Topic Wise Notes: Application of Computers
Please note: The answers provided below, are just for reference. Always consult your college professor if you have any queries.
Q.1. Explain Data Entry & output devices. Give examples of each.
Input Devices
Input devices are necessary to convert our information or data into a form that can be understood by the computer. A good input device should provide timely, accurate, and useful data to the main memory of the computer for processing. The following are the most useful input devices.
Keyboard:
This is the standard input device attached to all computers. The layout of the keyboard is just like the traditional typewriter of the type QWERTY. It also contains some extra command keys and function keys. It contains a total of 101 to 104 keys. A typical keyboard used in a computer you have to press the correct combination of keys to input data. The computer can recognize the electrical signals corresponding to the correct key combination and processing is done accordingly.
Mouse:
The mouse is an input device that is used with your personal computer. It rolls on a small ball and has two or three buttons on the top. When you roll the mouse across a flat surface the screen censors the mouse in the direction of mouse movement. The cursor moves very fast with mouse giving you more freedom to work in any direction. It is easier and faster to move through a mouse
Types of Mouse
Trackball Mouse: In this, the ball is rolled at one place rolling the mouse on the tabletop.
Optical Mouse: It uses a light beam to detect movement.
Wireless Mouse: It is a mouse without a cable. This mouse works up to one and a half meters away from the computer.
Light Pen Mouse: It uses a light-sensitive detector, requiring you to hold a pen and point it at the screen.
Joystick Mouse: It usually includes two upright sticks which are moved with the hand and the button is pressed on either stick.
Scanner
The keyboard can input only text through keys provided in it. If we want to input a picture the keyboard cannot do that. The scanner is an optical device that can input any graphical matter and display it back. The common optical scanner devices are:
Magnetic Ink Character Recognition (MICR): This is widely used by banks to process large volumes of cheques and drafts. Cheques are put inside the MICR. As they enter the reading unit the cheques pass through the magnetic field which causes the read head to recognize the character of the cheques.
Optical Mark Reader (OMR): This technique is used when students have appeared in objective type tests and they had to mark their answer by darkening a square or circular space by pencil. These answer sheets are directly fed to a computer for grading where OMR is used.
Optical Character Recognition (OCR): This technique unites the direct reading of any printed character. Suppose you have a set of handwritten characters on a piece of paper. You put it inside the scanner of the computer. This pattern is compared with a site of patterns stored inside the computer. Whichever pattern is matched is called a character read. Patterns that cannot be identified are rejected. OCRs are expensive though better the MICR.
Barcode Reader (BCR): A barcode reader is an electronic device for reading printed barcodes. Like a flatbed scanner, it consists of a light source, a lens and a light sensor translating optical impulses into electrical ones. Additionally, nearly all barcode readers contain decoder circuitry analyzing the barcode’s image data provided by the sensor and sending the barcode’s content to the scanner’s output port.
Output Devices
Visual Display Unit
The most popular input/output device is the Visual Display Unit (VDU). It is also called the monitor. A Keyboard is used to input data and a Monitor is used to display the input data and to receive messages from the computer. A monitor has its own box which is separated from the main computer system and is connected to the computer by cable. In some systems, it is compact with the system unit. It can be color or monochrome. Currently, there are two types of visual display units (VDU) available. These help in displaying what we have entered into the computer, as well as the output that is derived from the computer after a process.
CRT – Cathode Ray Tube, which comes in monochrome, soft white, and color forms. These are normally used with Desktop computers.
LCD – Liquid Crystal Display, also in soft white and color. These are sleek and mostly used in portable computers, viz. palm-tops, and laptops. On the same lines, there are LCD overhead projectors, which when interfaced with the computer the output could be projected on to a screen in a larger form for convenient viewing in meetings, demonstrations, and presentations.
Terminals
It is a very popular interactive input-output unit. It can be divided into two types: hard copy terminals and soft copy terminals. A hard copy terminal provides a printout on paper whereas soft copy terminals provide a visual copy on the monitor. A terminal when connected to a CPU sends instructions directly to the computer. Terminals are also classified as dumb terminals or intelligent terminals depending upon the work situation.
Printer
It is an important output device that can be used to get a printed copy of the processed text or result on paper. There are different types of printers that are designed for different types of applications. Depending on their speed and approach of printing, printers are classified as impact and non-impact printers. Impact printers use the familiar typewriter approach of hammering a typeface against the paper and inked ribbon. Dot-matrix printers are of this type. Non-impact printers do not hit or impact a ribbon to print. They use electrostatic chemicals and ink-jet technologies. Laser printers and Ink-jet printers are of this type. This type of printers can produce colour printing and elaborate graphics. A computer printer is a computer peripheral device that produces a hard copy (permanent human-readable text and/or graphics, usually on paper) from data stored in a computer connected to it. The world’s first computer printer was a 19th-century mechanically driven apparatus invented by Charles Babbage for his Difference Engine.
