Sem 1 Chap 1 - Computer Technologies - PDF

Unit-1 1. Introducing today’s Technologies, Input, Output and Digital Storage Today’s technology Computers have become integral part of our life they are everywhere to help us with our day to day life such as completing assignment or streaming video on our laptops or mobiles. Technologies are e...

Unit-1 1. Introducing today’s Technologies, Input, Output and Digital Storage Today’s technology Computers have become integral part of our life they are everywhere to help us with our day to day life such as completing assignment or streaming video on our laptops or mobiles. Technologies are everywhere to keep you updated with daily headlines or to cherish your mood with latest song or different apps are available to edit your photos online, in fact we can keep our memories intact on cloud storage. Technology help us to access the information efficiently and effectively and to keep our self-upgraded with new trend we have to keep learning about new terms of technology as much we can. Digital literacy involves having current knowledge and understanding of computers, mobile devices, the web, and related technologies. Let's discuss about computer and its part in brief. What is a Computer? Definition: "A computer is an electronic device, operating under the control of instructions stored in its own memory that can accept data (input), process the data according to specified rules, produce information (output), and store the information for future use. Computers contain many electric, electronic, and mechanical components known as hardware." Desktops A desktop computer is a personal computer built to be used at a desk. This is in contrast both to large mainframe computers, which are not meant to be used at a desk, and to portable computers. It is designed to be in a stationary location, where all of its components fit on or under a desk or table. Components that typically occupy space outside of a desktop include peripheral devices such as a keyboard, mouse, and webcam (input devices); printer (output devices); external hard drive (storage device); and possibly a router and/or modem (communications devices). Depending on the form factor of the desktop, it may also require an external monitor. Some people use the term, system unit, to refer to the case that contains and protects the motherboard, internal hard drive, memory, and other electronic components of the computer from damage. A desktop may have a system unit tower that is a separate device from a monitor.  Laptop computer A laptop, also called a notebook computer, is a thin, lightweight mobile computer with a screen in its lid and a keyboard in its base. Designed to fit on your lap and for easy transport. Laptops have input devices, such as a keyboard, touchpad, and webcam; output devices, such as a screen and speakers, a storage device(s), such as a hard drive and maybe an optical disc drive; and usually built-in wireless communications capability. Some laptops have touch screens. Most can operate on batteries or a power supply or both. Most laptops are designed to have all of the functionality of a desktop computer, which means they can generally run the same software and open the same types of files. However, laptops also tend to be more expensive than comparable desktop computers. How is a laptop different from a desktop? Because laptops are designed for portability, there are some important differences between them and desktop computers. A laptop has an all-in-one design, with a built- in monitor, keyboard, touchpad (which replaces the mouse), and speakers. This means it is fully functional, even when no peripherals are connected. A laptop is also quicker to set up, and there are fewer cables to get in the way. You'll also have to the option to connect a regular mouse, larger monitor, and other peripherals. This basically turns your laptop into a desktop computer, with one main difference: You can easily disconnect the peripherals and take the laptop with you wherever you go. Tablet computers Like laptops, tablet computers are designed to be portable. However, they provide a different computing experience. The most obvious difference is that tablet computers don't have keyboards or touchpads. Instead, the entire screen is touch-sensitive, allowing you to type on a virtual keyboard and use your finger as a mouse pointer. Tablet computers can't necessarily do everything traditional computers can do. For many people, a traditional computer like a desktop or laptop is still needed in order to use some programs. However, the convenience of a tablet computer means it may be ideal as a second computer. All-in-one An all-in-one computer, or AiO, combines the separate tower and monitor of a typical desktop PC setup into a single piece of hardware. It is no different from a desktop PC in terms of basic functionality. There are several advantages AiOs have over desktops. Advantages of All-in-One Computers Easier to transport- The beauty of the AiO computer is the fact that it is relatively small, light and simple. You also do not need to worry about all the cables and the cable management that comes with them. Everything you need- Everything you need is in the box—you may not even need a keyboard or mouse if you purchase a touchscreen AiO. You also don’t need to worry about buying a the cables to connect your laptop to external monitors like you would with a laptop. Touchscreens- Many users prefer touchscreen interface which many AiOs with Windows provide. Their displays are large on average, making them great for applications such as retail kiosks or interactive learning stations. Disadvantages of All-in-One Computers  Can’t be modified or repaired easily- With your standard desktop PC, it’s easy to pop open the case and replace faulty or upgrade to a faster CPU, for instance. On the other hand, AiOs are not designed with modification in mind—you can’t easily get inside the device, and Keep in mind AiO components are specially engineered to fit within its compact confines. In this way, they are like laptops, both in component size and difficulty in upgrading. More expensive- With a desktop : you can just replace whatever you need to and run the latest, cutting-edge software or upgrade your internal storage as need be. For this reason, the AiO may cost more in the long run, since they’ll most likely last about 5-10 years depending on how well you take care of it. Not as powerful- AiOs are designed with the average PC user in mind and are more than capable of meeting the computing needs of most users. However, if you’re a graphic design professional or software engineer in need of extra processing power or a heftier graphics card, an AiO probably won’t cut it for your needs. The limited amount of space in the case minimizes the ability of AiOs to cool their components, which restricts your ability to overclock your CPU, for example. If you’re looking to do any modern gaming, an AiO is not the best choice. Super computer supercomputer, any of a class of extremely powerful computers. The term is commonly applied to the fastest high-performance systems available at any given time. Such computers have been used primarily for scientific and engineering work requiring exceedingly high-speed computations. Common applications for supercomputers include testing mathematical models for complex physical phenomena or designs, such as climate and weather, evolution of the nuclear weapons and reactors, new chemical compounds (especially for pharmaceutical purposes), and cryptology. Embedded Computer Embedded computers are everywhere. They are in phones, microwaves, airplanes, automobiles, calculators. The list goes on and on. An embedded computer, which is an integral component of most embedded systems, is a combination of hardware and software that is designated to perform a highly specific function. For example, the type of embedded computer in a washing machine will not be the same as the embedded computer in a Nikon camera. Because the software in embedded computers is designed to only execute certain tasks, the computer’s software in one device can be totally distinct from that of another. Programs and Apps Computer Software: Computer software is set of programs and programs consist of many instructions. Without software hardware cannot be operated. There are three basic types of software: 1) System software: System software controls all the activities of hardware of computer system. It includes following. Operating System Software: Operating system software popularly known as operating system software is an interface between user and hardware. Programming language translator: This software converts code written inprogramming language to computer understandable binary language for example compliers. Communication Software: These software supports communication among computers in the network for example net meeting in windows OS. Utility programs: These are the programs which performs the maintenance work of the computer.  