Q.5. What are input/output devices? Give examples of input/output devices.(2011-12)
Or Write the short notes on:
1. VDU (Visual Display Unit),
2. Punched card reader, 3. Keyboard,
4. Light pen,
7. Digitisers and graphics table,
8. Game device.
The input unit links the external environment with the computer system by allowing data and instruction to enter the computer system before any computations can be performed. Regardless of their form, data and instructions are transformed into the binary codes that the computer is designed to accept.
Various input devices are:
1. Punched Card Reader: It is a very old device used to input data into the computer. It was used with the first and second generation of computers but has been outdated now.
These devices were used to read data/instructions from the punched cards. A typical punched card contains 80 columns and 12 rows with one column containing one character. The information was represented on them by the combination of a certain pattern of punched holes.
2. Keyboard: Keyboard is one of the most important input devices for a computer. At present, it is the most widely used input device. It is used to type in letters, numbers and other characters. You can type instructions into your computer or you can use the keyboard to type up documents and other papers, Keyboards are a type of keypads similar to a typewriter with a set of buttons that you press to input data into your computer.
The various keys in the keyboard are as follows:
(a) Alphabet Keys: The typing keys are just the keys containing the twenty-six letters of the alphabet. These keys have a QWERTY set-up, QWERTY stands for the first six letters in the top row of the standard letter keys.
(b) Numeric Keys: The numeric keypad is the group of 17 keys on the very right of your keyboard. It includes all of the numbers from 0 to 9, a plus sign, a minus sign and a few other keys. If you look closely, you will realise that the arrangement of the keys on a numeric keypad on your keyboard is quite similar to the arrangement of the keys on the calculator because many computers are used for business purpose and to input numbers into a computer, the numeric keypad was designed. This made it easier and faster to input numbers.
(C) Function Keys: The function keys can be found in a row at the very top of your keyboard. They e labelled ‘F1, F2, F3’ all the way up to ‘F12’. These function keys are mainly used to simplify the alculations. They perform special commands depending on which application is open. For example, in almost all applications, pressing F1 opens a help menu. Also the function keys can be combined with other keys like the control keys to perform different tasks.
(d) Special Keys: The control keys are special keys like Del (delete), Ctrl (control), Alt (alternate), Shift and Enter
(i) The Delete (or backspace) key is used to erase characters in a word document.
(ii) The Esc (escape) key is generally used to exit out of a program or application.
(iii) An Enter key is used to execute a function or command is carried out.
(iv) The Tab key is primarily used to indent in a word document.
The shift key is often used in conjunction with other keys. For example, pressing shift and a letter, will make the letter capital, while pressing shift and a number, will display the character shown right above the number.
Finally, there are the Ctrl and Alt keys. Like the Shift key, these are also used in conjunction with other keys and they usually perform functions similar to those of the function keys.
There are also the cursor movement keys. These are the arrows shaped like an inverted T located between the typing keys and the numeric keypad. These keys are used to move the cursor around on your screen. For example, if you were in a word document, the blinking cursor will move up and down to different lines if you press up and down cursor movement keys.
MBA 1st Year Software Long Questions Answers Study Material Notes
3. Mouse: It is a pointing device, which is quite handy for many visual applications. It has a long wire (similar to a mouse tail) connected to the computer, therefore it is called as mouse, a ball underneath, roll as the mouse moves across the mouse pad. The cursor on the screen follows the motions of the mouse, buttons on the mouse can be clicked or double clicked to perform tasks, like to select an icon on the screen or to open the selected documents.
4. Digitizers and Graphics Table: Digitizers are the devices that convert drawing, photos, etc. to digital signal. Also called as digitizing tablet, it consists of an electronic tablet and a cursor or pen. This cursor is similar to a mouse (also called a puck). Pen, also called as stylus looks like a small ball point pen that uses an electronic head instead of ink in it.
A graphics table is a computer based terminal with additional features for creating, storing and printing picture, we can create an image of a picture by simply moving a stylus on the picture. As the stylus moves, the picture is created and drawn on the screen for checking. The picture can be stored or printed out on a plotter.
