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(c)  Hard disk

Optical technique is used for CD ROM.

(b)  Kilobyte

(b)  Hard disk 

The device that is used to enter data or instructions in a computer is known as an input device. For example, Keyboard and Mouse.

(d)  Blu-ray

Joystick In computers, a joystick is a cursor control device used in computer games and assistive technology . The joystick, which got its name from the control stick used by a pilot to control the ailerons and elevators of an airplane, is a hand-held lever that pivots on one end and transmits its coordinates to a computer. It often has one or more push-buttons, called switches, whose position can also he read by the computer, light pen-A light pen is a computer input device in the form of a light sensitive wand used in conjunction with a computer’s CRT display. It allows the user to point to displayed objects or draw on the screen in a similar way to a touch screen but with greater positional accuracy.

(b)  Soft copy

Storage capacity of Micro floppy is 1.44 MB.

A computer monitor is an output device that displays the user interface and the information requested by the user.

Memory is classified into two categories: 

1. Primary memory 

2. Secondary memory

Read/ write head

Input devices- keyboard, mouse Output devices- monitor, printers.

A plotter is a printer that interprets commands from a computer to make line drawings on paper with one or more automated pens. Unlike a regular printer, the plotter can draw continuous point-to-point lines directly from vector graphics files or commands. There are different types of plotters: a drum plotter draws on paper wrapped around a drum which turns to produce one direction of the plot, while the pens move to provide the other direction; a flatbed plotter draws on paper placed on a flat surface; and an electrostatic plotter draws on negatively charged paper with positively charged toner.

It is used to print maps, charts, Graphics, design electronic circuits etc.

Tiny -dots on monitor is known as Pixels.

Hole in between floppy disk is known as Index Hole.

All dot matrix printers create characters on paper by striking an inked ribbon with a hard surface. Unlike typewriters, which use a similar mechanism, dot matrix printers do not have fixed character shapes or fonts. Instead, each individual character is formed by the arrangement of a series of pins. This allows dot matrix printers to be used for basic graphical printing and multiple fonts as well as basic text printing — but it gives the printout a characteristic “dotted” appearance. Dot matrix printouts often produce lower-quality text that can be difficult to read. In addition, dot matrix printers generally are noisier than inkjet or laser models.

The print quality produced by a dot matrix printer is significantly affected by the number and size of pins in the print head – even the best dot matrix printers generally can’t match the quality of inkjet or laser printers.

The simplest dot matrix devices use just nine pins to produce each individual character, creating a pixelized, blocky appearance. More complex printers use a larger number of smaller pins, producing greater detail and eliminating the characteristic look of dot matrix text. Common arrangements for these printers include dual 9-pin and 24-pin print heads.

Laser Beam is used for laser printer.

Impact Printers

The speed of a Dot Matrix printer is measured in dpi.

(a) Impact printer

(c) Photocopy technology

CD-ROM (Compact Disc, read-only-memory) is an adaptation of the CD that is designed to store computer data in the form of text and graphics, as well as hi-fi stereo sound. Format of the CD-ROM is the same as for audio CDs: a standard CD is 120 mm (4.75 inches) in diameter and 1.2 mm (0.05 inches) thick and is composed of a polycarbonate plastic substrate , one or more thin reflective metal layers, and a lacquer coating. Today, CD-ROMs are standardized and wall work in any standard CD-ROM drive. CD- ROM drives can also read audio compact discs for music, although CD players cannot read CD-ROM discs.

Laser is not examples of non impact printer.

A printer is an electromechanical device which converts the text and graphical documents from electronic form to the physical form. Generally, they are the external peripheral devices which are connected with the computers or laptops through a cable or wirelessly to receive input data and print them on the papers. A wide range of printers are available with a variety of features ranging from printing black and white text documents to high quality colored graphic images. 

(i) Types of Printers: 

Since the invention of the printing technology, a variety of technologies have been employed in computer printers. Broadly printers are categorized as impact and non impact printers. Impact printers are the type of printers in which a key strikes the paper to make a letter. The examples, of Impact printers are Daisy wheel and Dot matrix printers. While non-impact printers do not operate by striking a head against a ribbon. Inkjet printers and laser printers are the non-impact printers. 

The most popular printers are described below:

1. Daisy Wheel Printers: 

Daisy wheel printers print only characters and symbols and cannot print graphics. They are generally slow with a printing speed of about 10 to 75 characters per second. By 1980, daisy wheel printers were the dominant printers for quality printing but since the prices of laser and inkjet printers have declined and quality of dot matrix printers has been improved, the daisy wheel printers are now obsolete. 

2. Dot Matrix Printers: 

It is a popular computer printer that prints text and graphics on the paper by using tiny dots to form the desired shapes. It uses an array of metal pins known as printhead to strike an inked printer ribbon and produce dots on the paper. These combinations of dots form the desired shape on the paper. Generally they print with a speed of 50 to 500 characters per second as per the quality of the printing is desired. The quality of print is determined by the number of pins used (varying from 9 to 24). 

The key component in the dot matrix printer is the ‘print head’ which is about one inch long and contains a number of tiny pins aligned in a column varying from 9 to 24. The print head is driven by several hammers which force each pin to make contact with the paper at the certain time. These hammers are pulled by small electromagnet (also called solenoids) which is energized at a specific time depending on the character to be printed. The timings of the signals sent to the solenoids are programmed in the printer for each character. The printer receives the data from the computer and translates it to identify which character is to be printed and the print head runs back and forth, or in an up and down motion, on the page and prints the dots on the paper. 