Non-impact printers: In these printers, the print head does not physically touch the paper; but makes impression on the paper by different techniques viz. heat, light and liquid. All these are versatile, high-speed letter-quality printers that work almost silently. Monochrome, colour, and photo printers – A monochrome printer can only produce an image consisting of one colour, usually black. A monochrome printer may also be able to produce gradations of the tone of that colour, such as a scale. A colour printer can produce images of multiple colours.
Toner-based printers – Laser printers refer to the method used to adhere toner to the media. The advent of cost-effective, precision lasers has made them the dominant toner-based monochrome printer type for home and office applications. Another toner-based printer is the LED printer which uses an array of LEDs instead of a laser to cause toner adhesion.
Inkjet printers – Inkjet printers spray very small, precise amounts of ink onto the media. For colour applications including photo printing, inkjet methods are dominant. Inkjet printers or bubble-jet printers are one of the most commonly used printers. They consist of nozzles that produce very small ink bubbles that turn into tiny droplets of ink. The dots formed are the size of tiny pixels. Ink-jet printers can print high-quality text and graphics. They are also almost silent in operation. They are cheaper than laser printers but are expensive to run as their cartridges need to be frequently replaced.
Impact printers – These printers physically touch the paper and make the impression on it, hence these are called impact printers. These are very noisy printers. Impact printers rely on a forcible impact to transfer ink to the media, similar to typewriters, that are typically limited to reproducing text. A daisy wheel printer is a specific type of impact printer where the type is moulded around the edge of a wheel. A golf ball typewriter is similar to the daisy wheel type but has the characters distributed over the face of the globe shape.
Dot-matrix printers – In the general sense many printers rely on a matrix of pixels, or dots, that together form the larger image. However, the term dot matrix printer is specifically used for impact printers that use a matrix of small pins to create precise dots. The advantage of dot-matrix over other impact printers is that they can produce graphical images in addition to text; however, the text is generally of poorer quality than impact printers that use letterforms. Dot-matrix printers can either be character-based or line-based (that is, a single horizontal series of pixels across the page), referring to the configuration of the print head. At one time Dot matrix printers were one of the more common types of printers used for general use – such as for home and small office use. Such printers would have either 9 or 24 pins on the print head. 24 pin print heads were able to print at a higher quality.
Line printers – Line printers, as the name implies, print an entire line of text at a time. Two principle designs existed. In drum printers, a drum carries the entire character set of the printer repeated in each column that is to be printed. In chain printers (also known as train printers), the character set is arranged multiple times around a chain that travels horizontally past the print line. In either case, to print a line, precisely timed hammers to strike against the back of the paper at the exact moment that the correct character to be printed is passing in front of the paper. The paper presses forward against a ribbon which then presses against the character form and the impression of the character form is printed onto the paper. These printers were the fastest of all impact printers and were used for bulk printing in large computer centres. They were virtually never used with personal computers and have now been partly replaced by high-speed laser printers.
Daisy wheel / Golf ball printer: A small Daisy-like structure/golf ball-like structure the fonts forming characters is embossed. The wheel/ball rotates at a speed and a hammer hits the wheel or ball, based on the instruction from the computer when a particular character is on the side of the paper, which in turn hits a ribbon which makes the character print on the paper. The print out is called a letter-quality printout, since complete characters are printed, unlike dots in a dot matrix printer. These cannot print graphs etc.
Q.2. Write short notes on: (a) Difference between hardware and software.
HARDWARE | SOFTWARE |
|---|---|
Hardware is a physical parts computer that cause processing of data. | Software is a set of instruction that tells a computer exactly what to do. |
It is manufactured. | It is developed and engineered. |
Hardware can not perform any task without software. | Software can not be executed without hardware. |
As Hardware are physical electronic devices, we can see and touch hardware. | We can see and also use the software but can’t actually touch them. |
It has four main categories: input device, output devices, storage, and internal components. | It is mainly divided into System software, Programming software and Application software. |
Hardware is not affected by computer viruses. | Software is affected by computer viruses. |
It can not be transferred from one place to another electrically through network. | But, it can be transferred. |
If hardware is damaged, it is replaced with new one. | If software is damaged, its backup copy can be reinstalled. |
Ex: Keyboard, Mouse, Monitor, Printer, CPU, Hard disk, RAM, ROM etc. | Ex: Ms Word, Excel, Power Point, Photoshop, MySQL etc. |
(b) Types of printers.
