Sponsored Links

Wednesday, August 31, 2011

Types Of Data

Leave a Comment

DATA

Data is the collection of raw facts and figures. It is without any proper meaning.
Data may be collection of words, numbers, graphics or sounds.
Examples of Data

1) Student Data on Admission Forms

When students get admission in a college. They fill admission form. This form     contains raw facts (data of student) like name, father’s name, address of student etc.

2)    Data of Citizens

During census, data of all citizens is collected.

3)    Survey Data

Different companies collect data by survey to know the opinion of people about their product.

4)    Students Examination data

In examination data about obtained marks of different subjects for all students is collected.   

Types Of Data

There are following main types of Data.

1)    NUMERIC DATA




Numeric data consists of 0 to 9 digits, + and – sign and decimal point etc.
For example, 10, 78, 90.50, -56 etc

2)    ALPHABETIC DATA

It consists of all alphabetic letters A to Z, a to z and blank space etc. For example, Pakistan, Ahmad, Abdul Rahim, GCC , RYK, Ahmad etc.

3)    ALPHANUMERIC DATA

It consists of alphabet letters, digits and special characters like #, $, % etc.
For example, House Number 10-A, 14-August-1947, F-16 etc.
   

4)   GRAPHIC DATA   

Graphic data or image data consists of charts, graphs and images etc. For example a collection of maps of countries, a collection of family pictures etc.

5)    AUDIO DATA

Audio data consists of sounds and voices. For example audio naat, radio program, radio news, audio songs etc.

6)    VIDEO DATA

Video data consists of moving pictures. For example movie, TV dram, TV news etc.

7)    MIXED DATA

Mixed data consists of combined data of two or more types. For example, TV drama consists of audio as well as video data.   
Read More...

Thursday, August 25, 2011

Explain Data Processing Cycle

1 comment
After collecting data, it is processed to convert into information. The data is processed again and again until accurate result is achieved. This is called data processing cycle.
Data processing cycle involves following three basic activities:

1. Input

2. Processing

3. Output

1. INPUT

It is the process in which collected data is given to computer after converting into binary form. Input step can be further divided into following steps:
i) Planning
Here objectives of data processing are defined. For example, in examination system, objective is to process student examination data to get result cards.
ii) Data Collecting
Here data is collected. Data is the raw material for data processing. This must be accurate for getting accurate results.
iii) Input
Here data is entered into computer.
iv) Verification
Here collected data is verified to determine whether it is valid for processing. For example marks must be in numeric form.
v) Coding
Data is stored in computer in binary form. Here data is converted (or coded) into computer readable (binary) form.

2. PROCESSING

Now data is ready for processing. We process collected data to convert into information. Some important activities in processing are as following:
i) Data Classification
Here data is classified into different groups or sub-groups. So that it can be handled easily and separately. For example if we collect data about students of a college we will divide them into D.Com and B.Com class groups.
ii) Data Sorting
Here data is arranged in some order. So that it can be accessed quickly. For example we can sort student data by Roll number or name.
iii) Data Calculation/Processing
Here arithmetic and logical operations are performed on data to get the required result. For example total marks of each student are calculated.

3. OUTPUT

After completing the processing, output is received. Output step involves following steps:
i) Testing
The results are tested to find if they are according to requirements. And any errors are removed. If results are not satisfactory then we repeat above-mentioned steps again and again until the accurate results are found.
ii) Summarizing
Huge results are summarized to make them short and precise.
iii) Storing results
The results are stored properly on secondary storage devices for future use.
iv) Output the result
Here output is produced as softcopy on screen or as hard copy as printout. Information is sent to different places as needed.
v) Feed Back
In this step we take comments from users about output results. If results are not satisfactory then we repeat above-mentioned steps again and again until the accurate results are found.
Read More...

Differences Between Data and Information

Leave a Comment
Here we are going to discuss the differences between two typical terms of information technology: Data and Information. Data is a collection of raw facts and figures about an entity. Data may consist of numbers, characters, audio, video or pictures etc. When these data is processed according to requirements, then it is transformed into INFORMATION.

