Servers Server usually refers to a computer that is dedicated to providing one or more services. A server is expected to be reliable (e.g. error-correction of RAM; redundant cooling; self-monitoring, RAID), fit for running for several years, and giving useful diagnosis in case of an error. For even increased security, the server may be mirrored. Many smaller servers are actually personal computers that have been dedicated to provide services for other computers. • A database server is a server which uses a database application that provides database services to other computer programs or to computers. Database management systems (DBMSs) frequently provide database-server functionality, and some database management systems (such as MySQL) rely exclusively on the client–server model for database access while others (such as SQLite) are meant for using as an embedded database. Users access a database server either through a "front end" running on the user's computer – which displays requested data – or through the "back end", which runs on the server and handles tasks such as data analysis and storage. • A file server does not normally perform computational tasks or run programs on behalf of its client workstations but manage and store a large collection of computer files. The crucial function of a file server is storage. File servers are commonly found in schools and offices, where users use a local area network to connect their client computers and use Network-attached storage (NAS) systems to provide data access. • A web server is a server that can satisfy client requests on the World Wide Web. A web server can, in general, contain one or more websites. A web server processes incoming network requests over HTTP and several other related protocols. The primary function of a web server is to store, process and deliver web pages to clients. The communication between client and server takes place using the Hypertext Transfer Protocol (HTTP). Pages delivered are most frequently HTML documents, which may include images, style sheets and scripts in addition to the text content. • A terminal server enables organizations to connect devices with an RS-232, RS-422 or RS-485 serial interface to a local area network (LAN). Products marketed as terminal servers can be very simple devices that do not offer any security functionality, such as data encryption and user authentication. These provide GUI sessions that can be used by client PCs that work someway like a remote control. Only the screen (and audio) output is shown on the client. The GUI applications run on the server, data (like in files) would be stored in the same LAN, thus avoiding problems, should a client PC be damaged or stolen. A server may run several virtual machines (VMs) for different activities, supplying the same environment to each VM as if it ran on dedicated hardware. Different operating systems (OS) can therefore be run at the same time. This technology approach needs special hardware support to be useful and was first the domain of mainframes and other large computers. Nowadays, most personal computers are equipped for this task, but for long-term operation or critical systems, specialized server hardware may be needed. Another approach is to implement VMs on the operating system level, so all VMs run on the same OS instance (or incarnation), but are fundamentally separated to not interfere with each other. Workstations Workstations are computers that are intended to serve one user and may contain special hardware enhancements not found on a personal computer. By the mid-1990s personal computers reached the processing capabilities of mini computers and workstations. Also, with the release of multi-tasking systems such as OS/2, Windows NT and Linux, the operating systems of personal computers could do the job of this class of machines. Today, the term is used to describe desktop PCs with high-performance hardware. Such hardware is usually aimed at a professional, rather than enthusiast, market (e.g. dual-processor motherboards, error-correcting memory, professional graphics cards). Information appliances Information appliances are computers specially designed to perform a specific "user-friendly" function—such as editing text, playing music, photography, videography etc. The term is most commonly applied to battery-operated mobile devices, though there are also wearable devices. Embedded computers Embedded computers are computers that are a part of a machine or device. Embedded computers generally execute a program that is stored in non-volatile memory and is only intended to operate a specific machine or device. Embedded computers are very common. The majority are microcontrollers. Embedded computers are typically required to operate continuously without being reset or rebooted, and once employed in their task the software usually cannot be modified. An automobile may contain a number of embedded computers; however, a washing machine or DVD player would contain only one microcontroller. Embedded computers are chosen to meet the requirements of the specific application, and most are slower and cheaper than CPUs found in a personal computer. ==Classes by usage==

Classes of computers