A graphics table can be used for tracing existing documents, such as drawings, company logos, maps or cartoons for integrating them with reports or for creating new Ledge B pictures.
5. Light Pen: It is another pointing device used to choose a displayed menu. This pen consists of a light pen. When user moves the tip of a light pen on the surface of the screen, the light causes the photocell to respond and pulses are used for graphics and to draw directly on the CAD terminal.
6. Game Devices (Joystick and Game Pad): In these devices, the cursor in monitor is controlled by vertical stick. This stick moves the graphic cursor in the same direction as its own. It has a button on top that is used to select the option which is pointed by a cursor. It is same as a mouse where cursor stops moving as one stops moving the mouse.
7. Trackball: A trackball is a pointing device and is similar to a mouse. The ball is normally placed on the top along with the buttons. To move the graphics cursor around the screen, the ball is simply rolled with the fingers. The trackballs are most commonly used with computers but are also found in electronics like arcade games, mixing boards and self serve kiosks.
The output unit supplies information and results of computation to the outside world. Thus, it links the computer with the external environment. As computers work with binary code, the results produced are in the binary form. A special interface called the output interfaces attached to the output unit converts the information in binary form to human acceptable form. The various output devices are:
1. VDU (Visual Display Unit): Monitors are the most popular output devices used today for producing soft copy output. A monitor displays information in visual form, using text and graphics. The portion of the monitor that displays the information is called the screen. Like a television screen, a computer screen can show still or moving pictures.
There are two basic types of monitors:
1. CRT (Cathode Ray Tube) monitors, and
2. LCD (Liquid Crystal Display) monitors.
Both types produce sharp images, but LCD monitors have the advantage of being much thinner and lighter. CRT monitors, however, are generally more affordable. They are shown in the Fig. (f) and (g).
The CRT monitors look much like a television and are used with non-portable computer systems. CRT monitors are available in monochrome (i.e. black and white) and colour. Monochrome monitor have only one CRT for white colour in order to produce black and white output. Colour monitor have three CRTs for red, green and blue colours to produce coloured output.
The flat-panel monitors (like LCDs and TFTs) are thinner, lighter and consume low energy. LCD stands for Liquid Crystal Display. TFT stands for Thin Film Transistor. LCDs are commonly used with portable computer systems (like laptop computers), watches and calculators.
2. Speakers: Speakers are used to play sound. They may be built into the system unit or connected with cables. Speakers allow you to listen to music and hear sound effects from your computer.
Once you have recorded a sound file, you can use your speakers to listen to the music or other sound. Speakers change the electrical signals from your sound file and convert them into sound waves that we can hear.
3. Printer: Printer is one of the most popular form of output of a computer system. You can use your printer when you want to print an essay you typed-up from your English class. When you want to print out a letter picture which your aunt e-mailed you and when you want to print out a letter you type to your grandfather. Printer is an important part of your home, office system and are used to perform a variety of tasks.
4. Plotter: Many engineering design applications, like architectural plan of a building, design of mechanical components of an aircraft or a car, etc. often require high-quality, perfectlyproportioned graphic output on large sheets. A special type of hard-copy output device, called plotter, is used for this purpose. Two types of plotter are:
(a) Drum Plotter: In a drum plotter, the paper, on which
the design has to be plotted, is placed over a drum, which can rotate in both clockwise and anti-clockwise directions. The mechanism consists of one or more penholders mounted perpendicular to the drum’s surface. The pens clamped in the holders can move from left to right, or right to left to produce horizontal motion. Under computer control, the drum and the pens move simultaneously to draw the designs and graphs on the paper-sheet placed on the drum. Since each pen is program selectable, pens having ink of different colours can be mounted
in different holders to produce multi-coloured designs.
