Lesson-1-v.2.pdf

 Lesson 1, Basic Definitions, aside from the course description, aims to give a general overview of what a computer is and lay the foundation of the science of computing. The module contents examine the overall aspect of computing, its relationship to Information Communication Technology, comp...

 Lesson 1, Basic Definitions, aside from the course description, aims to give a general overview of what a computer is and lay the foundation of the science of computing. The module contents examine the overall aspect of computing, its relationship to Information Communication Technology, components, operating systems, and internal organization of the computer system, which include CPU elements, memory, internal storage, and input/output units. The module contains concepts of computer storage devices, its functionality, the CPU terminology, memory functionality, trend and concepts, monitor and their controllers, video graphic, driver software, et cetera. Basic knowledge of data representation, data communication, networking, operating systems, database systems, web server and its properties, internet communication, and security will also be acquired in this module. ICT has become a necessary and acknowledged piece of regular day to day existence for some individuals. ICT is expanding in significance in individuals' lives, and it is expected that this pattern will proceed, to the degree that ICT education will turn into a useful necessity for individuals' work, social, and individual lives.  In the previous decades, data and correspondence advancements have furnished society with a vast range of new correspondence abilities. For instance, individuals can impart progressively with others in various nations utilizing innovations, for example, texting, voice over IP (VoIP), and video-conferencing. Interpersonal interaction sites like Facebook permit clients from everywhere worldwide to stay in contact and convey consistently. Present day data and technology advances have made the world a "global village," in which individuals can speak with others worldwide as though they were living nearby. Hence, ICT is regularly concentrated with regards to how present day correspondence innovations influence society. ▪ ▪ ▪ ▪ ▪ ▪ ▪  Data as a general concept refers to the fact that some existing information or knowledge is represented or coded in some form suitable for better usage or processing. It is a series of observations, measurements, facts, and communication. Computer data are information that is stored or saved inside a computer or a computing device. There are multiple types of data. Some of the more common types of data include the following: Single character Boolean (true or false) Text (string) Number (integer or floating-point) Picture Sound Video  Data is raw, unorganized facts that need to be processed. Data can be something simple and seemingly random and useless until it is organized. Each student's test score is one piece of data. When data is processed, organized, structured, or presented in a given context to make it useful, it is called information. The word comes from a singular Latin word, datum, which originally meant "something given." Its first usage dates back to the 1600s. Over time "data" has become the plural of datum. "Information" is an older word that dates back to the 1300s and has Old French and Middle English origins. It has always referred to "the act of informing," usually regarding education, instruction, or other knowledge communication. Data and Information – Input, Storage (Volatile/Non Volatile), Process, Output  Information is something that can be measure quantitatively. In the computing world, information often means as computer data. The primary unit of computer information is a bit. One bit of data consists of two values: 1 and 0. All computer data or information are converted to 1’s and 0’s, which can be understood and the process by any computing devices. Information is also organized or classified data, which has some meaningful values for the receiver. Information is the processed data on which decisions and actions are based. For the decision to be meaningful, the processed data must qualify for the following characteristics: Timely − Information should be available when required. Accuracy − Information should be accurate. Completeness − Information should be complete.  ICT stands for "Information and Communication Technologies." It refers to technologies that provide access to information through telecommunications. It is similar to Information Technology (IT) but focuses primarily on communication technologies. ICT includes the Internet, wireless networks, cell phones, and other communication mediums. In the past few decades, information and communication technologies have provided society with a vast array of new communication capabilities. For example, people can communicate in real-time with others in different countries using technologies such as instant messaging, voice over Internet Protocol (VoIP), and video-conferencing. Social networking websites like Facebook allow users from all over the world to remain in contact and communicate regularly.  Modern information and communication technologies have created a "global village," in which people can communicate with others across the world as if they were living next door. For this reason, ICT is often studied in the context of how modern communication technologies affect society.  A computer is a machine or device that performs processes, calculations, and operations based on instructions provided by a software or hardware program. It can accept data (input), process it, and then produce outputs. Computers can also store data for later use in storage devices and retrieve them whenever it is necessary. Modern computers are electronic devices used for a variety of purposes ranging from browsing the web, writing documents, editing videos, creating applications, playing video games, etc. Basic Parts of Computer A PC is comprised of various parts. These parts cooperate to do specific tasks. These parts are called “devices,” and they are: 1.3.1 - The Input devices; 1.3.2 - The System Unit or Processing device; 1.3.3 - The Output devices; 1.3.4 - The Storage devices.  