Non-impact printers: In these printers, the print head does not physically touch the paper; but makes impression on the paper by different techniques viz. heat, light and liquid. All these are versatile, high-speed letter-quality printers that work almost silently. Monochrome, colour, and photo printers – A monochrome printer can only produce an image consisting of one colour, usually black. A monochrome printer may also be able to produce gradations of the tone of that colour, such as a scale. A colour printer can produce images of multiple colours.
Toner-based printers – Laser printers refer to the method used to adhere toner to the media. The advent of cost-effective, precision lasers has made them the dominant toner-based monochrome printer type for home and office applications. Another toner-based printer is the LED printer which uses an array of LEDs instead of a laser to cause toner adhesion.
Inkjet printers – Inkjet printers spray very small, precise amounts of ink onto the media. For colour applications including photo printing, inkjet methods are dominant. Inkjet printers or bubble-jet printers are one of the most commonly used printers. They consist of nozzles that produce very small ink bubbles that turn into tiny droplets of ink. The dots formed are the size of tiny pixels. Ink-jet printers can print high-quality text and graphics. They are also almost silent in operation. They are cheaper than laser printers but are expensive to run as their cartridges need to be frequently replaced.
Impact printers – These printers physically touch the paper and make the impression on it, hence these are called impact printers. These are very noisy printers. Impact printers rely on a forcible impact to transfer ink to the media, similar to typewriters, that are typically limited to reproducing text. A daisy wheel printer is a specific type of impact printer where the type is moulded around the edge of a wheel. A golf ball typewriter is similar to the daisy wheel type but has the characters distributed over the face of the globe shape.
Dot-matrix printers – In the general sense many printers rely on a matrix of pixels, or dots, that together form the larger image. However, the term dot matrix printer is specifically used for impact printers that use a matrix of small pins to create precise dots. The advantage of dot-matrix over other impact printers is that they can produce graphical images in addition to text; however, the text is generally of poorer quality than impact printers that use letterforms. Dot-matrix printers can either be character-based or line-based (that is, a single horizontal series of pixels across the page), referring to the configuration of the print head. At one time Dot matrix printers were one of the more common types of printers used for general use – such as for home and small office use. Such printers would have either 9 or 24 pins on the print head. 24 pin print heads were able to print at a higher quality.
Line printers – Line printers, as the name implies, print an entire line of text at a time. Two principle designs existed. In drum printers, a drum carries the entire character set of the printer repeated in each column that is to be printed. In chain printers (also known as train printers), the character set is arranged multiple times around a chain that travels horizontally past the print line. In either case, to print a line, precisely timed hammers to strike against the back of the paper at the exact moment that the correct character to be printed is passing in front of the paper. The paper presses forward against a ribbon which then presses against the character form and the impression of the character form is printed onto the paper. These printers were the fastest of all impact printers and were used for bulk printing in large computer centres. They were virtually never used with personal computers and have now been partly replaced by high-speed laser printers.
Daisy wheel / Golf ball printer: A small Daisy-like structure/golf ball-like structure the fonts forming characters is embossed. The wheel/ball rotates at a speed and a hammer hits the wheel or ball, based on the instruction from the computer when a particular character is on the side of the paper, which in turn hits a ribbon which makes the character print on the paper. The print out is called a letter-quality printout, since complete characters are printed, unlike dots in a dot matrix printer. These cannot print graphs etc.
OR (a) Classification of computers.
On The Basis Of Purpose
General Purpose Computers
These are designed to perform a range of tasks. They have the ability to store numerous programs, but lack in speed and efficiency comparatively.
Special Purpose Computers
Specific purpose computers are designed to handle a specific problem or to perform a specific task. A set of instructions is built into the machine.
On The Basis Of Size
Microcomputers
Microcomputers are connected to networks of other computers.
The price of a microcomputer varies from each other depending on the capacity and features of the computer.
Microcomputers make up the vast majority of computers.
A single user can interact with this computer at a time.
It is a small and general-purpose computer.
Mini Computer
Mini Computer is a small and general-purpose computer.
It is more expensive than a microcomputer.
It has more storage capacity and speed.
It designed to simultaneously handle the needs of multiple users.
Mainframe Computer
Large computers are called Mainframes.
Mainframe computers process data at very high rates of speed, measured in the millions of instructions per second.
They are very expensive than the microcomputer and minicomputers.
Mainframes are designed for multiple users and process vast amounts of data quickly.
Examples:- Banks, insurance companies, manufacturers, mail-order companies, and airlines are typical users.
Super Computers
The largest computers are Super Computers.
