ABSTRACT
This chapter discusses the hardware. Computers are designed to perform the particular varied tasks assigned to them. The input system converts information into a series of signals. Each signal is merely the presence or absence of a voltage or electrical current. The combination of the working memory, control, and arithmetic elements is often called the CPU. The CPU has a bus for transmitting and receiving signals, and the controllers, or modules, which are tied directly to that bus. The memory element is passive in that it merely receives data, stores them, and gives them up on demand. Devices used as memory elements include magnetic cores, magnetic drums, tape recorders, disks, and solid-state devices. A drum is essentially a continuous loop of magnetic tape. A cylinder is coated with a ferrous material similar to that used on tape. A disk is similar to a drum. Data are stored on the magnetic surface of a flat circular plate, like a phonograph record.
