Apps Engine

What is a Computer Network

A computer network is a system in which multiple computers are connected to each other to share information and resources.


Characteristics of a computer network

• Share Resources from one computer to another
• Create files and store them in one computer, access those files from the other computer(s) connected over the network
• Connect a printer, scanner, or a fax machine to one computer within the network and let other computers of the network use the machines available over network.

Following is the list of hardwares required to setup a computer network.

• Network Cables
• Distributors
• Routers
• Internal Network Cards
• External Network Cards

Network Cables

Network cables are used to connect computers. The most commonly used cable is Category 5 cable RJ-45.

Distributors

A computer can be connected to another one via a serial port but if we need to connect many computers to produce a network, this serial connection will not work. The solution is to use a central body to which other computers, printers, scanners etc. can be connected and then this body will manage or distribute network traffic.

Router

A router is a type of device which acts as the central point among computers and other devices that are part of a network. A router is equipped with holes called ports and computers and other devices are connected to a router using network cables. Now-a-days router comes in wireless modes using which computers can be connected without any physical cable.

Network Card

Network card is a necessary component of a computer without which a computer cannot be connected over a network. It is also known as network adapter or Network Interface Card (NIC). Most branded computers have network card per-installed. Network cards are of two types : Internal and External Network Cards.

Internal Network Cards

Motherboard has a slot for internal network card where it is to be inserted. Internal network cards are of two types in which first type uses Peripheral Component Interconnect (PCI) connection while the second type uses Industry Standard Architecture (ISA). Network cables are required to provide network access.

External Network Cards

External network cards come in two flavours : Wireless and USB based. Wireless network card need to be inserted into the motherboard but no network cable is required to connect to network



Universal Serial Bus (USB)

USB card are easy to use and connect via USB port. Computers automatically detect USB card and can install the drivers required to support the USB network card automatically.

---

Available link for download

computer components

All of computers follow a same basic logical structure and perform the following five basic operations for converting raw input into information useful to their users.

Sr.No.	Operation	Description
1	Take Input	The process of entering and instructions into the system
2	Store	Saving and instructions so that they are available for processing as and when required.
3	Processing	Performing arithmetic, and logical operations on in order to convert them into useful information.
4	Output Information	The process of producing useful information or results for the user, such as a printed report or visual display.
5	Control the workflow	Directs the manner and sequence in which all of the above operations are performed.

Input Unit

This unit contains devices with the help of which we enter into . This unit makes link between user and . The translate the information into the form understandable by .

(Central Processing Unit)

is considered as the brain of the . performs all of processing operations. It stores , intermediate results and instructions(program). It controls the operation of all parts of .
itself has following three

• ALU(Arithmetic Logic Unit)
• Unit
• Control Unit

Output Unit

Output unit consists of devices with the help of which we get the information from . This unit is a link between and users. translate the s output into the form understandable by users.

Available link for download

COMPUTER TYPES

Computers can be broadly classified by their speed and computing power.

Sr.No.	Type	Specifications
1	PC (Personal )	It is a single user system having moderately powerful microprocessor
2	WorkStation	It is also a single user system which is similar to personal but have more powerful microprocessor.
3	Mini	It is a multi-user system which is capable of supporting hundreds of users simultaneously.
4	Main Frame	It is a multi-user system which is capable of supporting hundreds of users simultaneously. technology is different from minicomputer.
5	Supercomputer	It is an extremely fast which can execute hundreds of millions of instructions per second.

PC (Personal )

A PC can be defined as a small, relatively inexpensive designed for an individual user. PCs are based on the microprocessor technology that enables manufacturers to put an entire on one chip. Businesses use personal computers for word processing, accounting, desktop publishing, and for running spreadsheet and database management . At home, the most popular use for personal computers is playing games and surfing .
Although personal computers are designed as single-user systems, these systems are normally linked together to form a network. In terms of power, now-a-days High-end models of the Macintosh and PC offer the same computing power and graphics capability as low-end workstations by Sun Microsystems, Hewlett-Packard, and Dell.

Workstation

Workstation is a used for engineering (CAD/CAM), desktop publishing, development, and other such of which require a moderate amount of computing power and relatively high quality graphics capabilities.
Workstations generally come with a large, high-resolution graphics screen, large amount of , inbuilt network support, and a graphical user interface. Most workstations also have a mass storage device such as a disk drive, but a special type of workstation, called a diskless workstation, comes without a disk drive.
Common operating systems for workstations are UNIX and Windows NT. Like PC, Workstations are also single-user computers like PC but are typically linked together to form a local-area network, although they can also be used as stand-alone systems.