In a computer system, the input devices are hardware peripherals that are used for communication between humans and computers. Input devices send signal to the computer as input to command a computer machine what to do. Some of the popular input devices are: KEYBOARD The keyboard is one of the many ways to communicate with a computer. It looks like a typewriter, has many buttons and are called “keys”. You use the keyboard to type letters, numbers, and symbols to give instructions to the computer.  MOUSE The mouse is another important tool for communicating with computers. Commonly known as a pointing device, it lets you point to objects on the screen, click on them, and move them. The mouse allows you to control the movement of an on-screen pointer, and when you move the mouse, the cursor will also move. You can use the mouse to tell the computer what to do. MICROPHONE A microphone is a sound-detecting device that can be attached to a computer. It allows you to input sounds like speech and songs into the computer. You can record your voice with the help of a microphone.  WEB CAMERA A web camera is used to take live photos videos. You can save them in the computer. All cameras are made of semiconductor device called CCD, which means, Charged Coupled Device. It is the sensor that sense images and convert it to digital signals. JOYSTICK A joystick makes computer games a lot more fun. When it is moved, it passes information to the computer. Most joysticks are used in game applications and program simulation of animations.  SCANNER A Scanner scans and copies pictures and pages, and turns them into images that can be saved on a computer. It is often part of a printer and one of the features of it. Scanners are like Xerox machines that can directly duplicate text and images.  Things to explore… Do you wonder how those input devices operate? Could you try to open any input devices (e.g. mouse, keyboard, & joystick) and identify its internal electronics parts? Could you do a research work and document what sensors are used in the different input devices that humans used to communicate to a computer?  The System Unit or Processing device is the metal and plastic box that contains the main components of the computer, including the motherboard, memories, central processing unit (CPU), on/off button, and power supply. When you think, you use your brain. In the same manner; system unit has the CPU as the main brain of the processing device. It tells the other parts of the computer what to do. It is the controlling part of a computer that controls all the input and out peripheral devices. A system unit and its basic components. Figure courtesy of sites.google.com/ComputerSavvy.  An output device is a part of a complete computer hardware that receives data and signals from a system unit and then translates that data into another form. That form as output may also be data or signals like audio, video, character texts, or paper hard copy printed as document. The difference between an output device and an input device is that an input device sends data into the computer, whereas an output device receives data and signals from the system unit. Some examples are:  MONITOR The monitor works with a video card, located inside the computer case, to display images and text on the screen. Most monitors have control buttons that allow you to change your monitor's display settings, and some monitors also have built-in speakers. The monitor is like a window or a rectangular screen that are made of special semiconductors that light when a signal is triggered by the system unit. Inside the screen are texts and graphics that perform interaction between human and the computer. PRINTER A printer prints the results of your work from the computer screen on a sheet of paper. This is called a printout. It takes data from the system unit and output those data as printed document. Those printed documents are composed of texts and images.  SPEAKERS/HEADPHONES The speakers and headphones are the output devices that produce different types of sounds processed by the computer. Speakers are made of electrical components called transducers that convert electrical signal from the processing unit to audible signals. You can listen to songs or speeches stored in the computer with the help of speakers.  The storage devices that are used in computers are special devices made of special materials. Some are made of special mechanical devices that are coupled with magnetic materials. Many years ago, data was stored in papers and cardboards. Nowadays, most storage devices are made of special semiconductor materials using special and advanced physics technology. Both of the mechanical and semiconductor types of storage materials used these advanced technologies to store data and digital signals. Below are some of these storage devices.  HARD DISKS The hard disk is a part of a computer which is used for storing data. Storing data devices are called storage devices. These medium of storage are semi-magnetic disks that are called platter. They help in storing any work done on a computer permanently. Inside the system unit is a hard disk that is made up of one or more metallic disks. It stores a large amount of information. FLOPPY DISKS A floppy disk stores small amounts small amounts of information. It works when it is inserted into the floppy drive. The floppy drive is fixed in the system unit. It is also made of magnetic devices formed in a thin film type disk-shaped inside the disk cartridge. Currently, floppy disks are not used anymore because of its small storage capacity.  