(b) Flatbed Plotter: A flatbed plotter plots a design or graph on a sheet of paper, which is spread and fixed over a rectangular flatbed table. The mechanism consists of one or more penholders. The pens clamped in the holders can move from left to right, or right to left to produce
horizontal motion. Under computer control, the pens move in the required manner to draw the designs and graphs on the sheet placed on the flatbed table. There may be more than one pen. Each pen is program selectable. Pens having ink of different colours can be mounted in different holders to produce multi-colour designs.
Q.6. Write short notes on the following:
1. Electronic card reader,
2. Handwritten character reader,
3. Digital video camera,
4. Magnetic tape,
5. Floppy disk,
6. Hard disk,
Ans. 1. Electronic Card Reader: Electronic cards are small plastic cards having encoded data. An electronic card reader, which is connected to the computer, is an input device and is used to read the data which is encoded on an electronic card and transfer it to the computer for further processing.
Electronic cards are often used by banks and issued to the account holders for use in ATMs (Automatic Teller Machines). An ATM has an electronic card reader associated with it. When a customer inserts his/her ATM card into the ATM, its reader reads the data encoded on the card and transmits it to the bank’s computer, which activates the customer’s account.
2. Handwritten Character Reader: Handwritten character reader is an input device used to convert handwritten data into computer usable form. This device had been devised after improving the OCR technology, which converts only typewritten data. Because handwriting varies widely, specific guidelines must be followed so that these readers can interpret the characters accurately. Handwriting guidelines for OCR readers are:
(a) Make the size of each character fairly large.
(b) Print using block letters and numbers.
(c) While writing characters or letters that has a loop (like, 6,9,g), carefully connect the lines.
(d) While writing characters or letters with connecting lines (like T, 1,4,5), carefully connect the lines.
(e) Don’t use script (it connects the letters) and don’t connect series of zeroes together in numbers.
3. Digital Video Camera: A digital video camera is an input device, which takes continuous images by breaking down the images into a series of lines (or scan lines). Each line is scanned once at a time and the continuously varying intensities of red, green and blue light across the line.
When user presses a particular button in the digital camera, it captures and digitizes the image. compresses it and stores that image in its memory situated inside.
4. Magnetic Tape: Magnetic tapes are used for large computers like mainframe computers where large volume of data is stored for a longer time. In PC also you can use tape in the form of cassettes. The cost of storing data in tapes is inexpensive. Tapes consist of magnetic materials that store data permanently. It can be 12.5 mm to 25 mm wide plastic film type and 500 metre to 1200 metre long which is coated with magnetic material. The tape is connected to the central processor and information is fed into or read from the tape through processor. It is similar to cassette tape record.
5. Floppy Disk: It is similar to magnetic disk discussed above. They are 5.25 inch or 3.5 inch in diameter. They come in single or double density and floppy disks (3.5 inch or 1.44 MB) recorded on one or both surface of the diskette. The capacity of a 5.25 inch floppy is 1.2 mega bytes whereas for 3.5 inch floppy, it is 1.44 mega bytes. It is cheaper than any other storage devices and is portable. The floppy is a low cost device that is particularly suitable for personal computer system.
6. Hard Disks: Hard disks, sometimes are also called hard drives for the computer. Unlike the computer’s memory, hard drives are not within the circuitry of the computer and are not on the motherboard itself.
There is atleast one hard disk within every single modern desktop computer. They are used to store large amounts of information. The data stored in a hard disk will not be erased when the computer is turn off, like the data stored in the computer’s Random Access Memory (RAM). When the central processing unit of a computer needs to use information stored on the hard disk, the data will be copied from the hard disk to the computer’s RAM. This is so, a computer can permanently store large amounts of information and operates at fast speed at the same time.
Modern hard disks can store anywhere between 10 and 40 gigabytes 1 gigabyte is 1 billion bytes and one byte is 8 bits. Bits contain a single binary digit-1 or 0. Eight of these bits combined to form one byte and one byte is used to represent a single letter, number punctuation mark or another special character. Hard disks can be used to store any kind of information from text files to graphics in the form of the instructions in a software application.