2) Application software: This software runs on system software. Basically, application software are created specifically for the user or tailored as per the user's requirement. There are two types of application software: Special Purpose Application Software: They are used to perform special task for example Tally is used by accounts for keeping all the accounting details. General Purpose Application Software: This software is used by many people for various tasks for example. ✓ MS-Office which include word processing, spreadsheet and database package ✓ Photoshop ✓ Turbo C ✓ Web browsers 3) Utility Software: Utility software is the software which performs the maintenance work like disk formatting, defragmentation or scanning computer from virus or any other purpose. It also includes file copying, memory dumping, sorting or merging, file maintenance etc. Technology uses Computers are almost useful in all areas. In fact in our everyday life it is used in almost every step. Few prominent areas where computers are used extensively are: 1. Airlines Booking Now one can book ticket for a flight leaving from New York while sitting in Melbourne. All the airlines are interconnected through computers. The same goes for Railway but it is restricted to individual countries only. 2. Business For most of the companies, all the work relating to accounts is now done on computers, for accuracy and speediness. A businessman can access their mails through internet while working in his own PC. 3. Banks Computer in banks have made it possible that one can get account information while sitting at home only. For this bank must use the facility of E Banking.Computer operated ATM machines are used to withdraw or deposit money from anywhere in the world. 4. Cinema Now a day's most of the film editing is done by computers. One can add and delete film clips at a snap using computer. In fact, some movies are totally made using computers. File like Toy Story is made using computers. 5. Cartoons There are various programs available in computers which allow the user to create animations by using multimedia tools. By learning about them one can become an expert animator. 6. DTP (Desktop Publishing) It has revolutionized how composing for printing used to done. Now every book for printing is composed on computer since it is very easy to edit and read on screen. 7. Defence Computer play important role in defence America was the first country to usethe computers in defence for pin pointing the position of enemy targets. Most of the missiles these days are computer controlled, 8.Education Computers are used in teaching also. In fact this book on computers was created using computers: Most of the schools now use computers for accounting, Student record management, Papers preparation and even result compilation. 9. Home Computer at home has become an addition entertainment media. One can use it for playing games, watching movies, listening to songs, writing letters, creating own database of friends etc. 10. Library Maintaining the records in library manually used to be a very cumbersome method. Computers have dramatically changed the way the cataloguing is done in libraries. 11. Medicine Lots of research in medicine is done using computers. Doctors now days can See the complete structure of the human body using the computers. 12. Space Technology Computers keep the track of all movements of the satellites and control them using computer operated measures. 13. Weather Using computers and satellites weather can be predicted for the next few days. In fact, the biggest computer in India is with the Meteorological Department of India at New Delhi. Technology Users: A home user is any person who spends time using technology at home. Parents, children, teenagers, grandparents, singles, couples, etc., are all examples of home users. A small/home office user includes employees of companies with fewer than 50 employees, as well as the self-employed who work from home. Small offices include local law practices, accounting offices, travel agencies, and florists. A mobile user includes any person who works with computers or mobile devices while away from a main office, home, or school. Examples of mobile users are sales representatives, real estate agents, insurance agents, meter readers, package delivery people, journalists, consultants, and students. A power user is a user who requires the capabilities of a powerful computer. Examples of power users include engineers, scientists, architects, desktop publishers, and graphic artists. enterprise user An enterprise has hundreds or thousands of employees or customers who work in or do business with offices across a region, the country, or the world Known as enterprise user. Servers A server is a computer on a network that manages network resources. It is a computer which provides connectivity to number of other computers. They allow client or terminal to access data from the server as per requirement. Server controls access to the software installed on it. A rack server, sometimes called a rack-mounted server, is a server that is housed in a slot (bay) on a metal frame (rack). A rack can contain multiple servers, each in a different bay. The rack is fastened in place to a flat surface. A blade server is a server in the form of a single circuit board, or blade. The individual blades insert in a blade server chassis that can hold many blades. Like a rack server, the chassis is fastened in place to a flat surface. A tower server is a server built into an upright cabinet (tower) that stands alone. The tower can be similar in size and shape to a desktop tower or larger.  What is input? Any information or data sent to a computer for processing is considered input. Input or user input is sent to a computer using an input device. The picture is an illustration of the difference between input and output. The input example (top) shows data sent from a keyboard to a computer. Devices commonly used to provide input to a computer include: Keyboard, pointing devices (Mouse, Trackball, Touchpad) Pen Input (Stylus, Digital pen, Graphic tablet) Voice Input, Scanners and Reading Devices (Optical Scanners, Optical Readers, Bar code Readers, RFID Readers, Magnetic stripe Readers, MICR Readers) Keyboard The keyboard is one of the earliest and the most commonly used input device for entering data and commands into the computer system. A keyboard is a collection of different switches or keys. Each key has a different code/character associated with it. Some represent alphabets, digits and symbols whereas some keys riper Sent non-printable characters and are responsible for specific operation. arranged Keyboard Layout: The most commonly used keyboard is the IBM-101 keyboard. The keys are in different groups as follows. (1) Alphanumeric Keypad: This set contains alphabetic, numeric and special characters. (2)Numeric Keypad:- This set of keys act as numeric key s when Numlock is ON and act as cursor movement keys when Numlock is OFF. (3)Cursor Movement Keys:- The four keys (up, down, left and right arrow keys) are used for moving the cursor to a desired location. (4)Function Keys: The 12 keys F1 to F12 represent an operation. The purpose of each key depends on the application being used. (5)Special Purpose Keys: These keys perform specialized functions.They are Esc, Pause, Insert, Delete, etc. (6) Modifier Keys: They are used to modify the input of other keys. They are used by holding down the modifier key while pressing another. They are Shift, Ctrl and Alt. Process of accepting Input from the keyboard: (1) When a key is pressed, a computer circuit called keyboard controller puts a code (scan code of the key) into a memory called keyboard buffer. (2) The keyboard controller signals the computer's system software that key has been pressed by sending an interrupt request. (3) The system software then reads the keyboard buffer and send the keys scan mode to the CPU.  