For example, consider Admission system of a Computer College. The candidates will submit admissions forms filled by them. Now all the facts and figures and picture of candidate on form is called data. These data may consist of name, father's name, date of birth, marks obtained, total marks, address, contact number and a latest photo graph of the candidate.
Now the concerned person in the college office will process these data to prepare a merit list. He may calculate percentage of obtained marks of each candidate and arrange the records in descending order by percentage. This merit list is an example of Information. Information is useful in decision making. The merit list will declare the names of students who will have a right to get admission in the college.
Example of Data
Example of Information

 


            DATA


       INFORMATION


1


Data is collection of
raw facts and figures.


Information is
processed data.


2


Data is unarranged and
unorganized..


Information is arranged
and organized..


3

Data
is un-meaningful.
Information
is meaningful.

4




Data is input.



Information is out put.

5




Data is used less frequently.



Information is used frequently.

6


Data represents facts
before processing.


Information represents
results (obtained after processing).


7


Data is not helpful in
decision-making.


Information is helpful
in decision-making.


8


Data is raw material
for information.


Information is the
final product of data.


9


Data are unprocessed
records


Information contains
processed records


10


Data is in large
amounts


Information is in small
amounts


11


If data is lost, it is
very difficult (or even impossible in some situations) to re collect.


If information is lost,
it is easily derived from stored data, again.


12


Data is collected by
observations, recordings, interview or survey etc. For example, if we
record the temperature of each hour recorded in a particular day is called
temperature data.


Now we will process
these temperatures data to find useful information. For example if we
arrange temperatures in ascending order, then we will find the information
like:

Minimum Temperature of
the day= 15 C  and Maximum
Temperature of the day = 25 C.


13


Data is the asset of an
organization and is not available for sale to public.


Normally, information
is available for sale to general public.


14

Data depends upon the sources for collecting data, the collection methods
adopted and the people who will collect data.
Information depends upon data.

Read More...

Wednesday, August 24, 2011

Define Data and Information With Examples

1 comment
DATA

Data is the collection of raw facts and figures. It is without any proper meaning.
Data may be collection of words, numbers, graphics or sounds.
Examples of Data

1) Student Data on Admission Forms
When students get admission in a college. They fill admission form. This form     contains raw facts (data of student) like name, father’s name, address of student etc.

2)    Data of Citizens
During census, data of all citizens is collected.

3)    Survey Data
Different companies collect data by survey to know the opinion of people about their product.

4)    Students Examination data
In examination data about obtained marks of different subjects for all students is collected.   


INFORMATION
    Processed data is called information. When raw facts and figures are processed and arranged in some order then they become information. Information has proper meanings. Information is useful in decision-making. Actually we process data to convert it into information. Here are some clear easy to understand differences between data and information.
Examples of Information:

1)    Student Address Labels
Stored data of students can be used to print address labels of students.

2)    Census Report (Total population, Literacy Rate, Male / Female ratio etc.)
Census data is used to get report/information about total population of a country and literacy rate etc.

3)    Survey Reports and Results
Survey data is summarized into reports/information to present to management of the company.

4)    Result Cards of Individual Students, Result sheets of  a particular Class
In examination system collected data (obtained marks in each subject) is processed to get total obtained marks of a student. Total obtained marks are Information. It is also used to prepare result card of a student.
5)  Merit List
After collecting admission forms from candidates, merit is calculated on the basis of obtained marks of each candidate. Normally, percentage of marks obtained is calculated for each candidate. Now all the candidates names are arranged in descending order by percentage. This makes a merit list. Merit list is used to decide whether a candidate will get admission in the college or not.

Further related Topics to study:

Read More...

Tuesday, August 23, 2011

Explain Different Types of Software

2 comments

Types of Software


The main types of software are system software and application software.
1. System Software
System software is a set of programs to implement certain functions in a computer system. It controls the overall operations and components of a computer system.
It is the base on which application programs are executed. It is an interface between user and computer. Operating systems like Windows, Linux and Unix are the main example of system software. Similarly device drivers software are also examples of system software.
Examples of system software are as follows:

•   Operating Systems

Operating system is software to control overall operations and components of a computer system. e.g., Windows, UNIX, Linux and Dos etc.