7. Compact Disk-Read Only Memory (CD-ROM): CD-ROM disks are made of reflective metals. CD-ROM is written during the process of manufacturing by high power laser beam. Here, the storage density is very high, storage cost is very low and access time is relatively fast. Each disk is approximately 4- inches in diameter and can hold over 600 MB of data. As the CD-ROM can be read only we cannot
write or make changes into the data contained in it.
Q.7, Identify the different types of printers and give a brief description of each.
Or What is a printer? Name different types of printers available. Explain any one of them. (2011-12)
Or What is impact printer? Explain any one of them.
Ans. Printer: A printer is a most commonly used output device for producing hard-copy output. A printer transfers data from a computer into paper. Some printers produce only letters and numbers whereas other can also produce graphics.
You don’t need a printer to use with your computer but having one, allows you to print e-mail, cards, invitations, announcements and other materials. Many people also like being able to print their own photos even at home.
Printer is broadly classified into two types:
1. Impact printers.
2. Non-impact printers.
1. Impact Printers
It makes contact with the paper. It usually forms the print image by pressing an inked ribbon against the paper with a hammer like mechanism. These printer functions as typewriter does. The main disadvantage is that they are relatively slow and noisy. Some impact printers are described below:
(a) Dot-matrix Printer (DMP): It comes in the category of impact printer. Dot-matrix printer is also known as character printer, since they print one character at a time. It form characters and all kinds of images as a pattern of dots, as shown in the given figure. A dot-matrix printer has a print head, which contains an array of pins. This print head can move horizontally across the paper. These pins of print head can be activated independent of each other to extend and strike against an inked ribbon in order to form a pattern of dots on the paper. So, to print a character, the printer activates the appropriate set of pins as the print head moves horizontally (from left to right and from right to left).
Dot-matrix printer has the ability to print any character of any font (such as Times New Roman, Courier New, Arial, etc.) and size (8, 10, 12 or more) and graphics, such as charts and graphs.
Dot-matrix printer is noisy. It prints usually 30 to 600 characters per second. It is cheap in terms of both initial cost and cost of operation.
(b) Drum Printer: Drum printer comes in the category of impact printer: Drum printer is line printer, which prints one whole line at a time. It consists of a solid cylindrical drum with raised characters on its surface in the form of circular bands. Each band consists of all the printing characters supported by the printer in its character set. The total number of bands is equal to the maximum number of characters that can be printed on a line.
This printer has a set of hammers which are mounted in front of the drum in a manner that an inked ribbon and paper can be placed between the hammers and the cylindrical drum. The number of hammers is equal to the total number of bands on the drum. Therefore, if there are 132 print positions for one line, the printer will have 132 hammers.
The drum rotates at a high speed and activating the appropriate hammer, when the raised character on the band at the print position passed below it, prints a character at a print position. As compared to the dot-matrix printer, drum printer output is very clear but it does not have the ability to print any shape of characters, different sizes of print and graphics, such as charts and graphs.
Similar to dot-matrix printer, drum printer is also noisy in operation. It prints usually 300 to 2000 lines per minute. It is cheap in terms of both initial cost and cost of operation.
MBA 1st Year Software Long Questions Answers Study Material Notes
(c) Chain/Band Printer: Chain/Band printer comes in the category of impact printer. Chain/ Band printers are line printers, which print one line at a time. It consists of a metallic chain/ band with raised characters on it. Chain/Band consists of all printing characters supported by the printer in its character set. This printer has a set of hammers which are mounted in front of the chain/band in a manner that an inked ribbon and paper can be placed between the hammers and the chain/band. The total number of hammers is equal to the total number of print positions in a line. Therefore, if there are 132 print positions in one line, the printer will have 132 hammers. The chain/band rotates at a high speed and activating the appropriate hammer, when the raised character on the chain/band at the print position passes below it, prints a character at a print position. As compared to the dot-matrix printer, chain/band printer output is very clear but it does not have the ability to print any shape of characters, different sizes of print and graphics, such as charts and graphs.
Similar to dot-matrix printer, chain/band printer is also noisy in operation. It prints usually 400 to 3000 lines per minute. It is cheap in terms of both initial cost and cost of operation.