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users simultaneously.

Mainframe

Mainframe is very large in size and is an expensive capable of supporting hundreds or even thousands of users simultaneously. Mainframe executes many programs concurrently and supports many simultaneous execution of programs

Supercomputer

Supercomputers are one of the fastest computers currently available. Supercomputers are very expensive and are employed for specialized that require immense amount of mathematical calculations (number crunching). For example, weather forecasting, scientific simulations, (animated) graphics, fluid dynamic calculations, nuclear energy research, electronic design, and analysis of geological (e.g. in petrochemical prospecting).

Available link for download

computer inputs devices

Following are few of the important which are used in a :

• Keyboard
• Mouse
• Joy Stick
• Light pen
• Track Ball
• Scanner
• Graphic Tablet
• Microphone
• Magnetic Ink Card Reader(MICR)
• Optical Character Reader(OCR)
• Bar Code Reader
• Optical Mark Reader(OMR)

Keyboard

Keyboard is the most common and very popular input device which helps in inputting to the . The layout of the keyboard is like that of traditional typewriter, although there are some additional keys provided for performing additional functions.
Keyboards are of two sizes 84 keys or 101/102 keys, but now keyboards with 104 keys or 108 keys are also available for Windows and .
The keys on the keyboard are as follows:

Sr.No	Keys	Description
1	Typing Keys	These keys include the letter keys (A-Z) and digit keys (0-9) which generally give same layout as that of typewriters.
2	Numeric Keypad	It is used to enter numeric or cursor movement. Generally, it consists of a set of 17 keys that are laid out in the same configuration used by most adding machines and calculators.
3	Function Keys	The twelve function keys are present on the keyboard which are arranged in a row at the top of the keyboard. Each function key has unique meaning and is used for some specific purpose.
4	Control keys	These keys provide cursor and screen control. It includes four directional arrow keys. Control keys also include Home, End, Insert, Delete, Page Up, Page Down, Control(Ctrl), Alternate(Alt), Escape(Esc).
5	Special Purpose Keys	Keyboard also contains some special purpose keys such as Enter, Shift, Caps Lock, Num Lock, Space bar, Tab, and Print Screen.

Mouse

Mouse is most popular pointing device. It is a very famous cursor-control device having a small palm size box with a round ball at its base which senses the movement of mouse and sends corresponding signals to when the mouse buttons are pressed.
Generally it has two buttons called left and right button and a wheel is present between the buttons. Mouse can be used to control the position of cursor on screen, but it cannot be used to enter text into the .

Advantages

• Easy to use
• Not very expensive
• Moves the cursor faster than the arrow keys of keyboard.

Joystick

Joystick is also a pointing device which is used to move cursor position on a monitor screen. It is a stick having a spherical ball at its both lower and upper ends. The lower spherical ball moves in a socket. The joystick can be moved in all four directions.
The function of joystick is similar to that of a mouse. It is mainly used in Aided Designing(CAD) and playing games.

Light Pen

Light pen is a pointing device which is similar to a pen. It is used to select a displayed menu item or draw pictures on the monitor screen. It consists of a photocell and an optical system placed in a small tube. When the tip of a light pen is moved over the monitor screen and pen button is pressed, its photocell sensing element detects the screen location and sends the corresponding signal to the .

Track Ball

Track ball is an input device that is mostly used in notebook or laptop , instead of a mouse. This is a ball which is half inserted and by moving fingers on ball, pointer can be moved. Since the whole device is not moved, a track ball requires less space than a mouse. A track ball comes in various shapes like a ball, a button and a square.

Scanner

Scanner is an input device which works more like a photocopy machine. It is used when some information is available on a paper and it is to be transferred to the hard disc of the for further manipulation. Scanner captures images from the source which are then converted into the digital form that can be stored on the disc. These images can be edited before they are printed.

Digitizer

Digitizer is an input device which converts analog information into digital form. Digitizer can convert a signal from the television or camera into a series of numbers that could be stored in a . They can be used by the to create a picture of whatever the camera had been pointed at. Digitizer is also known as Tablet or Graphics Tablet because it converts graphics and pictorial into binary inputs. A graphic tablet as digitizer is used for doing fine works of drawing and image manipulation .

Microphone

Microphone is an input device to input sound that is then stored in digital form. The microphone is used for various like adding sound to a multimedia presentation or for mixing music.