•   Utility Programs

Utility program is used to solve a particular problem of software or hardware, for example, Antivirus program, disk scanner and File Viewer etc.

•   Device Drivers

Device driver is software that permits a computer system to communicate with a device. e.g., device driver software for a modem comes with it on CD. We have to install device driver before using a device.

•   Language Processors

Language processor is software that converts a source program into object program. For example C- compiler converts a program written in C language into object program (machine code).
2. Application Software
Application software is a program needed to perform various applications on the computer by the user. It helps a computer user to solve specific problems like to prepare letters and other documents, to create pictures and advertisements, to perform large calculations quickly etc.
The application software runs on top of the operating system software.
Examples of application software are as follows:

i. Word Processing

Word processing software is used to produce letters, applications and other documents. Microsoft Word is the most popular application software used for word processing.

ii. Spreadsheets

Spreadsheet program is used to create electronic worksheets. These worksheets are used to perform calculations on large amounts of data quickly and automatically. Microsoft Excel is a popular spreadsheet program.

iii. Databases

Database software is used to record data of an organization on computer in compact and efficient form. MS Access, MS SQL Server and Oracle are examples of database software.

iv. Graphics

Graphics software is used to produce advertisements, posters and pictures etc. for example CorelDraw and Photoshop are popular graphics software.

v. Communication

Communications software is used to communicate with different people using Internet, e.g., MSN Messenger, yahoo messenger and Internet Explorer.
Read More...

Saturday, August 20, 2011

Explain Computer Software With Examples

1 comment
Software
Software is a set of instructions that tell a computer what to do. Software is the set of instructions given to computer to perform a task or to control operations of computer. Software cannot be touched. The hardware cannot perform any task without software. Software is installed on hard disk. When we use any software it is loaded into RAM from hard disk.
Examples of software are:
  1. MS Word
  2. MS EXCEL
  3. MS POWER POINT, 
  4. WinZip
  5. Norton Anti Virus
  6. MSN Messenger 
  7. and MS Windows etc. 
          
Microsoft WORD:
MS Word

This software is used to prepare letters, applications, office documents and all types of documents and books etc.
Microsoft Excel:
MS Excel





It is used calculations and preparing electronic worksheets for example creating Employees Pay Sheet or Students Result Sheet.
         
MS POWER POINT:





It is used to prepare presentations to be presented on multimedia projectors.
WinZip:

This software is used to store a file as compactly as possible, in the minimum file size possible. WinZip makes easy to take files from one computer to another and stores them in less storage space. When we need to use the zipped file, we have to unzip it or extract it to the original state and size.
Norton Anti Virus:

This software is used to detect and remove virus attacks on your computer.

MSN Messenger:

It is used for online chatting with friends all over the world.
MS Windows:  




Microsoft Windows is the most popular Operating system in the world. First of all, you have to install an operating system on computer, before it will be ready for work. After installing the operating system like Microsoft Windows, now you can install application software like MS Excel, MS Word or games etc. In short, without an operating system you cannot use a computer.

Read More...

Tuesday, August 9, 2011

Different Types of Mouse Input Device

1 comment
A mouse is a small, lightweight pointing input device. Mouse is moved on a flat surface to control the movement of the pointer on a screen. A mouse usually has two or three buttons. These buttons are used to perform different tasks.
Different types of mouse are as follows:
  • Mechanical Mouse





Mechanical mouse contains a rubber or metal ball inside it. The movement of the cursor depends on the movement of the ball.



This mouse is normally used on mouse pad. Mouse pad is a- small flat pad made of rubber or foam to provide easy movement for the mouse. It protects the mouse from dust and dirt.
  • Optical Mouse



Optical mouse contains no ball inside it. It uses a device that emits light to detect the mouse movement. Optical sensor or laser is used in these types of mouse. It is more expensive than mechanical mouse.
  • Wireless Mouse


Wireless or cordless mouse is a type of mouse that does not require a wire to work. It transmits data using wireless technology like radio waves or infrared light waves. The receiver is connected to the computer through a serial or USB port.
Read More...

