Here is your short essay on Hardware Concepts

Hardware is a term, which refers to the physical components of a computer system (electronic or electrical), which are used for processing data. Such components are classified according to their functional use within a computer system. The term compute including the central processing unit.

The term ‘Computer peripheral’ is used to denote ail types of units that are connected to the Central Processing Unit which includes inputs/output devices and secondary storage devices. The collection of all the peripheral equipments is called the computer configuration. Technological developments have resulted in an increased number of improved components.

Hardware consists of all components inside the computer which includes Microprocessor, I C’s, SMPS(Switch Mode power supply), Floppy drives, hard diskette etc. The other examples of hardware are those which can be seen by human eye without opening the computer for eg, VDU(Visual Display Unit or monitor), keyboard, mouse, printer, floppy disks, etc.

Hardware

Components of Computer

The basic components of a computer are

1. Input Devices

2. Central Processor

3. Output Devices

Organization of Computer

1. Input Devices

Input devices are the devices which are used to input data into computer. These are again classified into two types :

a) Direct Input Devices

b) Indirect Input Devices

Some of the direct input devices are keyboard, joystick, mouse, lightpen, touch screen, scanner, microphone, etc., examples of indirect Input Devices are Floppy Disks, magnetic disk, compact disk etc., Other input devices available are

MICR – Magnetic Ink Character Reader

OMR – Optic Mark Reader

OCR – Optic Character Reader

Barcode Reader

2. Processor

The very important component of a computer is the processor. It is the brain of the computer. Data or the information that is input through the input device is processed here and is referred as Central Processing Unit (CPU). The CPU consists of: –

a. Arithmetic Logic Unit (ALU)

b. Control Unit

c. Primary Memory

The CPU contains high-speed storage areas called Registers. I is based on this that the speed of the CPU is determined. The program counter and the Instruction Register are the most important registers in the CPU.

a) Arithmetic Logic Unit (ALU)

One of the important components of CPU is Arithmetic Logic Unit (here after referred as ALU) where all the computations an performed. The ALU has two units: –

i. Arithmetic Unit

ii. Logic Unit

The ALU has direct access to the processor controller, RAM an* I/O Devices. First, data enters the primary storage or RAM and the transferred to ALU.

b. Control Unit

The main task of the Control Unit is to co-ordinate and also to execute the program instructions. It is the Control Unit that controls the entire activity of the CPU. It accesses the instructions, interprets them and implements the same. It also instructs the input devices when to send data and stop transferring data to storage device.

c. Primary Storage

Primary storage is also referred to as main memory. It is a place where data and instructions are stored. It is the temporary storage in the computer. The unit of measurement is a bit, which is a binary digit. Therefore, data is represented in the form of O’s and l’s.

3. Output Devices

As the name suggests, output devices are the devices that help in viewing the output. Output devices receive the information from the Central Processor Unit.

Some of the common output devices are: –

A) Printers:

The most common output device is a printer. It helps the user to print the data on the paper. Printers can be classified into 2 types :

a) Impact Printers and b) Non – Impact Printers

In Impact Printers, the paper is in contact with the printer head while printing. Some examples of the impact printers are: –

a) Dot Matrix Printer

b) Daisy Wheel Printer

c) Line Printers.

Non – Impact printers print by using electronic means. Some of the non impact printers are

a) Laser Printers

b) Desk jet printers

c) Ink jet printers

d) Thermal printers.

B) Visual Display Units (VDU)

The most common output device is a Visual Display Unit. The combination of keyboard and the VDU is called a terminal.

C) Voice Output

Computers can convert data to vocalized sounds. This is achieved with the help of voice synthesizers.

D) Plotter

Plotter is generally used to produce outputs that contain graphics. They use either a pen or an inkjet approach.

Main Memory

It is that section of the computer where programs and data are stored. It is a temporary location in the computer for storage of data and instructions. Processors read and write information from memory. The unit of measurement is a bit.

4 bits 1 Nibble

8 bits 1 byte

1024 bytes 1 kilobyte (kb)

1024 kb 1 megabyte (mb)

1024 mb 1 gigabyte (gb)

Memory is classified into two types :

1. Random Access Memory (RAM)

2. Read Only Memory (ROM)

3. Cache Memory

1. Random Access Memory (RAM)

The memory that can be read from and written to is random access memory. When the power fails, the contents in RAM are lost. Therefore, it is volatile. Memory is organised in the form of pigeonholes. Either a 0 or a 1 represents it.

2. Read Only Memory (ROM)

The memory that can only be read but cannot be written to is a Read Only Memory. ROM is non – volatile. The programs are written permanently into the memory at the time of manufacture. Memory is not lost, even when the power fails.

There are different types of ROMs available.

1. Programmable Read Only Memory (PROM) – This is one kind of ROM. Programs can be written into ROM even after its manufacture, but once written it C” ‘.not be erased.

2. Erasable and Programmable ROM (EPROM) – PROMs that can be erased and reprogrammed are called EPROM.

3. Electrically Erasable And Programmable ROM (EEPROM) – This type of ROM uses electrical signal to change the bit pattern.

3. Cache Memory

When data and instructions are processed frequently, then they must be stored at a temporary location, which should be high-speed. This high-speed memory is called cache memory. It is built into processor to enhance the processor speed.

Secondary Storage/Memory

The primary memory is volatile and therefore, there is a need to store data and instructions on a permanent basis. Secondary storage provides just that kind of storage facility. Secondary storage are broadly classified as: –

1. Magnetic media

2. Optical media

1. Magnetic media

It makes use of magnetic spots on the disk to store data. They are further classified into

Magnetic Tapes Magnetic Disks

Magnetic Tape is a form of secondary data. It uses magnetic spots to store data. It is very similar to a tape recorder. The different types of magnetic tapes available are: –

i. Reel-to-Reel tapes.

ii. Cassette tapes

iii. Cartridge tapes

The other secondary storage that is most commonly used is a Magnetic Disk, which may be a

i. Floppy disk

ii. Winchester disk

iii. Removable disk

iv. Disk cartridge

i) Floppy disk

The most common of the secondary storage is a floppy disk. It is made of flexible plastic disk, coated with magnetic material. It is easy to carry around. There is an opening provided on the platstic case to facilitate reading and writing of instruction and data. It comes in two sizes, 5 1/4 and 3 1/2 inches. The 31/2 inch diskette can store upto 1,44mb of data.

ii) Winchester Disk

Another form of secondary storage is Winchester disk. It is popularly known as hard disk. It consists of magnetic plates fixed one below the other with a set of read/write head. This is encased in a pack and the whole pack is permanently sealed to protect it from dust and other damages. Today the storage capacity of a hard disk is in terms of Gigabyte.

iii) Removable Disk Pack

Removable disk packs are very flexible as disk packs can be inserted and removed very easily. They are similar to Winchester Disks.

iv) Disk Cartridge

These are small hard disks that are portable. They can be inserted and removed from disk drives.

2. Optical Disk

The various types of optical storage media available are: –

1. CD – ROM Compact Disk Read Only Memory.

2. CD – R Compact Disk Read only.

3. CD -R/W Compact Disk Read and Write