COMPACT DISKS A Compact Disk or CD stores many times more information than a floppy disk. It is made using glass and laser technology. Data are stored using sophisticated light technology and light beam aimed into the glass disk by mechanical precision achieving high data storage capacity. This compact disk works when it is inserted into the CD drive wherein a laser reader and sensor read the data impose from the compact disks. The CD drive is fixed in the CPU. Take note that compact disk is a light sensitive storage device and improper handling of it may result in the loss of data stored. USB FLASH DRIVE A USB Flash Drive (Universal Serial Bus) is a portable storage device, small and lightweight enough to be transported on a keychain or in a pocket. It is made of a special type of semiconductor device using advanced semiconductor doping technology. The average USB flash drive can hold about 2 billion characters. Flash drive is also called thumb drive.  RAM or RANDOM ACCESS MEMORY A RAM (Random Access Memory) is the internal, physical memory hardware device installed in the motherboard of the system unit. This storage device helps the central processing unit (CPU) in the execution of the operating system (OS), application programs and other data application. Like the flash drive, RAMs are made of special semiconductor materials that stores electrical signals as digital data. Random Access Memory is a volatile memory material meaning data will be lost if the system’s power is not present.  Below are most of the characteristics of a computer. It is an inanimate object. o It needs outside intervention for it to run. o It can only do things for which it is intended. It is electronic. o It is made up of electronic circuits. o It is powered by electricity. It is automatic. o It can set up its internal operations on its own. o The various functions are executed automatically by way of a stored computer program.  It can manipulate data. o Following specific rules, it can perform arithmetic functions such as addition, subtraction, multiplication, division, and other complex mathematical operations. It has a memory. o It can remember what it has done. o It can store instructions in its memory and follow these through unaided. o It can store a large amount of data in a compact and easily retrievable form. It has logic functions. o It can perform specific decision instructions automatically. o It can determine whether a specific statement is true or false.  CAPABILITIES 1. Speed. It operates at the speed of electronic flow, measured in billionth and trillionth of a second. 2. Repetitiveness. It can perform the specified tasks repeatedly. 3. Accuracy. When the machines are programmed correctly, and when input data is error-free, the accuracy of the output is relatively assured. 4. Decision-making capability/ logical operations. It can decide based on the data and commands that the users input. 5. Store and retrieve information. It can save and retrieve information for future use. 6. Ability to check itself. Computers can check their work. 7. Ability to communicate with other users or machines. It can share files and resources, among other computers.  There are three basic kinds of computers. These kinds are based on the hardware structure and the way physical quantities are represented in a computer. The following are the three types. Analog Digital Hybrid  An analog computer is a special type of computer, where to use data in continuous form, not discrete, and a changeable constant stream of data is known as “Analog Data.” Analog PCs can store simple information in steady physical amounts like electrical potential, liquid weight, or mechanical movement, lastly, it creates the outcome utilizing measures. Analog PCs are used in such zones, where to require information to be measure straightforwardly without changing into numbers. Simple PC utilizes the projects for converting complex equations into an analog circuit. Analog computers are the first computers being developed and provided the basis for the development of modern digital computers. Analog computers are widely used for specific specialized engineering and scientific applications, calculation and measurement of analog quantities. They are frequently used to control processes such as those found in an oil refinery where flow and temperature measurements are essential. They are used, for example, in the papermaking and chemical industry. Analog computers do not require any storage capability because they measure and compare quantities in a single operation. The output from an analog computer is generally in the form of readings on a series of the dial (Speedometer of a car) or a graph on a strip chart.  Hybrid Controller Simulation of a Spaceship Mass-Spring-Damper System Simulation of Car-Suspension System Vehicle Simulation Speedometer Telephone lines Frequency of Signal and Voltage Oscilloscope Television Analog Sound Processor Operational Amplifiers Mechanical Integrators Wheel balancing computer  A Slide Rule is the most straightforward type of analog computer, and this computer helps to produce an approximate result for simple mathematical operations. All users slide the hashed rod to line up along with several marking in the other rod, and it helps to read this equipment depending on the line up of different kinds of hash marks.  Differential Analysers were analog computers designed to solve for all differential equations. These computers had a large size for modern computers because today those computers fill space like a PC. In the image is an obsolete differential analyzer that was used in Calculus.  Castle Clock has a better representation of several uses to mechanical analog computers; Al-Jarazi developed the castle Clock Analog Computer. This computer was able to store different programming commands. Castle Clock computer’s height was 11 feet, and it takes a round of moon and sun. The computational part of this computer permitted users to set variable length of the day depends on the running season. In the picture above is a sample castle clock from Dinan, France.  Mechanical analog computers are designed along with different components such as gears and lever, which do not use electronic parts. It produces output while turning of gears, and it can perform multiplication and division operations. Examples are – Cosmic Engine, Pascaline, Stepped Reckoner etc.  