The cpu main components Central Processing Unit

A processor or CPU, which is short for central processing unit, is the nerve centre of any digital computer system. It coordinates and controls the activities of-other units and performs all the arithmetic and logical processes. In the instruction cycle the processor carries out four commands: fetch the instruction, fetch the data (if any) upon which the instruction is to act, carry out the instruction, store the result in the memory. It repeats the same four steps with the next instruction. The link of the CPU to input and output devices is not as direct as the link to the memory. To run a disk drive, for example, the CPU has a specialized processor, a controller, that transmits instructions directly to a disk drive.

Exercises

• Read and translate the following international words and word-combinations.

Modern computers, binary machine, processor, central, centre, coordination, arithmetic and logical processes, instruction cycle, result, disc drive, specialized processor, controller.

• Give derivatives:

• to process; 8) to control;

• a centre; 9) to transmit;

• a system; 10) direct;

• to coordinate; 11) to drive;

• logic; 12) to repeat;

• to instruct; 13) to act;

• special; 14) arithmetic.

• Give English equivalents for the words in brackets.

• A processor or CPU, which is short for (центральный процессор), is the nerve centre of any digital computer system.

• CPU (координирует и управляет) the activities of other units.

• CPU performs all the (арифметико-логические) processes.

• In the instruction cycle the processor (выполняет) four commands.

• The link of the CPU (устройство ввода и вывода) is not as direct as the link to the memory.

• To run (дисковод) the CPU has a specialized processor, a controller.

• A specialized controller (передаёт) instructions directly to a disc drive.

• Answer the questions.

• What is CPU?

• Why is it called the nerve centre of any digital computer system?

• How many commands does the processor carry out in the instruction cycle?

• Is the link of the CPU to input and output devices direct?

• What does a specialized processor, a controller, do to run a disc drive?

• Read the text and find the information dealing with the CPU. Give the definition of CPU, point out its functions.

Output devices Microcomputer Hardware

In this chapter, we've described the various pieces of hardware — the physical devices — of a computer system that are used to input, process, and output data. Input devices, which range from keyboards and touch-sensitive screens to mice and light pens, translate the information into a series of on and off electrical signals. These signals, called bits, are combined in specific series to represent letters, numbers, and signals. Each series of 8 bits is called a byte.

Processing is controlled by the central processing unit (CPU), which consists of a control unit that directs the transfer of data and an arithmetic/logic unit (ALU) that performs mathematical and logical calculations. Once entered, data is moved to memory for processing — this is the information that appears on the screen — or written to the disk for permanent storage.

The system unit itself houses the processing devices, electronic circuits, and other components. Many of these devices are tiny silicon chips, also known as semiconductors or integrated circuits. These chips include the CPU, RAM (random access memory), and ROM (read-only memory); they are plugged into sockets on a printed circuit board (a board with electrical circuits printed on it). The board that contains the CPU is known as the system board (or motherboard); it provides several expansion slots that allow users to add memory and expansion boards for input and output devices (peripheral devices) such as mice, monitors, modems, and scanners.

Read-only memory (ROM) contains the computer's built-in instructions; the computer can read but not alter the contents. Random access memory (RAM) allows the manipulation of data; if the program is ended or the power turned off before the changes have been saved, all new material is lost.

Microcomputers typically include a hard disk (HD) and one or two floppy disk drives. The hard disk provides greater storage space and speed than a floppy disk (FD) provides; it is usually scaled within the unit (some removable driven are available) and contains the operating system and whatever programs and data you choose to write to it. Because hard disks can malfunction (crash), it is advisable to back up their data onto floppy disks (or tape) to be stored outside the system. Other storage devices include optical discs, where the data has been burned onto the disc by means of a laser, and interactive video.

Input and output devices, connected to the system unit through serial ports, parallel ports, and specialized ports, let the user interact with the system to input data and receive processed results. Common input devices include the keyboard, mouse, scanner, and tight pen; common output devices include the monitor, printer, and plotter. The modem functions as both as input and output device.