computers concepts

Introduction to Computers

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A World of Computers

Computers are everywhere; at work, at home and at school. Many of our daily activities involve the use of computer. While some computers sit on top of a desk or on floor, mobile computers and mobile devices are small enough to carry. Mobile devices, such as many cell phones, often are classified as computers.

Computers are often used for the following purposes:-

1. Communication:-

Computers are a primary means of local and global communication for billion of people. Consumers use computers to correspond with business, employees with other employees and customers, students with classmates and teachers, and family members with other family members. In addition to sending text based messages, people use computers to share pictures, drawings, music, etc.

2. Information:-

Through computers, society has instant access to information from around the globe. All sort of news, weather report, sports score, maps, job listings, airline schedules, telephone directory, and a lot of educational material are available on the internet. We can access million of information through computers from anywhere in the world.

3. At Home:-

At home people use computers for following two major purposes:-

(i) Household Management:-

At Home people use computers to manage schedules, balance checkbooks, pay bills, transfer funds or buy and sell stocks

(ii) Entertainment:-

People Spend hours of leisure time using a computer, they play games, listen to music or radio broadcast, watch videos, read books, retouch photos and plan vacation.

4. At Workplace:-

At workplace, employees use computers to create correspondence such as e-mails messages, memos, and letters; calculate payroll; track inventory; and generate invoices. Some weather forecasting agencies use computers to perform complex mathematical calculations.

5. At School:-


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At School, teachers use computers to assist with classroom instructions. Students complete assignments and conduct research on computers in lab rooms. In some countries students instead of attending a class on campus take the entire classes directly from home using a computer.

6. On the Road:-

On the road, mobile computers assist people to find their way using maps some vehicles include navigation systems that provide direction, call for emergency services, and track the vehicle if stolen.

Computer Literacy

Having a current knowledge and understanding of computers and their uses is known as Computer Literacy, It is also known as Digital Literacy.

As Technology continues to advance, computers are becoming more a part of every day life. So, many people believe that computer literacy is vital to success in today’s world. The requirements that determine computer literacy change as technology changes.

What is a Computer?

Definition of a Computer:-

A computer is an electronic device, operating under the control of instructions stored in its own memory, that can accept data, process the data according to specified rules, produce results, and stores the results for future use.

Data and Information:-

Data:-

Data is a collection of unprocessed items or raw factors.

Information:-

A lot of data when processed, conveys meaning and becomes useful to people is called information.

A Computer System:-

An organized combinations of people, hardware, software, that collect, transform (processes), store, presents, and disseminates (transmits) information to the users is called a Computer System.

Components of Computer System:-

A Computer System consists of following components:-


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1. Hardware2. Software3. People4. Information5. Procedures

1. Hardware:-

A Computer contains many electric, electronic, and mechanical components known as Hardware.

Hardware includes:-

i. Input Devicesii. Output Devicesiii. Processing Devicesiv. A System Unitv. Storage Devicesvi. Communications Devices

i. Input Devices:-

An input device is any hardware component that allows you to enter data and instructions into a computer.

Following are the six of the most widely used input devices:-

Keyboard Mouse Microphone Scanner Digital Camera Web Cam

Keyboard:-

A computer keyboard contains keys that we press to enter data into the computer.

Mouse:-

A mouse is a small handheld device. With the help of a mouse we can control the movement of a small symbol on the screen, called pointer, and make selections from the screen.

Microphone:-


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A microphone allows us to send voice data over to the computer.

Scanner:-

A scanner convert printed material (such as plain text and pictures) into a form that can be used by the computer.

Digital Camera:-

With a digital camera, we can take pictures and then transfer them to the computer.

Web Cam:-

A web cam is a video camera that allows us to create movies and take still pictures electronically.

ii. Output Devices:-

An output device is any hardware component that conveys information to one or more people.

Four Commonly Used Output Devices are:-

Printer Monitor Speaker Portable Media Player

Printer:-

A printer is an output device that produces text and graphics on a physical medium such as paper.

Monitor:-

A monitor displays texts, graphics, and videos on a screen.

Speaker:-

Speakers allow us to hear music, voices and other audio.

Portable Media Player:-

We can transfer audio, video, and digital images from a computer to a portable media player and then listen to the audio, watch the video, or view the image on the media player.

iii. Processing Devices:-


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The Devices that helps in processing input (given data) to result in a specific output (processed data/information).

Examples of the Processing Devices are:-

Central Processing Unit (CPU) Primary Memory

Central Processing Unit (CPU):-

A Central Processing Unit is a chip placed on the Motherboard that processes all the tasks that are done by the computer.