Magnetic Ink Card Reader(MICR)

MICR input device is generally used in banks because of a large number of cheques to be processed every day. The banks code number and cheque number are printed on the cheques with a special type of ink that contains particles of magnetic material that are machine readable. This reading process is called Magnetic Ink Character Recognition (MICR). The main advantages of MICR is that it is fast and less error prone.

Optical Character Reader(OCR)

OCR is an input device used to read a printed text. OCR scans text optically character by character, converts them into a machine readable code and stores the text on the system .

Bar Code Readers

Bar Code Reader is a device used for reading bar coded ( in form of light and dark lines). Bar coded is generally used in labelling goods, numbering the books etc. It may be a hand held scanner or may be embedded in a stationary scanner. Bar Code Reader scans a bar code image, converts it into an alphanumeric value which is then fed to the to which bar code reader is connected.

Optical Mark Reader(OMR)

OMR is a special type of optical scanner used to recognize the type of mark made by pen or pencil. It is used where one out of a few alternatives is to be selected and marked. It is specially used for checking the answer sheets of examinations having multiple choice questions.

Available link for download

COMPUTER APPLICATION ON THIS DAYS

 

Business

A has high speed of calculation, diligence, accuracy, reliability, or versatility which made it an integrated part in all business organisations.
is used in business organisations for:

• Payroll calculations
• Budgeting
• Sales analysis
• Financial forecasting
• Managing employees database
• Maintenance of stocks etc.

Banking

Today banking is almost totally dependent on .
Banks provide following facilities:

• Banks provide online accounting facility, which includes current balances, deposits, overdrafts, interest charges, shares, and trustee records.
• ATM machines are making it even easier for customers to deal with banks.

Insurance

Insurance companies are keeping all records up-to-date with the help of computers. The insurance companies, finance houses and stock broking firms are widely using computers for their concerns.
Insurance companies are maintaining a database of all clients with information showing

• procedure to continue with policies
• starting date of the policies
• next due installment of a policy
• maturity date
• interests due
• survival benefits
• bonus

Education

The has provided a lot of facilities in the education system.

• The provides a tool in the education system known as CBE ( Based Education).
• CBE involves control, delivery, and evaluation of learning.
• The education is rapidly increasing the graph of number of students.
• There are number of methods in which educational institutions can use to educate the students.
• It is used to prepare a database about performance of a student and analysis is carried out on this basis.

Marketing

In marketing, uses of are following:

• Advertising - With computers, advertising professionals create art and graphics, write and revise copy, and print and disseminate ads with the goal of selling more products.
• At Home Shopping - Home shopping has been made possible through use of computerised catalogues that provide access to product information and permit direct entry of orders to be filled by the customers.

Health Care

Computers have become important part in hospitals, labs, and dispensaries. The computers are being used in hospitals to keep the record of patients and medicines. It is also used in scanning and diagnosing different diseases. ECG, EEG, Ultrasounds and CT Scans etc., are also done by computerised machines.
Some major fields of health care in which computers are used are:

• Diagnostic System - Computers are used to collect and identify cause of illness.
• Lab-diagnostic System - All tests can be done and reports are prepared by .
• Patient Monitoring System - These are used to check patients signs for abnormality such as in Cardiac Arrest, ECG etc.
• Pharma Information System - checks Drug-Labels, Expiry dates, harmful drug’s side effects etc.
• Surgery : Nowadays, computers are also used in performing surgery.

Engineering Design

Computers are widely used in Engineering purpose.
One of major areas is CAD ( aided design). That provides creation and modification of images. Some fields are:

• Structural Engineering - Requires stress and strain analysis for design of Ships, Buildings, Budgets, Airplanes etc.
• Industrial Engineering - Computers deal with design, implementation and improvement of integrated systems of people, materials and equipments.
• Architectural Engineering - Computers help in planning towns, designing buildings, determining a range of buildings on a site using both 2D and 3D drawings.

Military

Computers are largely used in defence. Modern tanks, missiles, weapons etc. Military also employs computerised control systems. Some military areas where a has been used are:

• Missile Control
• Military Communication
• Military Operation and Planning
• Smart Weapons

Communication

Communication means to convey a message, an idea, a picture or speech that is received and understood clearly and correctly by the person for whom it is meant for. Some main areas in this category are:

• E-mail
• Chatting
• Usenet
• FTP
• Telnet
• Video-conferencing

Government

Computers play an important role in government. Some major fields in this category are:

• Budgets
• Sales tax department
• Income tax department
• Male/Female ratio
• Computerization of voters lists
• Computerization of driving licensing system
• Computerization of PAN card
• Weather forecasting

Available link for download