In summary, a microcomputer consists of a central processing unit that accepts data from an input device, processes the data, and then sends it to an output device. A typical microcomputer configuration is shown in Figure 1.6. When a microcomputer is first turned on, its memory is empty. Before it can begin processing any data, the data must somehow get into the memory of the microcomputer. The four most common methods of entering data into a computer are shown below.
Information is typed in from the keyboard.
Data are read in from secondary storage devices like floppy disks, hard disks, or tape drives. Data are collected and entered into the computer from interface devices such as analog to digital converters. Most information that is processed by a computer originally gets into the computer by being typed in from a keyboard. Therefore, most of this section will be devoted to describing the standard IBM PC keyboard, illustrated in Figure 1.7. The keyboard is divided into three sections.