Pneumatic analog computers use the compressed air in the form of a power source that is very simple and inherently analog, and these computers are mostly used in the military and non-residential building areas. Input signal lines were calculated by the use of controlled air supplied to the inside of the computer, and the desired output signal in the form of air pressure was achieved through configurations in the analog box. Most pneumatic analog computer principle today was integrated into many medical devices like the mechanical and digital ventilators that were used in almost all hospitals for helping patients with lung problems.  A hydraulic analog computer uses liquid, mostly oil, to perform mathematical calculations. The first analog computer was used to solve differential equations. It was invented by Mihalo Petrovic Alas (1892), a member of the Serbian Royal Academy of Sciences, and was a professor of Theoretical Mathematics and Physics at Belgrade. The MONIAC (based on Alas’ works), also known as the Phillips Hydraulic Computer and the Finance phalograph, was created in 1949 by the New Zealand economist Bill Phillips to model the national economic processes of the United Kingdom, while Phillips was a student at the London School of Economics. There are four types of computers with their classification, such as: 1.5.1 - By Size and Capacity 1.5.2 - By Operating System Capabilities 1.5.3 - Based on Number of Microprocessors 1.5.4 - Based on the Number of Users  Super Computer In the old days, large enterprises and organizations used the supercomputer because they required large-scale computing power. A supercomputer is architectural and operational depend on parallel and grid processing because, with the help of thousands of processors, all processes are executed simultaneously. Supercomputer mostly implemented in large scale scientific and engineering areas, because where required maintenance for a large amount of database. Some examples are: Titan Sequoia Functions are: K Computer Industrial function Mira Space exploration JUQUEEN Weather forecasting Super MUC Nuclear testing  Mainframe Computer Mainframe computer uses primary memory such as (RAM) and multiple processors. It serves as a central processing unit for all workstations and terminals points associated with it. A mainframe computer was designed to be used to process large amounts of data in pet bytes. It able controls thousands of users at one time. Mainframe ‘means a frame to hold multiple processors and main memory. Some examples are: Banking Government Education system Functions are: Government data processing Banking Insurance  Mini Computer The minicomputer is introduced in the mid-1960. This type of computer is a small size compared to a supercomputer and mainframe computer. In which had been used the different technologies such as transistors and core memory. “Digital Equipment Corporation” was made the first minicomputer with the US $161000. In this computer also, multiple persons can work at a time without waiting. Some examples of minicomputers are: Tablet PC Desktop minicomputer Functions are: Process monitoring Data acquisition Feedback Control work at a time without waiting.  Micro Computer The microcomputer is small in size. You can say it equivalent to personal computers. Microcomputers use different technologies like CPU (one single chip), Microprocessor, Input/output devices, and other storage parts. This is a multi-User computer that is a significant advantage. Some examples are: PDA PC Smartphone Notebooks Functions are: Application processing Education Amusement  Embedded Computer An embedded computer is a microcontroller technology-based system, and this has been designed for a specific task. An embedded computer does not need more power for massive computing. These computers can support some devices. Examples are: DVD Player/Recorder Medical Equipment Printer Fax Machines Washing Machine Industrial Equipment Home Automation  An operating system is the most critical software that runs on a computer. It manages the computer's memory and processes, as well as all of its software and hardware. It also allows you to communicate with the computer without knowing how to speak the computer's language. Without an operating system, a computer is useless. Your computer's operating system (OS) manages all of the software and hardware on the computer. Several different computer programs are running simultaneously, and they all need to access your computer's central processing unit (CPU), memory, and storage. The operating system coordinates all of this to make sure each program gets what it needs. Example of Operating Systems Operating systems usually come pre-loaded on any computer you buy. Most people use the operating system that comes with their computer, but it's possible to upgrade or even change operating systems. The most common operating systems for personal computers are Microsoft Windows, macOS, Unix, and Linux.  Modern operating systems use a graphical user interface, or GUI (pronounced gooey). A GUI lets you use your mouse to click icons, buttons, and menus, and everything is displayed on the screen using a combination of graphics and text. Microsoft Windows Microsoft created the Windows operating system in the mid-1980s. There have been many different versions of Windows, but the most recent ones are Windows 10 (released in 2015), Windows 8 (2012), Windows 7 (2009), and Windows Vista (2007). Windows comes pre-loaded on most new PCs, which helps to make it the most popular operating system in the world.  macOS macOS (previously called OS X) is a line of operating systems created by Apple. It comes preloaded on all Macintosh computers or Macs. Some of the specific versions include Mojave (released in 2018), High Sierra (2017), and Sierra (2016). According to StatCounter Global Stats, macOS users account for less than 10% of global operating systems—much lower than the percentage of Windows users (more than 80%). One reason for this is that Apple computers tend to be more expensive. However, many people do prefer the look and feel of macOS over Windows.  