They are the most powerful, the most expensive, and the fastest.
They are capable of processing trillions of instructions per second.
On The Basis Of Functionality/ Data Handling
Analog Computers
An Analog Computer is a form of computer that uses continuous physical phenomena such as electrical, hydraulic, or mechanical quantities to model the problem being solved.
They work on the principles of measuring in which the measurements obtained are translated into data.
Modern Analog Computers usually employ electrical parameters such as voltages, resistances or currents to represent the quantities being manipulated.
They measure continuous physical magnitudes
Digital Computers
A computer that performs calculations and logical operations with quantities represented as digits, usually in the binary number system.
They process data into a digital value (0s and 1s).
They give results with more accuracy at a faster rate.
Hybrid Computers
A combination of computers, those who are capable of inputting and outputting in both digital and analog signals.
A Hybrid computer system set up offers a cost-effective method of performing complex simulations.
They incorporate the measuring feature of an analog computer and counting feature of a digital computer.
For computational purposes, these computers use analog components and store digital memories are used.
(b) Parts of a Window.
Parts of a Windows in Computer
Microsoft Windows, the most widely used operating system in the world, employs the metaphor of a window for navigation and file management. Understanding the parts of a window is the first step to knowing how to navigate through the operating system.
The Title Bar
At the top of every window is the title bar. The center of the title bar displays either the name of the program you are currently working in or relevant information about what is happening in the program at any given moment. When the window is not maximized, this is where you can click and drag to move the window to a new location on the screen.
Minimize, Maximize, Close Buttons
In the upper right-hand corner of the window are the three buttons used to minimize, maximize, and close the window. Minimizing the window shrinks it to nothing and places it out of sight. Maximizing the window makes it fill the screen and locks it into position so that it cannot be moved by dragging the title bar. Closing the window shuts down the program.
The Scroll Bar
On the right side of the window is the scroll bar, which appears only if there is information to be displayed beyond the bottom range of the current window size. Clicking and dragging on the slider in the scroll bar moves the contents of the window up or down so you can view all of the data available.
The Menu Bar
Most programs will have a menu bar visible in the upper left-hand corner of the window. The menu bar appears as the text for most programs and usually starts with “File” at the far left. Accessing the menu allows you to view various commands available to that program, including closing the program or the window. The Work Space
The workspace is all of the areas inside the window where data for the current program is displayed. usually, the workspace will have a white background, but it is possible to customize this in all versions of Windows, and it may vary by program.
Q.3. Expand any five of the following terms:
(a) URL : Uniform Resource Locator
(b) LED : Light Emitting Diode
(c) OLE : Object Linking & Embedding
(d) MIPS : Microprocessor without Interlocked Pipelined Stages
(e) BIOS : Basic Input Output Systems
(f) FAT : File Allocation Table
(g) BCD : binary-coded decimal
(h) NIC : Network Interafce Card
(i) KB : Kilo Byte
(j) HDD : Hard Disk Drive
Q.4. Give two examples of each:
(a) High Level Languages
Python, Visual Basic
(b) Secondary storage devices
USB thumb drive, SD card
(c) Cable
Twisted Pair, Optical Fibre
(d) Wild card characters
percent(%), asterisk(*)
(e) Non-Impact printers
laser printer, inkjet printer
Q.5. Give DOS command for any five of the following:
(a) To clear the screen : CLS
(b) To format a drive : FORMAT
(c) To delete the existing file : DEL
(d) To remove a sub-directory : RD
(e) To sort the contents of the file : SORT
(f) To display the version of operating system : VER
(g) To prepare a new hard disk : FDISK
Q.6. State True or False:
(a) MS PowerPoint is a part of windows operating system. False
(b) Menu contains list of related commands. True
(c) Printer is an output device. True
(d) In MS-EXCEL, the formula always starts with an “equal to” sign. True
(e) Internet explorer is a browsing tool. True
Q.7. Match the following:
(a) Nibble (i) Network cable
(b) Speech recognition (ii) 4 bits
(c) Windows (iii) 0’s and 1’s
(d) Machine Language (iv) Input device
(e) ETHERNET (v) Operating system
Solution:
(a) Nibble (ii) 4 bits
(b) Speech recognition (iv) Input device
(c) Windows (v) Operating system
(d) Machine Language (iii) 0’s and 1’s
(e) ETHERNET (i) Network cable
Q.8. Fill in the blanks.
(a) The Base of binary number system is 0’s and 1’s. (b) Interpreter translates the program line by line. (c) Dir is an Internal command. (d) The default opening screen of a window is called desktop. (e) All deleted files will be found in Recycle bin
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