Pointing devices 1) Mouse: This is one of the most popular and effective pointing devices for GUI applications. It allows the user to move a cursor or pointer on the screen to any desired location. The user can use mouse for drawing or painting The operations can be performed using a mouse in two steps: (i) Pointing (ii) Clicking, double-Clicking. Dragging or Right-clicking the buttons, which are on the mouse. These points are explained below: Clicking: Pointing to an item and quickly pressing and releasing the mouse button are called as clicking. Left clicking: Clicking the left button while the pointer is over something on the screen will select it. Right Clicking: Clicking the right button while the pointer is over something on the screen will bring up a menu of options. This menu list things that can be done with that object (example: copy and paste) Double clicking: Double-clicking means clocking twice with your left mouse button very fast. This is used to being programs. Dragging: Holding down the mouse button while over an object will grab on to it. If you move the mouse while holding down the mouse button you will be able to move (Drag) the object to a new place on the screen. Dropping: After dragging an item, releasing the mouse button will leave (drop) the object at the new place on the screen. Types of Mouses: (i) Mechanical Mouse: The mouse has a ball on its underside, which rolls when the mouse a flat surface. There are two rollers, which are placed at 90° to each other. One roller responds to the vertical movements and other to the horizontal movements. These rollers are attached to a wheel which spins as the roller rill and relays information about how much each roller spins. The information is sent in the form of electrical signals by the cord attached to the mouse. The electrical signals are created either by using an opto mechanical method consisting of LED and light sensor or by using metal contact which generate electrical signals when the wheel spins. This electrical signal is then converted into the corresponding mouse position on the screen. (ii) Optical Mouse: Optical mouse does not have a ball and wheel arrangement. It uses a small LED that bounces light off the flat surface. This light is detected by a CMOS sensor which sends signals to a Digital Signal Processor (DSP). The DSP compares the Previous images with the current to measure movement. It then sends the corresponding coordinates to the computer, which then moves the cursor on the screen. This mouse does not have any moving parts and hence there is less wear and tear. It is capable of higher resolution but is expensive. (iii) Wireless Mouse: This can either be a mechanical or optical mouse except that it does not have a cord. It is powered by batteries and sends information to the computer using radio or infrared signals. These signals are detected by an infrared detector or receiver, which is connected to the computer. Advantage: Mouse moves cursor around the screen faster than using keystrokes Disadvantages: Require moving hand from keyboard to mouse and back. Repeated motion can lead to carpal tunnel syndrome. 2) Trackball: Trackball is a ball inserted in a small external box adjacent to and in the same unit as the keyboard of some notebook computers (laptops). It is like an upside-down mouse. Instead of moving the whole mouse around, the user rolls the trackball (which is on the top or side) with fingers to move the graphic cursor (As the electronic circuitry detects the direction and speed of the spin and passes the information to the processor). One or more buttons for choosing various options are incorporated in the design of the trackball. Advantages: ✓ It does not require as much desk space as a mouse. ✓ It is not as tiring since less motion is needed. Disadvantages: ▪ It requires fine control of the ball with just one finger or thumb. ▪ A repeated motion of the same muscles is tiring and can cause carpal tunnel syndrome. 3) Touchpad: Touch pad is a pointing device works same as mouse. Like mouse it contains two keys which work same as left and right button of mouse. It moves pointer on the screen and allows selection of any option or icon. It is small, flat, rectangular device. They are mostly available on laptop computers. External touch pads and keyboards with built-in touch pads are available for use with desktop computers also. ❖ Pen Input 1) Light Pen (Digital pen)  Light Pen is a picking device used with hand-held computers and digital assistants. This pen-like device (also called stylus) is held in the hand and used to write on a special pad or directly on the screen. It can also be used like a mouse for selecting commands. Pen base computers are not generally used to enter large amount of text but are used for selection of a menu or icon, inputting signatures or messages. 2) Graphic tablet A graphics tablet also referred to as a digitizer, digital graphic tablet, pen tablet, drawing tablet, external drawing pad, or digital art board, is a computer input tool that enables users to manually draw images, animations, and graphics using a special pen-like stylus. It is much like how someone would draw with a pencil and paper. Data entry or handwritten signatures may also be captured using these tablets. It can also be utilized to copy an image from paper that has been taped or otherwise fixed to the tablet's surface. Digitizing is the process of capturing data in this manner, which involves tracing or inputting the corners of linear polylines or geometric objects. ❖ Voice Input Voice input is used to enter data and instruction into the computer instead of using keyboard for entering data. A hardware-and-software combination used to input spoken words and convert them to digital form is known as a voice-input system. All voice-input systems consist of a microphone or headset. Microphone is used to speak into the system which a stand- alone device can be attached to the computer. The spoken words are displayed on the screen. Voice-input capabilities are also increasingly being incorporated into both desktop and portable PC operating systems. Sometimes internet telephony is also used to communicate over internet through voice. Voice input can be recorded to be sent via e-mail or used in a multimedia presentation. Scanners and Reading Devices ❖ Optical Scanners: Optical Scanners are input devices which are capable of entering information directly into the computer. The main advantage of direct entry of information is that users do not have to type the information. This provides faster and more accurate data entry. A scanner is an input device that translates paper documents into an electronic format that can be stored in a computer. The input documents may be typed text, pictures, even handwritten material. This input device has been found to be very useful in preserving paper documents in electronic form. The copy of a document stored in a computer in this manner will never deteriorate in quality or become yellow with age and can be displayed or printed whenever desire The scanner treats the document as if it is drawn on a graph sheet. An intersection of a horizontal and a vertical line of the graph are called a grid point. If there is a dark spot at the grid point, it is represented by '1' otherwise it is represented by '0'. This representation is called the bit map representation of an image. Each bit in the representation of the image is called a "Pixel". Scanners having 300 to 600 grid points per inch are common. For example, a good quality black and white scanner may use 4 bits per grid point. Similarly, a colour