What are Pointing Input Devices

1 comment
 A Pointing input device is an input device which is used to control  the movement of the pointer to select items on a display screen. Examples of pointing devices

include: Mouse, Track ball, Joystick, Pointing Stick, Graphic Tablet, Touch pad or Track pad, Touch Screen and Light pen etc.

1. Mouse

Mouse is an input device used to control motion of pointer on screen. A mouse has two or three buttons called Left, Right and Middle button. Buttons are used to perform different functions.

2. Track Ball

 
Track Ball is an input device like a mouse. It is used in Lap top computers to control motion of pointer on screen. It is a pointing device like upside down mouse. It has a ball on its upper side. This ball is moved by fingers or thumb and the pointer moves accordingly on screen.

3. Joystick
 
Joystick is an input device used to play games on computer.

4. Pointing Stick

A pointing stick is a pressure sensitive small nub ( similar to pencil eraser ) used like a joystick. It is usually found on laptops fixed between the 'G', 'H', and 'B' keys. It operates by sensing the pushing force applied by the user. The pointer on the screen moves, when user pushes pointing stick with finger. Normally, it is
used with laptop computers.

5. Graphic Tablet

 A graphics tablet consists of a special pen called stylus and a flat pad. The image is created on the monitor screen as the user draws it on the pad with the help of stylus (special pen).

6. Touch Pad or Track Pad
 
Touch pad or Track pad is a pointing input device. It is used in Lap top computers to control motion of pointer on screen. Track pad is a stationary input device. It has a flat surface of 1.5 to 2 square inch. Finger is moved on this surface to move pointer on screen.

7. Touch Screen

 In ATM and in latest smart phones, touch screen is used to receive input from the user. The user enters data by the touch of his finger on different menu options or icons present on touch screen.
 
8. Light Pen


Light pen is an input device consisting of a special pen that is connected to a computer's monitor. The user points at the screen with the pen and selects items or chooses commands.

Read more  Different Types of Input Devices
Read More...

Saturday, August 6, 2011

Explain different types of storage devices

1 comment
Storage Devices

Storage devices are used to store data and instructions permanently. Storage devices are also called secondary storage devices / backing storage devices / external storage devices or auxiliary storage devices. Examples of storage devices include Hard Disk, CD and DVD etc.

Why Secondary Storage Devices are Used?

Secondary storage devices are used because:
  1. Primary memory(RAM) is volatile and temporary. When computer is switched off, all data in ram is erased.
  2. Storage devices can store large amounts of data and instructions permanently whereas Primary memory has less capacity of storing data.
Types Of Storage Devices

There are three main types of storage devices:

1. Magnetic Tape 2. Magnetic Disk 3. Optical Disk

1. Magnetic Tape



Magnetic tape is the oldest storage device. It is made of plastic coated with magnetic material. Data is stored on magnetic tape in the form of magnetic spots. Tape drive is used to read and write data on tape. Magnetic disk is sequential access device. It is slower device than magnetic disk or optical disk. Magnetic tapes are used in reels of different lengths, for example 200, 600, 1200 feet etc.

2. Magnetic Disk

A magnetic disk is a thin circular metal or plastic disk coated with magnetic material. Data is stored in the form of magnetic spots. Magnetic disk is random access device. It is faster than magnetic tape. There are three main types of magnetic disk:
a. Hard Disk b. Floppy Disk c. Zip Disk


a. Hard Disk

The hard disk is also called fixed disk. It consists of one or more metal plates. The plates are fixed in the drive. Metal plates are coated with magnetic material to store data. A motor rotates disks. There is also an access arm and read / write heads to read and write data on disks.
Following are major characteristics of hard disk:
- The storage capacity of hard disk is much greater than floppy disk.
- Now a days hard disks of size 40 GB, 80 GB or more are available.
- Hard disk is covered in a hard jacket and there are less chances of disk damage due to dust and mishandling.
- Now days Operating system and application programs are installed on hard disk.
- Before using a magnetic disk we use operating system to format the disk. Operating system divides the disk into circles called tracks. Each track is divided into pie-shaped areas called sectors. Data is stored in sectors. Each sector can store 512 bytes.