3. Line printer: 

Contains a chain of characters or pins that print an entire line at one time. Line printers are very fast, but produce low-quality print. 

4. Inkjet printers: 

Inkjet printers are most popular printers for home and small scale offices as they have a reasonable cost and a good quality of printing as well. A typical inkjet printer can print with a resolution of more than 300 dpi and some good quality inkjet printers are able to produce full colored hard copies at 600 dpi. 

5. Laser Printers: 

Laser printers are the most popular printers that are mainly used for large scale qualitative printing. They are among the most popularly used fastest printers available in the market. A laser printer uses a slight different approach for printing. It does not use ink like inkjet printers, instead it uses a very fine powder known as ‘Toner’.

1. Input streams

2. Output streams

A stream is an object, where a program can either insert or extract characters to/from it.

The cascading is a way to extract/insert multiple values from/into more than one variable using one cin/cout statement.

cout is used in conjunction with << operator, known as insertion or put to the operator.

It is an input and output device, that allows the user to operate/make selections by simply „ touching the display screen.

The input/output devices provide man to machine communication.

Impact printers form characters or images by striking at a mechanism such as a print hammer or wheel against an inked ribbon, leaving an image on the paper.

It is a special type of keyboard that allows typing without much strain and bending at the wrists. It reduces the muscle and finger pain while typing.

1. Dot-matrix printer:
Dot-matrix printer is an impact printer that prints text and graphics on the paper by using tiny dots to form the shapes. It uses a set of metal pins known as print head to strike an inked printer ribbon and produce dots on the paper. These combinations of dots give the desired shape on the paper. Generally, they print with a speed of 50 to 500 characters per second as per the quality of the printing is desired. The quality of the print is determined by the number of pins used (varying from 9 to 24).

2. Line printers:
It is a high-speed printer capable of printing an entire line at one time. A fast line printer can print as many as 3,000 lines per minute. The disadvantages of line printers are that they cannot print graphics, the print quality is low, and they are very noisy.

3. Inkjet printers:
Ink-jet printers are non-impact line printers. The ink is stored in disposable ink cartridges, often a separate cartridge is used for each of the major colors. It prints by spraying small, electrically charged droplets of ink from nozzles through holes in a matrix at high speed onto paper. Ink-jet printers can print in color and are noiseless and cheaper than a color laser printer. However, they are slower and the print resolution is between 300 and -1200 dpi.

4. Laser printers:
The laser printer uses a laser to draw the image onto the printer’s drum, which carries an electric charge. The parts of the drum hold the electrical charge are able to pick up the dry powder type of ink, also called toner, from within the printer. This ink is then fused to the paper, using heat, as the paper rolls over the drum. After the document is printed, the electrical charge is removed from the drum and the excess toner is collected. Laser printers produce good quality prints with resolutions ranging from 300 dpi to 1200 dpi.

5. Thermal printers:
A thermal printer is a printer which uses heated elements to print. Direct thermal and thermal wax transfer are the two types of thermal printers. These printers are relatively efficient and quiet, and they come in a number of sizes and styles for different printing needs. A thermal printer has a print head containing many small resistive heating pins that on contact, melt wax-based ink onto ordinary paper or burn dots onto a specially coated paper.

A thermal printer is a printer which uses heated elements to print. Direct thermal and thermal wax transfer are the two types of thermal printers. These printers are relatively efficient and quiet, and they come in a number of sizes and styles for different printing needs. A thermal printer has a print head containing many small resistive heating pins that on contact, melt wax-based ink onto ordinary paper or burn dots onto a specially coated paper. Computerized billing, electric and water bills are generators by this method.

There are 101 keys in a standard keyboard.

An optical disc is an electronic data storage medium that can be written upon and read, using a low-powered laser beam.

Tracks are concentric circles, and sectors are pie-shaped blocks on a track.

The different types of computer monitors are CRT monitors, LCD monitors, TFT monitors and LED monitors.

The measurement units of memory are bit and byte.

DRAM is also a volatile memory that uses separate capacitors to store each bit. Capacitors, when not charged, represent the value 0 of a bit and when charged represent the value

1. Since the capacitors discharge with time, they need to be refreshed periodically to maintain the values stored in them. Each memory cell in a DRAM consists of a capacitor and a transistor and these cells are arranged in a square array.

SRAM is a type of RAM and it is a volatile memory. In an SRAM, each bit that stores data is made up of four or six transistors that make up a flip-flop. There are additional transistors that are used to control read and write accesses of storage cells. Each SRAM cell can be in three different states called to read, write and standby. A cell is in the reading state when data has been requested and it is in writing state when the data in the cell is modified. The cell is in the standby state when it is idling.

The joystick is a vertical stick that moves the graphic cursor in the direction the stick is moved. It typically has a button on top that is used to select the option pointed by the cursor. The joystick is used as an input device primarily with video games, training simulators and controlling robots.

A computer mouse is a hand-operated electronic pointing device that controls the coordinates of a cursor on your computer screen as you move it around on a pad.

Magnetic Ink Character Reader/Recognition.

Electrically Erasable Programmable Read-Only Memory.

Thin Film Transistor.

Erasable Programmable Read-Only Memory.