scanner may use 24 bits per grid point to represent a maximum of 256 different shades of colour. Scanners come in various shapes and sizes. The two commonly used types based on this classification are flat-bed and hand-held scanners. They are briefly described below: Types of Scanners: (i) Flat-bed scanner: A flat-bed scanner is like a photocopy machine consisting of a box having a glass plate on its top and a lid that covers the glass plate. The document to be scanned is placed upside down on the glass plate. The light source is situated below the glass plate and moves horizontally from left to right when activated. After scanning one line the light-beam moves down a little and scans the next line. The process is repeated for all the lines. It takes about 20 seconds to scan a document of size 21 cm x 28 cm. (ii) Hand-held scanner: Hand held scanner has a set of light emitting diodes encased in a small case that can be conveniently held in hand during operation. To scan a document, the scanner is slowly dragged from one end of the document to its other end with its light on. The Scanner has to be dragged very steadily and carefully over the document; otherwise the conversion of the document into its equivalent bit map will not be correct.  Due to this reason hand-held scanners are used only in case where high accuracy is not needed. They are also used when the volume of documents to be scanned is low. They are also much cheaper as compared to flat-bed scanners. ❖ Optical readers i) OCR (Optical Character reader) Optical Character Recognition (OCR) is the process that converts an image of text into a machine- readable text format. For example, if you scan a form or a receipt, your computer saves the scan as an image file. You cannot use a text editor to edit, search, or count the words in the image file. However, you can use OCR to convert the image into a text document with its contents stored as text data. OCR also employs a set of printing characters with standard font that can be read by both human and machine readers. The machine reading is done by light scanning techniques in which each character is illuminated by a light source and the reflected image of the character is analysed in terms of the light-dark pattern. OCR has the potential of reading even handwritten documents straightway. Optical Character readers can read upper and lower case letters, numeric and certain special characters from handwritten, typed and printed paper documents. The specific characters that can be read and whether the characters must be handwritten, typed or printed depend upon the type of OCR being used. Obviously OCR time consuming step of transcription. They can read the characters printed by computer printer, cash registers and typewriters. Some readers can also read hand-written documents. Advantages of OCR: Cheaper than paying someone to manually enter large amounts of text. Much faster than someone manually entering large amounts of text. Disadvantages of OCR: Not 100% accurate, there are likely to be some mistakes made during the process. All documents need to be checked over carefully and then manually corrected If the original document is of poor quality or the handwriting difficult to read, more mistakes will occur. Not worth doing for small amounts of text. Most optical readers are not economically feasible unless the daily volume of transactions is relatively high. However, further developments in OCR are likely to make optical readers much cheaper. ii) Barcode readers Bar Coding is a method of printing bars of varying thickness and spacing. They are printed on items like books, packages, etc. The bar codes provide information like manufacturer, produce code, price, etc. A sample bar code is as follows.  In order to read the bar code, a bar code scanner has to be used. This scanner consists of an optical device which analyses the bars for width and spacing and converts this information into electrical pulses for the computer. The bar code reader emits a beam of light frequently a laser beam that is reflected by the bars. A detector detects the reflected light and generates corresponding electrical pulses. Many retail outlets use barcodes for keeping the track of items and retrieving the details when required. Bar code scanners are to two types (i) Hand Held Scanner: The bar code reader is held in the hand and moved over the bar code image. It is mainly used by courier and delivery agents. (ii) Flat Bed Scanner: The flatbed model is most commonly used in supermarkets and departmental stores. The products are placed over the flat rectangular scanner surface with the bar code image in contact with the surface. The standard coding convention used is the Universal Product Code (UPC). After the reader has identified the bar code, it covers the individual bar patterns into numeric digits iii) RFID Reader: Radio-frequency identification (RFID) is a technology that uses communication through the use of radio waves to transfer data between a reader and an electronic tag attached to an object for the purpose of identification and tracking. Most RFID contain at least two parts: one is an integrated circuit for storing and processing information a radio-frequency (RF) signal, and other specialized functions, the other is an antenna for receiving and transmitting the signal. RFID tags can have different sizes and shapes. It may be in form of labels and cards. RFID is also used in air baggage, employee word robes, tracking vehicles pass through toll way system etc. IV) Magnetic Stripe Card Reader: A magnetic stripe reader, also called a magstripe reader, is a hardware device that reads the information encoded in the magnetic stripe located on the back of a plastic badge. Magnetic stripe technology is everywhere. We use cards with magnetic stripes on them every day without even thinking about it. The technology has been with us for many years, but there are still many new things going on in the industry. A magnetic stripe is the black or brown stripe that you see on your credit card, or may be the back of your airline ticket or transit card. The stripe is made up of tiny magnetic particles in a resin. The particles are either applied directly to the card or made into a stripe on a plastic backing which is applied to the card. The magnetic stripe consists of three horizontal lines including the information about identification of user and card issuer. Sometimes it may contain user's name expiration date etc. account number, expiration date etc. V) MICR: In this method, human readable characters are printed on documents using special magnetic ink. A magnetic ink character reader can recognize these character characters, The MICR devices used the EBB font, which contains digits 0.9 and 4 special symbols as shown in figure. MICR is especially used in banking. A bank cheque contains branch code, cheque number and account number pre-printed in magnetic disk. The MICR reader can read data directly from the cheque into the computer system. This eliminates manual data entry and ensures accurate data entry. Advantages of MICR: ✓ MCIR possesses a very high reading accuracy. Cheques may be smeared,stamped, roughly handled yet they are accurately read.  ✓ Cheques can be handled directly without transcribing them on floppy disk, magnetic tape etc. ✓ Cheques can be read both by human beings and machines. Disadvantages of MICR: ✓ MICR has not found much favour from business. ✓ Damaged documents, cheques not encoded with amount etc. have still to be clerically processed. What is Output? Any information processed by and sent out from a computer or other electronic device is considered output. Output devices Output devices are used to transfer information stored in the computer or the result of any processing done to the outside world. There are several types of output devices manufactured for this purpose, but the most commonly used devices are the video monitors and printers. Printers provide a printed record on paper, for permanent use. Display Devices: This is the most commonly used output device on most personal computers. It is also called as Visual Display Unit (VDU) or Cathode Ray Tube (CRT) display. Monitors used with PC's are of two types: (i) CRT monitors (ii) Flat-Panel monitors (LCD monitors) used with portable computers. Monitors can also be (1) Monochrome: Display only one color against a contrasting background. (2) Grayscale: Display varying intensities of grey against white background. (3) Color: Display from 16 colors to 16 million colors. Monitor (Display screen): A monitor can be considered as a window into the computer's memory. It allows data entry to be checked by echoing input characters on the screen. The disadvantage of monitors is that data on the screen is temporary (called softcopy) and they can hold only limited amount of data. These days monitors come in various sizes. The type of monitor to be used depends upon the use of computer. Quality Factor - Resolution Resolution defines sharpness and clarity of an image and is specified as the number of dots per character. Modern packages are using a lot of graphics and therefore require high resolution monitors. Display quality: Adaptors are cards installed in motherboard to control a monitor. The following specifications were evolving over the years. Hercules - mono ✓ Colour Graphics Adaptor (CGA) - low quality ✓ Enhanced Graphics Adaptor (EGA) - medium quality ✓ Video Graphics Array (VGA and Super VGA) - high quality ✓ Extended Graphics Array (XGA) - successor of SVGA, has the power to handle the Video and animation requirements of the modern multimedia packages and games Printers A printer is a peripheral output device designed to get a hard copy of the output. Printers are of two types. Features of Printers: (i) Image quality: It is measured in dots per inch (dpi), more the dpi the better is the image. (ii) Speed: It is measured in pages per minute (ppm). Different printers’ different ppm. (iii) Cost: The cost depends upon the resolution, technique used for printing, colour or black and white etc. Laser printers are the most expensive. (iv) Operational cost: This determines the cost of printing a page (which depends upon the cost of ink cartridges). Non-Impact Printers: Do not use the impact technique but use spray technique or use heat method to form an image on paper. Non-impact printers include laser printers and ink-jet printers. The important difference between impact and non-impact printers is that impact printers are much noisier but are useful for making multiple copies like carbon copies. Ink-Jet Printers: These are non-impact printers, which create an image directly on paper by spraying ink through tiny nozzles. The core of inkjet printer is the print head, which contains tiny nozzles to spray drops of ink. It is attached to an ink cartridge (s) such as separate black and color cartridge or both in a single cartridge. The cartridges of some inkjet printers include the print head itself. The cartridge has an ink reservoir, which has one or more nozzles. The ink jet through the nozzles is guided by electrically charged plates, which control the direction of the spray. Colour inkjet printers have four nozzles (cyan, magenta, yellow, and black). Features: (i) Inkjet printers generate very good quality and high resolution prints. (ii) They are extensively used for printing graphics. (iii) The resolution is about 360 dpi. (iv) Speed is about 2 to 4 ppm. (v) Initial cost is less but operational cost is high as compared printers Example: Hewlet-Packard Deskjet, Canon. Impact Printers: Create an image by pressing an ink ribbon against the pins or hammers. Impact printers include all printers that work by striking an ink ribbon. Daisy wheel, dot matrix, and line printers are impact printers. Dot-matrix: It is an impact printer most commonly used in offices etc. where physical impact with the paper is important, such as when the document has carbon-copies. Mechanism: It has a print head, which contains a matrix of pins arranged in one or more columns. It may contains 9 pins or 24 pins. Depending upon the character or image to be created, the CPU gives instructions to the printer to activate certain pins of the print head. These pins are pushed out in various combinations. When they strike the ink ribbon, the ink is transferred onto the paper. The image is in the form of dots and hence the name - dot matrix. The print head keeps moving left to right line-by-line in synchronization by a roller-feed mechanism, which moves up the paper line by line. These printers have a speed of about 50 cps to 500 cps (Characters per second) However, they are noisy and print quality is not very good. Since their cost less, they are widely used for daily and bulky printing jobs. Advantages: ✓ Dot matrix printers, like any impact printer, can print on multi-part stationery or make carbon- copies.  ✓ Impact printers have one of the lowest printing costs per page. As the ink is running out, the printout gradually fades rather than suddenly stopping partway through a job. They are able to use continuous paper rather than requiring individual sheets, making them useful for data logging. ✓ They are good, reliable workhorses ideal for use in situations where printed content is more important than quality. The ink ribbon also does not easily dry out, including both the ribbon stored in the casing as well as the portion that is stretched in front of the print head; this unique property allows the dot-matrix printer to be used in environments where printer duty can be rare, for instance, as with a Fire Alarm Control Panel's output. Disadvantages: ✓ Impact printers are usually noisy, to the extent that sound dampening enclosures are available for use in quiet environments. ✓ They can only print low resolution graphics, with limited color performance, limited quality and comparatively low speed. While they support fanfold paper with tractor holes, single-sheet paper usually has to be wound in and aligned by hand, which is relatively inconvenient and time-consuming. ✓ While far better suited to printing on labels than a laser printer or an inkjet printer, they are prone to bent pins (and therefore a destroyed print head) caused by printing a character half-on and half- off the label, for text-only labels (ie. mailing labels), a daisy wheel printer offers most of the advantages of a dot matrix, with better print quality and a lesser chance of being damaged. Data Projectors A device that projects computer and TV output onto a white or silver fabric screen that is wall, ceiling or tripod mounted. Data projectors are widely used in classrooms and auditoriums for instruction and slide presentations. LCD Projectors An LCD projector is a type of projector based on liquid crystal displays which can display images, data or video. An LCD projector works on transmissive technology. LCD projectors are more popular than many alternatives due to the fact that they are cheaper to produce and have excellent color reproduction. They are commonly used in business meetings, presentations and seminars. There are several advantages of using an LCD projector. Higher lumen output can be delivered by an LCD projector at a lower cost compared to a digital light processing (DLP) projector. It can also provide greater brightness with lower energy consumption. Unlike DLP projectors, LCD projectors do not suffer from rainbow effects and dithering. Another salient feature of LCD projectors is their image sharpness and providing greater zoom magnification. However, there are certain disadvantages associated with LCD projectors. They can be comparatively bulkier than other projectors, with lesser portability. The LCD panels have a limited lifetime, they do not have high contrast, and may suffer from black and dead pixels. Maintenance can be higher in the case of LCD projectors when compared with other projectors. If an LCD projector is used frequently over a long period of time, image degradation is possible, and they also heat up more quickly than DLP projectors. DLP projector  Digital Light Processing (DLP) is a video technology created by Texas Instruments that is used for front and rear projection units. DLP technology is common for rear projection in TVs and it is also used in front projectors for units designed for businesses and classrooms. Presently, DLP comes in two