IBM has historically been the main supplier, usually to large organizations that desire centralized computing. Often use a proprietary operating system. Supports somewhat fewer concurrent users than a mainframe. Servers - refers to a computer that is used to provide resources, such as files, applications, printer access to other computers.
Servers can range in size drastically, from the equivalent of a PC up to a large mainframe.
Workstations often run an operating system capable of supporting numerous concurrent users, such as Linux, Unix, or Windows NT, although they are usually used by only one person at a time. PCs - today's personal computers are more powerful than workstations of just a few years ago. Software System Software Operating system - the program that initially loads in a computer and then controls all other programs. Examples include Window 98, Windows NT, and Unix. Networking software - this is often built into the basic operating system, but in some cases may be a separate program, as in the case of Novell Netware.