b. Floppy Disk

Floppy disk is a small plastic plate coated with magnetic material. Data is stored in magnetic spots. Main advantage of floppy disk is that it is used to transfer data from one computer to another. Floppy disk drive is used to read and write data on floppy disk.
Floppy disk is available in two sizes:
· 3 ½ INCH Floppy Disk
It is also called micro floppy disk. Its diameter is 3½ inch. It is covered in a hard plastic cover. Read/Write window is covered with a metal shutter. When disk is inserted into disk drive then shutter is automatically opened. It can be write protected by a notch. Storage capacity of micro floppy is 1.44 MB.
· 5¼ Inch floppy disk.
It is a 5¼ inch diameter plastic plate coated with magnetic material. Its storage capacity is 1.2 MB. It is not used in modern computers.

c. Zip Disk

Zip disk is similar to 3 ½ inch floppy disk. But it can store 100 MB or more data. Zip disk drive is used to read and write data on a zip disk.

3. Optical Disk

LASER technology is used to read and write data on Optical disk. LASER stands for Light Amplification through Emission of Radiation. Laser beam writes on the surface of optical disk by creating very small holes. The presence of hole represents a One and absence of the hole represents a Zero. There are following main types of optical disk.
1.CD-ROM, 2. CD-R or WORM, 3. CD-RW
4.DVD-ROM, 5. DVD-R, 6. DVD-RW

 1. CD-ROM



CD-ROM stands for Compact Disk-Read Only Memory. The data stored on Cd-Rom can only be read. It cannot be deleted or changed. It is a portable storage device. Data can be easily transferred by CD Rom from one computer to another. Commonly it can store 650 MB / 700 MB/ 750 MB data. It is used to store large amounts of data like Software or audio/video data.We purchase Software, movies, dramas, lectures, books, wallpapers and other data on Cd-Rom. There are many Advantages of Compact Disk.

2. CD-R (CD Recordable) Or WORM (Write Once Read Many)

CD-R stands for Compact Disk -Recordable. Initially, it is a blank disk. User can store data on it only once. This is why it is also called WORM(Write Once Read Many) disk too. Because we can write data on it only once and later we can read many times. The devices to store data on CD-R are called CD Writers or CD Burners. We can write data on CD-R only once, but can read data many times. Because of this write once read many quality, CD-R is often known as WORM(write once read many).

3. CD-RW ( CD Rewritable )

CD-RW stands for Compact Disk Rewritable. This is a special type of CD. User can write data on it, if there is an error in writing data, he may erase the contents and rewrite again. CD-Writers are used to store data on CD-RW.

4. DVD - Digital Video Disk (DVD-ROM)

DVD stands for Digital Video Disk. A laser beam with a short wave length is used to create very very small holes on the surface of disk. So there are much more tiny holes on the surface of DVD as compared to that of CD. Therefore, storage capacity of DVD is much larger than CD. It can store up to 17 GB or more data. DVD-ROM is pre recorded and it can contain data like movies, videos and software etc. User cannot change or delete data from DVD-ROM. It is read only. There are several Benefits of using Digital Video Disk or DVD.

5. DVD-R (DVD-Recordable)

DVD-R stands for Digital Video Disk Recordable. Initially it is a blank disk. User can store data on disk only once. Then it becomes read only. It is normally used to store high definition video movies. DVD-Writers are used to store data on DVD-R.

6. DVD-RW ( DVD Rewritable)

DVD-RW stands for Digital Video Disk Rewritable. User can write data on disk many times by erasing the old data.

Here are some Differences Between CD and DVD.
Read More...