Primary Memory:-

The role of the primary memory in processing is to store the instruction temporarily i.e. only for the time being for which it is used, and then delete them after they have been processed.

iv. System Unit:-

A system unit is a case that contains the electronic components of the computer that are used to process data.

Motherboard:-

The circuitry of the system unit usually is part of or is connected to a circuit board called the motherboard.

Main Components of Motherboard:-

The two main components of a motherboard are:

(i) Processor(ii) Memory

(i) Processor:-

The processor is an electronic component that interprets and carries out the basic instruction that operate the computer.

(ii) Memory:-

Memory consists of electronic components that store instructions waiting to be executed and data needed by those instructions.

There are two types of Memories:-


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Primary Memory Secondary Memory

Primary Memory:-

The type of memory that keeps data/instructions temporarily is called Primary Memory.

Secondary Memory:-

The type of memory that store data and instructions permanently for future use is called Secondary Memory.

v. Storage Devices:-

Storage holds data, instructions, and information for future use.

Examples of storage devices are:-

USB Flash Drive Hard Disk Compact Disks (CDs and DVDs)

USB Flash Drive:-

A USB Flash drive is a storage device that is small and lightweight enough to be transported on a keychain or in a pocket.

An Average USB Flash drive can hold about 2 Billion characters.

Hard Disk:-

Hard Disk is another storage device that is enclosed in an airtight sealed case.

Hard Disks are either portable or non-portable (internally connected) An average hard disk can hold about 320 billion characters.

Compact Discs:-

Compact disks are flat, round shaped, portable metal discs. There are two types to compact discs CDs and DVDs.

A CD can hold about 650 million to 1 Billion characters. A DVD can hold about 17 Billion characters.

vi. Communication Devices:-

A communication Device is a hardware that enables a computer to send and receive data, instruction, and information to and from one or more computers.


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Most commonly used communication devices are:-

Modem Cables

Modem:-

Modem is a widely used and most common communication device that coverts digital signal to analogue and analogue signal to digital.

Cables:-

Cables are the communication devices through which data passes in form of electric or light (in case of optical fibers) signals.

2. Software:-

Computer software, also called program, consists of a series of instructions that tells the computer what to do and how to do it.

User Interface (UI):-

The user interface determines how we enter data and how information is displayed the screen. We interact with the software using it user interface.

Graphical User Interface (GUI):-

In graphical user interface we interact with the software using text, graphics, and visual images such as icons.

Icon: An icon is a miniature image that represents a program, an instruction, or some other object.

Types of Software:-

There are two categories of software:-

1. System Software2. Application Software

1. System Software:-

System Software consists of the programs that control or maintain the operation of the computer and its devices.

System software servers as the interface between the user, the application software, and the computer’s hardware.

There are two types of System Software:-

(i) Operating System


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(ii) Utility Software

(i) Operating System:-

An operating system is a set of programs that coordinates all the activities among computer hardware devices.

It provides a means for users to communicate with the computer and other software. Examples of operating systems are Windows XP, Windows Vista (two of Microsoft’s

operating systems), or Mac OS X (Apple’s operating system).

(ii) Utility Software:-

A utility program allows a user to perform maintenance-type tasks usually related to managing a computer, its devices, or its programs.

For example, we can use a utility program to transfer digital photos to a CD or DVD. Most operating systems include several utility programs for managing disk drives,

printers, and other devices and media.

2. Application Software:-

Application Software consists of programs designed to make users more productive and/or assist them with personal tasks.

Web Browser is widely used application software that allows users to access web pages.

Other popular application software includes word processing software, spreadsheet software, database software, and presentation graphic software.

3. People

People (from the prospective of computer system) are those human beings that are directly and/or indirectly involved in the usage of computer and computer applications.

People can be in general said to be Users.

There are five major categories of Peoples/Users:-

1. Home Users2. Small Office/Home Office Users3. Mobile Users4. Large Business Users5. Power Users

1. Home Users:-

Home users use computer for different purposes that includes budgeting and personal finance management, Web access, communications, and entertainment.


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Home Users usually use a Desktop Computer

2. Small Office/Home Office Users:-

Small Office/Home Office users include any company with fewer than 50 employees, as well as the self-employed who work for home.

Small Office includes local law practices, accounting firms, travel agencies, and florists.

Small Office Users usually use a Desktop Computer or even a small network of computers consisted on a few computers.

3. Mobile Users:-

Mobile Users are the ones that work on a computer while away from home.

Mobile Users usually use Notebook Computer, Tablet PC; Internet enabled PDA, Laptop Computer, or a Smart Phone.

Examples of mobile users are sale representatives, real estate agents, insurance agents, meter readers, journalists, consultants, students.