2. Non-Impact Printers
Printers that don’t strike hammers against ribbon or paper when they print, are non-impact printers. These printers generate much less noise than impact printers do. They are:
(a) Inkjet Printer: Inkjet printer comes in the category of non-impact printers. It is the most popular printer for the home. It can print in black and white or in full colour and can produce high-quality photographs when used with special paper.
Inkjet printer is character printer, which form characters and all kinds of images by spraying small drops of ink on the paper. Inkjet printer has a print head, which contains upto 64 any nozzles which can be selectively heated up in a few microseconds by a circuit register integrated on the print head. When the register heats up, the ink near it ejected through the nozzle and makes a dot on the paper. To print a character the printer selectively heats the appropriate set of nozzles as the print head moves horizontally from top to bottom.
Inkjet printer produces higher quality output because they form characters by very tiny ink Ots. A high-resolution inkjet printer has the resolution of around 360 dots per inch or more. hkjet printer can print any shape of characters in any size and graphics, such as charts and graphs. It is quiet in operation. It can print 40 to 300 characters per second.
(b) Laser Printer: Laser printer comes in the category of non-impact printers. It is a page printer, which prints one page at a time. It has a laser beam source, a multi-sided mirror, a photoconductive drum and a toner (tiny particles of charger ink).
To print a page of output, the mirror focuses the laser beam on the surface of the drum in a manner so as to create the patterns of characters images to print on the paper. As the drum is photoconductive, a difference in electric charge is created on those portions of the drum surface, which are exposed to the laser beam. As a result, the toner sticks to the drum in the places, where the laser beam has charged the drum’s surface. The toner (on the drum) is then permanently focused on the paper with heat and pressure to generate the printed output. The drum is then rotated and cleaned with a rubber blade to remove the toner sticking to its surface to prepare the drum for the next page printing.
Laser printer produces very high quality output, because it forms characters by very tiny ink particles. The resolution of laser printers is from 600 to 1200 dpi (dots per inch).
Laser printer can print any shape of characters in any size and graphics, such as charts and graphs
Laser printer is very quiet in operation. Low speed laser printer can print 4 to 12 pages per minute. Very high-speed laser printer can print 500 to 1000 pages per minute. It is costly than other printers.
Q.8. What is software? Explain system and application software. Enlist system and application software.(2012-13)
Or Classify different types of software with the help of suitable examples. Discuss the concept of open source operating system.(2010-11, 15-16)
Ans. Software: Software means a collection of programs whose objective is to enhance the capabilities of the hardware machine. A sequence of instructions written in a language that can be understood by a computer is called a computer program.
Computer software comprises of set of instructions that help arithmetic and logical capabilities of the hardware units of system to perform. It is the planned step-by-step instructions required to turn data into information. Software can be broadly classified into two categories:
1. System Software
System software is a collection of system programs, which perform the basic functions which are necessary to start and operate a computer. These programs do not solve specific problems. There are general programs written to assist humans in the use of the computer system by performing tasks, such as controlling all of the operations required to move the data in and out of a computer and all the steps in executing an application program. System software is classified into three categories:
(a) System Control Software: It includes programs that monitor, control, coordinate and manage the resources and functions of a computer system. The mostly used system control software is Operating System (OS).
(b) System support software: It includes programs that facilitate the smooth and efficient operation of a computer. Some system support software are utility programs (used for formatting disks, searching free space on a disk, storing and merging data, etc.), translators (such as compilers, interpreters and assemblers used in computer languages); data base management systems (used to manage data on disks efficiently).
(c) System Development Software: It is a collection of programs (an example is Computer-Aided Software Engineering or CASE) that assist system developers in designing and developing information systems (such as college information system which describes the number of courses running in the college, details of staff members, students and results).
2. Application Software
Application software is a set of application programs, which are designed to perform people related tasks. For example, a payroll package produces pay slips as the major output. Similarly, a program written by a scientist to solve his particular research problem is also application software. Application software is classified into two categories: