A mainframe is a large, powerful computer that can process requests from millions of users at the same time, whereas a microcomputer is a small computer designed to be used by one person at a time. Large organizations such as banks and government agencies use mainframe computers. Single users work with microcomputers to perform personal and work-related tasks.
Mainframe computers have been produced by companies such as IBM and Unisys since the 1950s. At that time, they were large enough to occupy an entire room. Mainframe computers are about the size of a refrigerator and cost at least $75,000. Corporations justify the expense by keeping mainframes running around the clock to handle critical tasks such as processing credit card transactions and updating airline information.
Microcomputers are smaller computers that derive their power from microprocessing chips. More commonly called personal computers, they are the most widely used type of computer. PCs include desktop computers, which are set up on a desk or similar surface and are rarely moved from one location to another. In contrast, a laptop is a portable computer with a clamshell design that allows the display screen to be folded over the keyboard. Tablets and smartphones are also intended for mobile use, but are smaller and more lightweight than laptops.