Linux Linux (pronounced LINN-UX) is a family of open-source operating systems, which means they can be modified and distributed by anyone around the world. Linux is different from proprietary software like Windows, which can only be modified by the company that owns it. The advantages of Linux are that it is free, and there are many different distributions—or versions—you can choose from. According to StatCounter Global Stats, Linux users account for less than 2% of global operating systems. However, most servers run Linux because it's relatively easy to customize. Linux has many distributions today, and some are Ubuntu, Fedora, Linux Mint, OpenSUSE, PCLinuxOS, Debian, Mandriva, Red Hat, Kali, Sabayon/Gentoo, etc. They have the entire common core Linux, but the difference is in their different capabilities and usage applications.  1. Sequential Computers: The sequential computing is traditional architecture. In this model, all instructions are performed one by one, so the speed of this computing is slow compare to parallel computing. 2. Parallel Computers: Parallel computing is an imaging type of model in which many processors or applications execute simultaneously. In parallel computing splits the overload work into more than one processor and computation simultaneously. Classification of Parallel Computing: Bit-level parallelism Instruction-level parallelism (ILP) Data Parallelism Task Parallelism  1. Single User In this model, only one user can perform a task at a time. 2. Multi-User In this model, only multiple users can perform tasks at a time. 3. Network Types In this model, which has unique functionality, the connection between computers and other terminals is connected with the local area network.  Information and communication technologies are becoming tangled with our everyday lives in the industry, the service sector, transport, logistics, health care, housing, education, and our leisure time, almost without discerning it. As human beings, we are always attached to a lot of essential things in our life. Jobs, education, retailing, and banking these are the compulsory things in our life. It was tough to get in touch with these before technology changed our life and made it easier for us.14a It has contributed a lot to exchange our experience from writing a letter which could take one month to arrive in the receiver, to writing an e-mail which can be received by the receiver in just one minute, from going to the shop to choose and buy things to select and buy using E- commerce and no one even needs to go to the shop to collect their goods. Sticking with the book for the whole day can be very amusing for the students. Thanks to IT, this introduced us to an innovative way of studying. Some of the topics are described in more detail below, which are changed because of IT. Some of the applications of ICT are:  Information and technology have helped a lot in the field of jobs. IT industry introduced some unique and rare jobs which weren't very popular even in late 1980. This field has appeared as a solution to increase the number of employments and reduce the number of unemployment in our society. The IT industry created a lot of job facilities for people who have skills in IT. It has created jobs like- Web developer, IT network administrator, computer game designer, IT technicians, etc. The IT industry also helped many people to become successful self-employer. For example-Steve Jobs, who was the founder of Apple Inc. along with Ronald Wayne. Bill Gates is the founder of “Microsoft.” Mark Zuckerberg, the founder of the famous social networking site, “Facebook.” This is also helpful because they have also employed people in their own company, which is also part of the IT industry. It has not only created jobs for many people, but it has also taken away many positions in society. For example- nowadays, people like to buy their products online, which has led to a reduction in floor jobs. For instance- Comet has gone into administration because it can’t cope with online competition from other online shopping like Amazon and eBay.  Education Technology helped us in our education as well. This has introduced the most comfortable way of learning and teaching for both students and teachers. It has also introduced us to know about modern discoveries and even historical things as well. We can use the internet everywhere in different books, and again we can watch videos on the internet to get more ideas about the topic that we want to research on. Nowadays, we use a projector in our school and other educational fields to discuss the work with the whole class.  Education We can also get ideas by reading blogs about different things and also discuss each other’s views about some topics that are related to education using blogs. We can again ask a question from our teacher using emails while we are at home, which could be very important, especially before the exam day and we can also research on the internet, and we don't have to look at the books and find the right page. This saves a lot of time for the students. We can also take help from our friends to learn in a collaborative environment. Although there are some advantages of using IT in our education, it also has some disadvantages as well. Nowadays, people rely on the Internet too much that they believe in everything that is written on the web page. It has also taken jobs from the library because most of the people rely on the internet library because they can buy their favorite books on the internet. So libraries are shutting down because people depend on the Internet library.  