Thursday, August 4, 2011

Discuss Differences Between RAM and ROM

Leave a Comment
We have already discussed the topics:
1. What is RAM, Explain Different Types of RAM
2. What is ROM Explain Different Types of ROM
Here we discuss differences between RAM and ROM

Sr # RAM ROM
1 RAM stands for Random Access Memory ROM stands for Read Only Memory.
2 RAM is a temporary memory. ROM is a permanent memory.
3 RAM is a volatile memory. ROM is a non volatile memory.
4 When computer is turned off, all data and programs are
erased from RAM. 
When computer is turned off, all data and programs are
retained in ROM.
5 RAM is a Read / Write memory. Data can be read and written
to RAM.
ROM is a read only memory. Data from ROM only can be read
and not written.
6 Data and programs in RAM can be changed. The contents of ROM cannot be changed.
7 Data or programs in RAM can be deleted. Contents of ROM cannot be deleted.
8 The instructions and data  are written (loaded) in RAM
at execution time, when computer is working.
The instructions in ROM are written at the time of
manufacturing.
9 RAM is used to load data and programs currently running. ROM contains the instructions that help the computer to
start-up and make it ready for work.
10 RAM is much faster than ROM. ROM is slower than RAM.
11 RAM has two main types: Static RAM and Dynamic RAM ROM has three types: PROM, EPROM and EEPROM
12 Physically RAM chip is larger than ROM chip. Physically ROM chip is smaller than RAM chip.
13 Picture of RAM is:
RAM
Picture of ROM is:
ROM

You may also like:
Read More...

Wednesday, August 3, 2011

What is ROM Explain Different Types of ROM

Leave a Comment

ROM


ROM stands for Read Only Memory, because its contents can be read and used only and we cannot change or delete its contents. It is a non volatile memory. Its retains its contents even after switching off the computer. Therefore, ROM does not require electricity to retain its contents. ROM is a permanent memory. The instructions in ROM are written at the time of manufacturing by the manufacturer.  

Importance of ROM


1. One important reason a computer needs ROM is that instructions stored in ROM (called ROM BIOS - Basic Input/Output System)execute on start-up of computer and guide the computer what to do. They make the computer ready for work.
2. ROM contains a set of start-up instructions to check that memory is functioning well and check for other hardware devices.
3. These instructions also check for an operating system and load its necessary part into RAM, so that a user interface for example "Windows Desktop" is displayed on computer screen. Now computer is ready to work with. A user now can easily perform work on computer.

Where ROM Chip is installed?


ROM chip is fixed on motherboard as shown in the figure: AMIBIOS -American Megatrends ROM chip.
Picture of ROM fixed on mainboard
Another picture of Rom



Types of ROM


Following are the types of ROM

  • PROM

PROM stands for Programmable Read Only Memory. Instructions can be stored in PROM only once. Then it becomes ROM and we cannot change instructions in it. Initially PROM is a blank chip. Once instructions are written on it, then it become ROM. Now we cannot change or delete the instructions. If there is any error in writing instructions then PROM chip becomes unusable.
  • EPROM

EPROM stands for Erasable Programmable Read Only Memory. Program instructions written on EPROM can be erased and changed with the help of ultra violet rays. So if once we write instruction on this chip with errors, we can erase wrong instructions and rewrite new instructions.
  • EEPROM

EPROM stands for Electrically Erasable Programmable Read Only Memory. Program instructions written on EEPROM can be erased with the help of electricity and rewritten.
Read More...

What is RAM, Explain Different Types of RAM

Leave a Comment
RAM

Ram stands for random Access Memory. Data in RAM can be accessed directly. That is, we can access data directly from any location of RAM in the same time. This Random Access quality makes RAM a very fast memory. RAM is volatile. Data and programs in RAM are erased when computer is turned off. Therefore RAM is a temporary memory. It is used to store those data and programs, which are currently being executed by CPU. Ram is also called Primary Memory or Main Memory.

Where RAM memory chip is installed?

RAM chip is installed into one of the memory slots on motherboard, as shown in the figure:


Importance of RAM.

1.  A Program must be laoded in RAM for execution.
The programs and data currently being executed are in computer's main memory, that is, in RAM. The programs and data needed by these programs is loaded into RAM and run from this memory for FAST ACCESS. Because hard disk is very slow device, every program we run, is loaded into RAM from hard disk first, and then it is executed by processor. CPU is very fast device, it can take instructions and data to execute from RAM much faster than from a hard disk. 


