A computer system in a network that is shared by multiple users. Servers come in all sizes from x86-based PCs to IBM mainframes. A server may have a keyboard, monitor and mouse directly attached, or one keyboard, monitor and mouse may connect to any number of servers via a switch (see
KVM switch).
In cloud computing datacenters with hundreds and thousands of servers residing in equipment racks, all access to the machines is via the network. In addition, there can be many "virtual machines" running in a single server, each virtual machine appearing and functioning as a single server to the customer that uses it (see
virtual machine and
server instance). See
server farm,
blade server and
rack mounted.
A User's Machine Can Be a Server
Stand-alone PCs and Macs can also function as a server to other users on the network even though they serve as a single workstation to one user (see
peer-to-peer). In such cases, specific folders are typically configured for sharing rather than the entire hard drive.
Servers Can Be Software Only
The term "server" may refer to both the hardware and software (the entire computer system) or just the software that performs the service. For example, a "Web server" may refer to a dedicated computer running Web server software or to Web server software running with other applications. Servers are classified by their purpose, and the following servers are defined in this encyclopedia.
application server
audio server
database server
fax server
file server
intranet server
mail server
media server
merchant server
modem server
network access server
print server
proxy server
remote access server
server appliance
streaming server
telephony server
terminal server
Web server