Components of Hardware 1

Processor Memory Input and output devices Storage 2

Processor The procedure that transfer raw data into useful information is called processing. To perform these operations computer use two components: The Processor and Memory. The Processor is like the brain of the computer; it organize the instruction comes from the user. Processor consist on silicon chips or other materials attached with many tiny electronic circuits. To process data or complete an instruction, the computer passes electricity through the circuit. 3

Circuit board is used to passes the electricity through the circuit. Circuit board and microprocessor are attached on motherboard. Motherboard called the master circuit board in the computer. All components RAM, ROM, MICROPRCESSOR, CIRCUIT BOARD, SOUND CARD, MOUSE SLOT, KEYBOARD SLOT etc attached on motherboard. 4

Motherboard 5

Memory Memory is one or more sets of chips that store data and/or program instructions, either temporarily or permanently. These are two types of memory: RAM, ROM. Random Access Memory(RAM): plays an important role in data processing. The program and data must be loaded into RAM before processing. RAM is also called main memory. It consist memory chips on motherboard. The processor can directly read/write data to and from RAM. More RAM means the computer can use powerful program with large size. RAM is volatile memory, meaning that it loses its contents when computer is shut down. 6

TYPES OF RAM There are 3 types of RAM: (i)DRAM: stands for Dynamic Random Access Memory. It maintain information in DRAM but it must be refreshed with electric charge frequently. Otherwise data in Dram may be lost. (ii) SRAM: stands for Static Random Access Memory. It is faster more reliable than Dram. It does not have to be refreshed electrical charge frequently. (iii) MRAM: stands for Magneto-resistive Random Access Memory. It store information using magnetic charges instead of electric charges. It does not lose its contents (data & instructions) when computer is turned off. 7

ROM Read Only Memory(ROM): ROM stands for Read Only Memory. It is internal memory. The data and instructions stored on ROM can only be read. This is the reason why it is called Read Only Memory. Rom is called non-volatile memory. Because its contents can not be lose when the power is turned off. Mostly instructions of ROM written for operating system. when the computer is switched on the instructions of ROM are automatically activated. These instructions of ROM help the booting process of computer. 8

TYPES OF ROM There are three types of ROM: (i)PROM: stands for programmable Read Only memory. PROM is a blank chip on which a programmer can write program or data using special devices. However, once the data is written in PROM chip, it cannot be modified. (ii)EPROM: stands for Erasable Programmable Read Only Memory. EPROM is also a blank chip like PROM, but its contents can be modified by special device and ultraviolet rays. (iii)EEPROM: stands for Electrically Erasable Programmable Read Only Memory. This kind of ROM can be modified with the help of electrical devices. So the store data can be modified easily. 9

INPUT AND OUTPUT DEVICES The I/O devices provide the means of communication between the computer and the user. The input and output devices are the hardware components that allow the user to input data and to receive the processed data. The data and instruction are given to the computer through input devices and output is received through output devices or it is stored permanently on the storage devices. Input devices include, keyboard, mouse, joystick,scanner, camera. Output devices include, Monitor, printer, speaker, fax etc. 10

INPUT DEVICES Keyboard: keyboard is the mostly used input device. It is used to enter data and instruction into a computer. It looks like a typewriter keypad. But computer keyboard has special keys that perform special functions. The button on keyboard are called keys. The keyboard contain keys for all types of keys alphabetic characters, numeric digits, function keys, and special characters. Keyboard used In PC’S have from 101 to 105 keys. 11

KEYBOARD The most popular keyboard layout is QWERTY KEYBOARD. This is because the 1 st six left topmost keys on the top of alphabets are Q, W, E, R, T and Y. The keys of a standard keyboard can be divided into following four parts: i) Alphanumeric keys ii) Modifier keyboard iii) Numeric keys iv) Function keys v) Cursor-Movement keys vi) Special-Purpose Keys 12

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Keyboard keys Alphanumeric keys: The area look like a typewriter’s keys. This area arranged the same way on almost every keyboard. Including letters, numbers, alphanumeric keyboard have four keys that having their specific functions. THE TAB, CAPSLOCK, BACKSPACE and ENTER keys. Modifier keys: The SHIFT, ALT and CTRL keys are called modifier keys. By working which the purpose of keys are changed e.g., while pressing e it is written in small letters but with pressing SHIFT key its output becomes E. modifiers keys are extremely useful because they give all other keys multiple capabilities. 14

Keyboard keys Numeric keys: the numeric keys normally located on the right side of the keyboard. Numeric keypad looks like a calculator keypad, with its digits 0 to 9 and mathematical operators (+, -, *, /) with NUM key. When NUM key is activated then we input the values from this part when it is deactivated then numeric keypad’s perform cursor-movement control and other functions. Function keys: function keys, which are labeled through F1, F2 and so on are usually arranged in a row along top of the keyboard. They allow the users to input command instead of long strings of characters or dialog boxes. Many programs use functions keys with modifier keys. 15