major forms: 1-chip DLP and 3- chip DLP. Digital Light Processing makes use of micromirrors, called a Digital Micromirror Device, to reflect light and color onto a screen. These micromirrors are positioned in a semiconductor chip and are very small. Generally, a micromirror pitch may measure less than 5.4μm. Each of these mirrors projects one or more pixels in the image. The number of mirrors generally correspond to the resolution of the projected image. The movement of the mirrors allows the DLP device to create colors and gray shades that can form video images. All DLP chips are produced by Texas Instruments. Motherboard A motherboard is the most important part of the computer. It is also called a system board it is the main circuit board of computer. The circuit for the processer, memory and other components are there on the computer chip. The computer chip is a small piece of semiconducting material, on which IC are attached it is a generally made of silicon. The integrated circuit is used for carrying electrical current. It contains many elements like capacitors, resistors, transistors. A transistor is used to open and close the circuit for electrical charges. A capacitor is CC-101 Computer and Emerging Technologies used to hold or store an electric charge. A resistor is a component used to reduce the current flow. Processors: A processor is also called Central Processing Unit (CPU), It is also called a brain of computer. It carries and interprets the basic instructions to operate a computer. A processor can be either single core or multi core. Single core processor uses only a single chip while multi core processor has two or more separate processor cores.  A processor contains Control Unit (CU) and arithmetic and Logic Unit (ALU). The control unit is the component that directs and coordinates most of the operations like interprets each instruction and executes it in a memory. The multiplication and division. Also it performs comparison operations. ALU performs basic arithmetic operations like addition, subtraction, multiplication and division. Also it performs comparison operations. Difference between Single core processor & multicore processor Single core processor Multicore processor It uses single chip and a single processor core It uses a single chip but two or more separate to perform functions. processor cores to perform functions Performance is low. Increase performance Consumes more power Consumes less power Emitting more heat inside the case Emitting less heat inside the case Less energy efficient Less energy efficient Machine Cycle For each instruction, processor repeats a set of four operations: 1) Fetching 2) Decoding 3) Executing 4) Storing. Figure: 2.3 CPU Machine Cycle  1) Fetching: It is used to fetch (obtain) program instruction or data from memory. 2) Decoding: It is used to translate the instruction into computer understandable signals. 3) Executing: It is used to carry out the commands and performing the operation. 4) Storing: It is used to write the result into memory. Registers: Processors contain high speed storage locations called registers which are used to hold data and instruction. It is a part of processor. There are different types of registers like Accumulator (AC). Data Register (DR). Address Register (AR). Program Counter (PC), Memory Buffer Register (MBR), Memory Data Register (MDR) and Index Register (IR). It performs functions like storing location of fetched instruction, storing instruction and data as well as result of the instruction. System Clock: A processor is based on a small crystal circuit called system clock that is used to control timing of computer operations. Each tick of a system clock equates to a clock cycle. Today's processors can execute more than one instruction per clock cycle. The number of ticks per second is called the clock speed of the system clock. It is measured in Gigahertz (GHz). When the clock speed is faster, the processor can execute more instructions per second. Processor Cooling: Processor chip for servers, desktops or other computer devices generate a heat. It is required to maintain cooling of the processor. There are three types of mechanisms used for processor cooling Heat sink fan Liquid Fluid Cooling pad Memory It is a component used to store instructions waiting to be executed by processor and results of processed data. It also stores operating system and other programs, applications and data as well as resulting information. A byte is the basic storage in memory. Each byte has an address which is used to identify the location in memory. Common sizes of memory are in Gigabytes (GB) or Terabytes (TB). 1 GB 1 Billion bytes 1 TB 1 Trillion bytes approximately. Types of Memory Volatile Memory: When computer's power is turned off, it loses its contents. It is also called a temporary memory. There are two types of volatile memory. RAM Cache memory RAM (Random Access Memory): It is also called main memory or primary memory. It has memory chips that can be read from or write to by the CPU and other devices. When computer's power turned on, some operating system files load into RAM from storage device and remains in RAM as long as the power is on. There are two types of RAM: SRAM (Static Random Access Memory): SRAM chips are faster than DRAM chips. These chips do not have to be periodically Refreshed. It is more expensive. It is used for CPU cache. It uses 4 to 6 transistors to store data and instructions, DRAM (Dynamic Random Access Memory): DRAM chips must be re-energized that means they have to be periodically refreshed otherwise they lose its contents. So, it has more complicated circuits. It is faster and less expensive. It is used in main memory. It uses only I transistor and a capacitor.  Difference between SRAM and DRAM Cache Memory: It is also a temporary memory. It is used to store frequently used instructions and data. It is faster, expensive and has lesser access time. Generally, it is placed between CPU and a main memory. Its capacity is low than RAM. There are two types of cache: Memory cache Disk cache Memory cache: It is a type of cache that is a part of computer's main memory RAM. It is also called memory buffer. There are three types of memory cache. L1 cache (Primary cache): The size of L1 cache is very small like 2 KB to 64 KB. It is embedded on computer’s processor. L2 cache (Secondary cache): CC-101 Computer and Emerging Technologies The size of L2 cache is more than LI like 256 KB to 512 KB. If the instruction is not found in LI than it searches into 12 by microprocessor. It is located on microprocessor. It is slower than LI. L3 cache (Main memory): It is larger in size like 1 MB to 8 MB but slower in speed than Li and 1.2 cache embedded on the motherboard. Disk Cache: It improves time it takes to read from or write to a hard disk. It is also a specified portion of RAM. Non-volatile memory: Non-volatile memory doesn't lose its contents when computer's power turned off. It is also called permanent as well as secondary memory. There are three types of non- volatile memory. ✓ ROM ✓ Flash memory ✓ CMOS ROM (Read Only Memory): It is a type of non-volatile memory means the contents is not lost when the computer's power turned off. It is used for permanent storage of data. The data can't be modified which is stored on ROM chips, so it is read only. There are various types of ROM: PROM (Programmable Read Only Memory): It is a type of ROM in which user can perform write operation only once. This type of ROM can't be modified once it is written. So, it is also called WORM (Write Once Read Many) EPROM (Erasable Programmable Read Only Memory): It is a type of ROM in which user can perform read and write operation both. In this type of ROM, data can be erased and new data can be written also. EEPROM (Electrically Erasable Programmable Read Only Memory): It is a type of ROM which functions same as the EPROM with only one difference. The data is erased using ultraviolet light (electrically) and re-written. Flash Memory: It is an electronic non-volatile memory that can be electrically erased and reprogrammed. It is often found in USB flash drives, media players, and digital cameras and solid-state