CPU is the major component which interprets and executes software instructions. It also controls the operation of all other components such as memory unit, input and output units.

(i) Microcomputer
(ii) Portal Computers

(i) The ALU performs arithmetic operations.
(ii) The result of an operation is stored in internal memory of CPU.
(iii) The logical operations of ALU promote the decision making ability of a computer.

The CPU has three components which are Control unit, Arithmetic and Lagic Unit (ALU) and Memory unit.

Fingerprint scanner :
Fingerprint Scanners is a fingerprint recognition device used for computer security equipped with the fingerprint recognition module feature that uses biometric technology. Fingerprint Reader/Scanner is very safe and convenient device for security instead of password, that is vulnerable to fraud and is hard to remember.

(i) Robot is a term coined by Karel Capek in the 1921 play RUR (Rossum's Universal Robots).
(ii) It is used to describe a computerized machine designed to respond to input received manually or from its surroundings.

Monitor:
(i) Monitor is the most commonly used output device to display the information. It looks like a TV.
(ii) Pictures on a monitor are formed with picture elements called PIXELS.
(iii) Monitors may either be Monochrome which display text or images in Black and White or can be color, which display results in multiple colors.
(iv) There are many types of monitors available such as CRT (Cathode Ray Tube), LCD (Liquid Crystal Display) and LED (Light Emitting Diodes).
(v) The video graphics card helps the keyboard to communicate with the screen.
(vi) It acts as an interface between the computer and display monitor.

(i) Computer is the powerful machine.
(ii) It can perform large number of tasks
(iii) The main capacities of computer are work length, speed accuracy, diligence, versatility memory and automation and lots of more tasks.

Registers:
(i) Registers are the high-speed temporary storage locations in the CPU. Hence, their contents can be handled much faster than the contents of memory.
(ii) Although the number of registers varies from computer to computer, there are some registers which are common to all computers. Five registers that are essential for instruction execution are:
(iii) Program Counter (PC): Contains the address of the next instruction to be fetched.
(iv) Instruction Register (IR): Contains the instruction most recently fetched.
(v) Memory Address Registers (MAR): Contain the address of a location in memory for read and write operations.
(vi) Memory Buffer Register (MBR): It contains the value to be stored in memory or the last value read from memory.
(vii) Accumulator (ACC): An accumulator is a general purpose register used for storing temporary result produced by the arithmetic logic unit.

Impact Printers:
(i) These printers print with striking of hammers or pins on ribbon. These printers can print on multi-part (using carbon papers) by using mechanical pressure.
(ii) For example, Dot Matrix printers and Line matrix printers are impact printers.
(iii) A Dot matrix printer that prints using a fixed number of pins or wires. Each dot is produced by a tiny metal rod, also called a "wire" or "pin", which works by the power of a tiny electromagnet or solenoid, either directly or through a set of small levers.
(iv) It generally prints one line of text at a time. The printing speed of these printers varies from 30 to 1550 CPS (Character Per Second).

(v) It generally prints one line of text at a time. The printing speed of these printers varies from 30 to 1550 CPS (Character Per Second).

Components of a Computer :
The computer is the combination of hardware and software. Hardware is the physical component of a computer like motherboard, memory devices, monitor, keyboard etc., while software is the set of programs or instructions. Both hardware and software together make the computer system to function. Every task given to a computer follows an Input-process - output cycle (IPO cycle).

(i) Input unit: Input unit is used to feed any form of data to the computer, which can be stored in the memory unit for further processing.
Example : keyboard, mouse etc.
(i) Central Processing Unit : CPU is the major component which interprets and executes software instructions. It also control the operation of all other components such as memory, input and output units.
(iii) Arithmetic and Logic Unit : The ALU is a part of the CPU where various computing functions are performed on data. The ALU performs arithmetic operations such as addition, subtraction, multiplication, division and logical operations.

(iv) Control Unit : The control unit controls the flow of data between the CPU memory and I/o devices. It also controls the entire operation of a computer.
(v) Output Unit: An output unit is any hardware component that convey information to users in an understandable form. Example : Monitor, Printer etc.
(vi) Memory Unit: The Memory Unit is of two types which are primary memory and secondary memory. The primary memory is used to temporarily store the programs and data when the instructions are ready to execute. The secondary memory is used to store the data permanently. The Primary Memory is volatile, that is,the content is lost when the power supply is switched off. The Random Access Memory (RAM) is an example of a main memory. The Secondary memory is non volatile, that is, the content is available even after the power supply is switched off. Hard disk, CD-ROM and DVD ROM are examples of secondary memory.