In the most basic form, pretty much any personal computer can be considered a server, depending on what software is running on it. Any computer running shared programs or databases may are considered Business Servers. The server is typically tied to a local network and other computers access the programs or databases from the network. The simplest form of a server is a common storage computer used to store shared files among multiple users.
Many small businesses operate in just this manner. However, this is a recipe for a disaster. Different computers are designed for different user expectations. A standard PC is designed for up to daily use for perhaps 10 hours a day. The computers are designed to “sleep” peripherals that are not in use. Most importantly, the hard disks are designed to sleep when not in use. So the life expectancy of the hard disks is usually considerably shorter than a commercial storage grade computer.
There are many other limitations to conventional computers as servers. Read the next section on legitimate business grade servers.
So a real business class server should have at least the following:
A reasonably good example of an entry grade “Tower” style server is a Dell PowerEdge T110 II Tower Server. However, better options are available with hosted servers. Please see our hosted server discussion here.