drives. It is less expensive than EEPROM. It does not require batteries for storage. It has a fast access time. CMOS (Complementary Metal Oxide Semiconductor):  It is a small amount of memory on computer's motherboard that stores BIOS settings. It consumes less power and provides high speed. It uses a battery power to save information. The flash memory chips are often use CMOS technology. Storage Storage Capacity Storage capacity refers to how much disk space one or more storage devices provides. It measures how much data a computer system may contain. For an example, a computer with a 500GB hard drive has a storage capacity of 500 gigabytes. Storage Access Times Access time is total time it takes a computer to request data, and then that request to be met. A good analogy is the time between you ordering a pizza and it being delivered. Access time pertains to devices such as memory, hard drive, CD-ROM (compact disc read-only memory) or other mechanisms. Computer access time is commonly measured in nanoseconds or milliseconds and the lower the time the, better or faster the computer should perform. Difference between Memory and Storage Memories are made up of registers. Memory locations are identified using Address. The total number of bit a memory can store is its capacity. Memory is a vital component of a computer system, as it allows the computer to store and access data quickly and efficiently. Memory is of three type: 1. Primary Memory: Also known as main memory or internal memory, primary memory is the memory that a computer uses to store data temporarily while the CPU is processing it. The two main types of primary memory are Random Access Memory (RAM) and Read-Only Memory (ROM). 2. Secondary Memory: Secondary memory refers to external storage devices that can be used to store data for long-term use, even when the computer is turned off. Examples of secondary memory include hard disk drives (HDDs), solid-state drives (SSDs), USB flash drives, and memory cards. 3. Cache Memory: Cache memory is a small amount of memory that a computer uses to store frequently accessed data for quick retrieval. It acts as a buffer between the CPU and main memory, helping to speed up data access times. Cache memory is typically built into the CPU or located on a separate chip on the motherboard. Storage: Storage allows you to store and access data on a long-term basis. Data remains the same and nothing changes in the hard disk drive: everything gets pulled off into the main memory. Storage allows you to access and store your applications, operating system and files for an indefinite period of time. Storage devices can be classified into two categories: Internal storage and external storage. Internal storage devices are located within the computer, such as the hard drive, solid-state drive, or flash memory. External storage devices, on the other hand, are connected to the computer via an external port, such as a USB or Thunderbolt port.  Storage is a way to store data, information, program and application. When we input some data in a computer and get output from it, the data and information is stored in the storage medium. A storage device is a hardware that stores and retrieves data to and from the storage medium. The process of transferring data and information from memory to storage medium is called writing process. The process of transferring data and information from storage medium to memory is called reading process. There are many storage mediums like hard disk, solid state drives (SSD), memory cards, USB flash drives, optical discs, smart cards, RFID tags, NFS tags etc. The storage has capacity means number of bytes it can store. The data on a storage medium is non-volatile means permanent. The speed of storage devices and memory is defined by its access time. Access time is a) the amount of time it takes a storage device to store the data on a medium as well as b) time required to deliver the data from memory to processor. Storage device also has a transfer rate which is the speed to transfer data and information to and from a device. i) Hard Drives: It is a non-volatile memory hardware device that permanently stores and retrieves data on a computer. It is a secondary storage device: Hard drives can be either internal or external. Internal hard drives are built-in the computer system while external hard drives are attached to computer via cable or USB port. Hard drives are collection of Hard disk and SSD (Solid State Drives) ii) Hard Disk: It is an electro-mechanical data storage device that uses magnetic storage to store and retrieve data. It contains one or more circular platters to store data and information. It is a type of non- volatile storage. The hard disk is enclosed in a sealed case to protect it from external dust.  The hard disk is composed of number of platters, read/write head, actuator, arm and spindle. Platters: A platter is a glass, ceramic or aluminium material that has a thin coating which allows data to be stored magnetically on its surface. A hard disk has multiple platters stored on the top of one another. Read/write head: Each platter has 2 read write head one on each side that reads and writes data to and from the platter. Actuator: The actuator is used to move read/write head to the proper location on platters. Spindle: The spindle is used to hold as well as rotate the platters at a particular rpm (revolution per minute). Each platter on a hard disk is divided into number of tracks and sectors Track: A platter is divided into thin, concentric bands which is circular path or surface of a disk. Sector: Each track is further subdivided into number of sectors which is a pie-shaped section on which data is stored. Each sector can hold more than 512 bytes of data. Cluster: Sectors are often grouped together to form a cluster. III) SSD (Solid State Drives): It is a storage device that uses Integrated Circuit (IC) assemblies as memory to store data. It stores data on flash memory. It has its own processor to manage its storage. It is also called Solid State Device or Solid State Disk. SSDs are more resistant to physical shock and have quicker access time and latency. They can be directly installed on motherboard or adapter card. They are available in variety of factors like 1.8, 2.5 or 3.5 inches.  Advantages: It has faster access time. It consumes less power. t generates no noise, as it doesn't have moving parts: It generates less heat. It has more lifespan. It is light weight. It is not affected by magnetism. Disadvantages: It is more expensive than hard disk. It has lower storage capacity. The data recovery becomes complex in case of failure. Poor availability than hard disk. IV) External Hard Drives: It is a storage device that is located outside of a computer, It is connected thr USB cable or it can be wireless. It is a portable storage device that is used t media file and other files that a user needs to carry. It has a high storage c compared to flash drives. It is also called removable hard drives. External hard Drives are also enclosed in a sealed, airtight case. Generally it I used to trans from one computer to another computer. Advantages: It is less expensive. Easy to install and configure. More storage space. Easy to access(Connect & disconnect) It is portable Disadvantages: It can break easily. Overheating problem because there is no cooling fan in external hard drives. Stolen easily  Exterior cabling and power adapter is required. V) RAID (Redundant Array of Independent Disks) It is a data storage technology that combines multiple physical disk drive components into one or more logical units. It acts like a single large hard disk. Therefore, a group of two or more integrated hard drives is called a RAID. It is a technology in which two or more hard disks are integrated. It is a type of hard drive system in which smaller drives are connected into a single unit that acts like a single large hard drive. RAID uses concept of mirroring and striping. Mirroring means to write data on two drives at a time to store copy of it (Redundant data), Striping means to split data and information into multiple drives in the array. But striping doesn't provide redundant data. RAID storage is expensive but more reliable. Advantages: It improves performance. Data recovery is easy Increases data avaibility. It increases computer's speed. It is used for data backup It improves throughput. Easy to implement technology. Disadvantages: It is not used for mission critical system. It is not fault tolerance. (If one drive fails then all data lost from the array) VII) Portable Flash Memory Storage: It is a secondary storage medium used to store data. It is portable and can be easily carried from one place to another. Flash memory storage includes memory cards and USB flash drives Memory cards: It is portable memory storage. It is used to transport media files like music, video, photos and other files to and from mobile device and computer. It is a removable storage device. Memory cards are commonly used in portable electronic devices like digital camera, mobile phones, laptop computers, tablets, PDAs, media players, video game consoles etc.  