2. RAM is an  Important Factor in increasing Speed of Computer

One of the most important factors affecting the speed and power of a computer is the AMOUNT OF RAM it has. Normally, the more RAM a computer has, the more speed and power of working it has.In fact,  if a computer with a very fast processor has inadequate amount of RAM, it may still run slowly, especially when running multiple programs.

Types of Ram

There are two main types of Ram.
  • Dynamic Ram (DRAM)
Dynamic Ram is widely used in personal computers. It is a cheaper kind of RAM. DRAM loses electric charge with the passage of time, so DRAM needs to be refreshed frequently. Otherwise, it may lose data. Dram is recharged many times in a second. Therefore, it is slower than SRAM. Since CPU cannot access the data from DRAM while it is in the process of refreshing or recharging.
  • Static Ram (SRAM)
Static Ram does not need to be refreshed again and again. So processor can access data from static RAM faster than DRAM. There is no time wastage in refreshing the memory again and again. Static RAM is more expensive and faster than DRAM. Static Ram is used to build a very fast memory called CACHE (pronounces 'cash' ) memory.
Read More...

Monday, August 1, 2011

What are Dual Devices or Both Input/ Output Devices

1 comment
The devices that can be used to perform both functions -input and output- are called Dual Devices. These devices are also called Dual Purpose Devices or Both Input/Output Devices. With the help of a dual purpose device, we can enter data into computer as well as we can output data from the computer to outside world.  For example, Dual devices include:  Touch Screen Monitor, Modem, Network Interface Card, Sound card, Hard disk drive, Floppy disk Drive, Magnetic Tape Drive CD-Writer and DVD-Writer etc. These are also called Input/output devices, because they perform both functions.
  • Touch Screen Monitor

Touch Screen Monitor is an input/output device. It uses a special touch sensitive screen. The User can enter data by touching icons or menus on the screen. As soon as the user selects a command from menu, output is displayed on screen. Commonly touch screen monitors use sensors to detect touch of finger.
  • Modem
Internal modem

External modem

Modem stands for Modulator / Demodulator. Modem is a communication device.  It performs two functions: Modulation (converting digital signal into digital signal) and Demodulation(converting analog signal to digital signal). It makes possible receiving data from internet into our computer (input) and sending data from our computer to another computer on internet(output). Modem sends and receives data from one computer to another through telephone lines. It links your personal computer to the Internet through your ISP (Internet Service Provider). A telephone line supports only analog signals, whereas computer accepts only digital signals. So when a computer wants to send data to another computer, digital data is converted into analog data before placing on telephone line. The process of converting digital signal into analog signal is called Modulation. Similarly, on the receiving computer, modem converts analog data (from telephone line) into digital data, before it is entered into receiving computer. The process of converting analog signal into digital signal is called Demodulation.  
  • NIC - Network Interface Card
NIC or LAN card

NIC stands for Network Interface Card. It is used to link network computers for transmitting data. With the help of NIC our computer can receive  data, instructions and information from another computer (input). NIC will also be helpful to send data from our computer to another computer on the network (output). NIC is also called a LAN card, local area network card or LAN adapter.


  • Sound Card
Sound card or audio card

A sound card is a computer component that facilitates the input and output of audio signals to and from a computer. A speaker produces audio output with the help of sound card. In addition we use microphone to input our voice into computer with the help of sound card. 
  •     Hard disk Drive

Hard disk drive is an input/output device. It has read/write heads to read data from hard disk(input) and to write data to hard disk(output).
  • Floppy disk Drive

Floppy disk drive is an input/output device. It has read/write heads to read data from floppy disk(input) and to write data to floppy disk(output).   
  • Magnetic Tape Drive

Magnetic Tape drive is an input/output device. It has read/write heads to read data from magnetic tape(input) and to write data to magnetic tape(output).
  • CD-Writer / CD-Recorder
CD-Writer is an input/output device. It is used to store data on CD. It is used to read data from CD(input) and to write data to CD(output).
  • DVD-Writer / DVD-Recorder

DVD-Writer is an input/output device. It is used to store data on DVD. It is used to read data from DVD(input) and to write data to DVD(output).
Read More...

Recent Posts

Sponsored Links
.