4. Power Users:-

Power Users are the technical people who use powerful computers.

Examples of Power Users include engineers, scientists, architects, desktop publishers, and graphic publishers.

Power User use industrial-type Software. Power Users use Super-Computers, Main-Frame Computers or Servers.

5. Large Business Computers:-

A large business has a hundreds or thousands of employee or customers that work in or do business with offices across a region, the country, or the world. Each employee or customer who uses a computer in the large business is a large business user.

Enterprise Computing: Many large business companies use the words, Enterprise Computing, to refer to the huge network of computers that meet their divers computing needs.

Large Business Users use Servers or Mainframe Computers.

4. Information:-

The Processed form of data is known as information

Information can be in the form of either of the following:-


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Text Audio Video Graphics Animations

Text:-

The information stored inform of words is called text.

GENERAL FORMATS: TXT, DOC.

Audio:-

Audio includes music, speech, or any other sound.

GENERAL FORMATS: MP3, WMV, RA, AAC, AIFF, ASF, WAV, QT.

Video:-

Video consists of full-motion images that are played back at various speeds.

GENERAL FORMATS: WMV, MPEG-4, AVI, RM.

Graphics:-

A Graphic, or graphical image is a digital representation of non-text information such as drawing chart or photo

GENERAL FORMATS: BMP, JPEG, PNG, TIFF.

Animations:-

One or more still images are combined and played in such a way that they seem to be moving form an Animation.

GENERAL FORMAT: GIF.

5. Procedures:-

The rules, regulation, guidelines, that run a computer system are known as Procedures.

Following are the three basic types of procedures:-

Operational Procedures Backup Procedures Security Procedures

Operational Procedures:-


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Operational Procedures are used to run the system.

Backup Procedures:-

Backup Procedures are used to restore the system if the system crashes down.

Security Procedures:-

Security Procedures are used to prevent the computers from an outside attack.

Categories of Computers

Following are the main categories of Computers:-

1. Personal Computers2. Mobile Devices/Mobile Computers3. Mainframes4. Super-Computers

1. Personal Computers:-

A Personal Computer is a Computer that can perform all of its input, processing, output, and storage activities by itself.

A Personal Computer is designed specially for the use of a single person. Two Popular styles of personal computers are the PC (which refers to any computer

based on the IBM Personal Computer design.) and the Apple (which refers to the Apple Macintosh Personal Computer.

There are two types of personal computers:-

(i) Desktop Computer(ii) Notebook Computer

(i) Desktop Computer:-

A Desktop Computer is the one that is designed such that the system unit, input devices, output devices, and any other devices fit entirely on or under the table or a desk.

(ii) Notebook Computer:-

A Notebook Computer is a portable computer that contains all the features of a desktop computer.

Two of the most common example of


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Laptop Tablet PC

Laptop Computer:-

A Laptop Computer is specially designed computer that can fit on a user’s lap.

Tablet PC:-

A Tablet PC is a special type of Notebook Computer that allows users to write or to draw on the screen using a digital pen.

2. Mobile Computer:-

Mobile Computers are designed such that they can be carried anywhere by the user.

Mobile Computers are designed for travelling people.

Three Popular Types of Mobile Computers are:-

(i) Handheld Computer(ii) PDA (Personal Digital Assistant)(iii) Smartphone

(i) Handheld Computer:-

A Handheld Computer is designed such that it fits in one’s hand and be carried in one’s pocket.

Ultra Mobile PCs: Handheld Computers are sometimes referred to Ultra Mobile PCs. Many Handheld Computers communicate with other devices wirelessly.

(ii) PDA (Personal Digital Assistant):-

A PDA is a hand held device that provides personal organized functions such as a calendar, an appointment book, an address book, a calculator, and a notepad.

(iii) Smart Phone:-

A Smart Phone is an internet enabled phone that usually provides PDA capabilities.

Smart Phone provides convenience one-handed operation.

3. Servers:-

A server controls access to the hardware, software, and other resources on a network and provides a centralized storage area for programs, data, and information.

Servers can support from two to several thousand computers connected at the same time.


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4. Mainframes:-

A mainframe is a large, expensive, powerful computer that can hold thousands of connected users simultaneously.

Mainframes can also act as servers in some networks. Most major corporations use mainframes for business activities. Mainframes store tremendous amount of data.

5. Super Computers:-

A Super Computer is the fastest, most powerful computer – and the most expensive.

Super Computer is capable of processing more than 135 trillion instruction in a second

Weight of a Super Computer exceeds 100 tons Super Computers are used when complex mathematical calculations are required Super Computers are usually use in medicine, aerospace, automotive design, online

banking, weather forecasting, and nuclear energy power plant.

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