storage also makes it easier to ensure that backups are run regu-larly (see backup and archive systems).

There are some potential problems with this approach. With central storage, a failure of the file server could bring work throughout the network to a halt. (The use of RAID with its redundant “mirror” disks is designed to prevent the failure of a single drive from making data inaccessible). As the network and/or size of the data store gets larger, multiple servers are usually used. The performance of a file server is also greatly affected by the efficiency of the cach-ing mechanism used (see cache).

As the amount of data that must be stored increases, organizations will consider storage area network (SAN) and network attached storage (NAS, see networked storage) technologies. SAN makes it easier for numerous users to share a resource such as an automated tape library or disk RAID, while NAS is an efficient way to allow files to be cen-trally stored but readily shared.

All but the simplest servers require special software or extensions to the operating system. For example, Microsoft Windows Server is essentially a version of Windows with built-in facilities for managing a file or application server, including the ability to organize “clusters” of servers and balance the load of requests. Linux often comes in server versions as well, though this is basically simply a distribu-tion preconfigured with the programs needed to manage servers (such as Samba).

Meanwhile, the reason for having a file server is chang-ing. Cost of storage is much less of an issue for smaller offices with the recent availability of high-capacity drives (500 GB or more) starting at approximately $100. However, a central server still may offer better security and can serve as a central repository from which documents or source code can be “checked out” and updated in an orderly way (version control).