A card reader/writer is used to read and write data on the memory computer doesn't have built- in card slot. USB Flash Drives: It is a non-volatile storage device that plugs in a USB port in a computer device. It is also called thumb drive or pen drive. It is removable, rewritable and smaller than optical disc. They are used for data storage: data back up and transfer of files. They are very light weight, smaller and easily portable. The capacity of USB flash drive varies based on user requirement. Advantages: It is small and light weight It consumes little power It has no moving parts Data can be retained for long period It doesn't require batteries or external power supply Disadvantages Data leakage because it is portable and hard to track Security breach due to malware can occur when the device is plugged into an infected. VIII) Optical Discs: It is usually a flat, circular disc which encodes data on a special material on one of its surfaces. It is a portable disc made up of plastic, metal or lacquer. The data can be read and write by a laser diode which spins the disc at the speed of about 200 to 4000 rpm or more. One side of the disc contains data which is coated by a transparent material while the reverse side of the disc usually has a printed label onto it. When user inserts the disc form of music or video, Optical discs are between 7.6 to 30cm in diameter. The most into the drive, the operating system automatically runs program stored on a disc in a common size of it is 4.75 inches. Optical discs are most commonly used for storing music, video or data and programs for personal computer. It stores data on the form of pits (Binary value of 0) and lands (binary value of 1). There are various types of optical discs: CD DVD Blu-ray CD (Compact Disc): It is a digital optical disc data storage format. CDs are used to store data so that it may be retrieved or executed for the later use. It can store software programs that can be loaded onto computer. There are three types of Compact disc.  CD-ROM (Compact Disc Read Only Memory): It is an optical disc which contains audio or software data that is read only. Manufacturers write data on CD and after that distributes to the consumers. In this type of optical disc, user can't write or erase data. It is a single session disc because manufacturers write data at a time. CD-R (Compact Disc Recordable): It is an optical disc in which user can write their own data in a form of audio, video, graphics or any file. User can't erase data on this type of CD. It is a multisession disc because user can write more data if space is available on it. This type of CD is also called WORM (Write Once Read Many). CD-RW (Compact Disc Rewritable): It is a multisession disc in which user can write data many times as well as erase data. It is also called Compact Disc Read/Write. IX) DVD (Digital Versatile Disc): It is an optical disc storage used to store any kind of digital data. It is widely used for software and other computer files as well as video programs. It provides more storage capacity than CD. Some DVDs are double sided also. DVD has three basic formats: DVD-ROM (Digital Versatile Disc Read Only Memory): In this type of Optical Disk manufactures write data at a time then distributes it to the users.So DVD-ROM allows users only to read data, users can't write or erase data from it. Example Movie DVD DVD-R and DVD+R (Digital Versatile Disc Recordable) In this type of optical disc, users can write data but can't erase it. It is multisession disc allows user to write its own data. Example: Photos DVD DVD-RW and DVD+RW and DVD-RAM (Digital Versatile Disc Rewritable): It is an optical disc in which data can be recorded and erased many time. It is a multisession disc X) Blu-ray disc: It is an optical storage capable of storing HD and ultra HD resolution videos. The name Blu-ray refers to the blue laser used to read the disc which allows information to be stored at greater density than DVD. Its storage capacity is high than CD and DVD. But it is also expensive than CD and DVD. The storage capacity of Blu-ray disc is from 25 GB to 50 GB. XI) Enterprise Storage: It is a centralized repository for business information that provides common data management, protection, and data sharing function through connections to computer system. It includes levels of redundancies so whenever one component fails, the other can be used. Enterprise storage includes RAID, NAS and SAN, magnetic tape etc. RAID Enterprise NAS SAN storage Tape RAID (Redundant Array of Independent Disk): It is a technology in which two or more hard disks are integrated. It is a type of hard drive system in which smaller drives are connected into a single unit that acts like a single large hard drive. RAID uses concept of mirroring and striping Mirroring means to write data on two drives at a time to store copy of it (Redundant data). Striping means to split data and information into multiple drives in the array, but striping doesn't provide redundant data. RAID storage is expensive but more reliable. NAS (Network Attached Storage): It is a hardware device that allows multiple client devices and users to access data from central disk storage. NAS has its own IP address as well as hard drive. NAS provides ease of access. The capacity of NAS high as well as it is less expensive. SAN (Storage Area Network): It is a high performance network dedicated to storage that is independent of common U network. SAN is combination of various storage devices. Advantages: ✓ Management of storage is easy ✓ Ease of access ✓ Sharing of storage is easy Used in disaster recovery ✓ Provides isolation from other servers ✓ Reliable backup and restoration ✓ Highly available Magnetic tape: It was the oldest storage medium used by enterprise storage to store data and information. It is a device coated with plastic ribbon used to store data. Data on a tape can be read and write by the tape drive. It is a low-cost storage medium. Cloud Storage Cloud storage is a service model in which data is transmitted and stored on remote storage systems, where it is maintained, managed, backed up and made available to users over a network -- typically, the internet. Users generally pay for their cloud data storage on a per-consumption, monthly rate. In this fast-moving world it become necessary to store data on the cloud storage. The biggest advantage of cloud storage is that we can store any type of data in digital form on the cloud. Another advantage of cloud storage is that we can access data from anywhere, anytime on any device. There are many cloud storage providers such as, Google Drive, Dropbox, OneDrive, iCloud, etc. They provide free service for limited storage but if you want to store beyond the limit, you have to pay. In this section, we will discuss what is cloud storage, uses of cloud storage, and its architecture in detail. References: 1. Discovering Computers 2016(First Edition) , Cengage Learning By Misty E. Vermaat; Susan L. Sebok; Steven M. Freund; Jennifer T. Campbell; Mark Frydenberg (Shelly Cashman Series) 2. Fundamentals of Computer( First Edition-2009) Publisher: McGraw Hill By Balaguruswamy 3. Computer Fundamentals(First Edition-2010) Publisher: Person By Anita Goel