The PC is although the most popular computer system, there are other computer systems too, which are categorized on the basis of size, cost and performance.
Before we describe some of these computer systems, it is essential to understand the term system. A system is a group of integrated parts that have a common purpose of achieving an objective. These parts or components of the PC system will be discussed in detail later in the course.
A popular computer system is the mini-computer, which is a small, general-purpose computer. It can vary in size from a small desktop model to the size of a small filing cabinet. A typical mini system is more expensive than a PC and surpasses it in storage capacity and speed. While most PCs are oriented towards single users, mini systems are usually designed to simultaneously handle the needs of multiple users, i.e. more than one person use a mini-computer at the same time.
A mainframe is another form of a computer system that is generally more powerful than a typical mini system. Mainframes themselves may vary widely in cost and capability. They are used in large organizations for large-scale jobs.
However, there is an overlap between the expensive minis and small mainframe models in terms of cost and capability. Similarly, there is an overlap between the more powerful PC systems and the mini computer.
At the end of the size and capability scale are the supercomputers. These systems are the largest, fastest and the most expensive computers in the world. They are used for complex scientific and defense applications.