Money and Banking IT has also shown its valuable points on money and banking, which helped us a lot to buy necessary things using E-commerce, which includes online shopping, online selling, etc. It also helped a lot of companies to deal with other companies. We can use online money and banking service 24/7 hours a day. This means people can use this benefit whenever they want from any part of the world. We can also go to different countries and use our same banking account to make money or put money in our store. This is possible because of the WAN (Wide area Network.) We can also get a monthly statement using the internet, so we can compare our information every month and make our plan for the upcoming months. Money transfer for another country through banking will be a simple task. IT has also introduced us to an Eco-friendly world by using fewer papers for money and banking. All the information can be stored on our computer, and we don't have to worry about losing important documents.  Money and Banking We sometimes face significant problems using IT in Money and banking. Many people make malicious software that is used to hack other information on the computer. So when someone stores their bank information on their computer, those hackers steal their data and use it for their gain. Sometimes it can happen to any company, and as a result, they can lose all of their consumers' data. Phishing is another method used by those people to hack information using the internet. The company also needs to hire a lot of staff who have IT skills, which means a lot of resources need to be spent on staff and computers to store customers’ information.  Business Communication is an essential technique that is used to make a business very famous. In earlier days, people used to communicate differently. They had to go to everyone's house to promote their products, which could take a long time to promote their work. They sometimes used to take a long journey so that they can deal with someone, and they can expand their business. Since technology has arrived, people still using the technique, which is communication, but they have changed the method of promoting their products or dealing with someone who is far from one another. Instead of going to everyone's house separately, people are making an advertisement, which not involves one area or a country but the whole world and we can also use IT to communicate someone who too far from each other. We can use the e-mailing method to learn more about our customers. They can again frequently ask us some questions related to our business.  Business But sometimes we can't rely heavily on writing e-mails because we can't sometimes share what we are feeling or what we are want to ask. So it becomes very compulsory for us to have face to face communication with them. This is when we exploit IT in our life. Video conferencing assembled us via the internet. We can use this technique to communicate with someone face to face, and we can use this benefit for meeting or if we are trying to work together with other companies which can be situated in other countries. Information Technology also has some adverse effects on Business. We rely too much on technology, and so we always put whatever we do on our computers. So it increases the cost of a company as the company needs to use LAN and WAN to expand its businesses. Our servers can also crash or get damaged, and it can cost millions of pounds for the company to repair. The chance of losing the whole companies files are random as well. It can sometimes make it easier for hackers to break the firewall of the company and use it for their purposes. So the company needs an extra employer, which is a network administrator who deals with these things and therefore, the company has to pay him as well.  Health When we get sick, we don't want to go to many places other than home. But from home going for a consultation to a doctor, we need to move physically. Taking an appointment, talking to the receptionist, describing the problem we have, and then waiting for it increases our illness. This is when IT comes to helping us. Nowadays, we don't need to go to the doctor's and describe our problems; we can use the Internet to contact our doctor. We can use also use IT to do face to face communication with our doctor even though we are at home. We can again frequently ask a question to our doctors, and they can also answer us using E-mails.  Health Making an appointment is not necessary to contact our doctors, and we can get our prescriptions at whatever point we need. We can likewise utilize this office to find out about our ailment and how to fix ourselves. We can look on the web to explore about the illness and the medication we need to use to show signs of improvement. It can benefit students who are studying to become doctors and who like to know more about different kinds of medicines. IT provides us with a lot of advantages. But it also has some disadvantages. If someone uses a computer for a long time, then they can get a headache, it can also cause neck pain, can make them nothing apart from sitting in front of the computer. Some teenagers also put too much time on their games instead of studying or taking part in different physical activities. Some people even get stretch if they get bullied on the internet, which may stop them from going outside, and they sometimes feel scared to talk to anybody.  Crime and Policing IT has introduced a lot of things that prevent people from committing a crime. CCTV camera, GPRS system, using a database for finding criminals' information is not an ordinary thing, which is not impossible without the blessing of IT. In ordinary days police use GPRS to track someone's car, mobile phone if it has been stolen. Authority uses a CCTV camera to detect criminals' faces. A fingerprint is another particular method with which the police can identify the thieves. This is making our lives safer and very easy in many ways. For example- big supermarkets like ASDA or Tesco don't need to think about too much if someone tries to still their products, because some products have got chips which can be detected if that product isn't swiped over the bar code reader. They can also use CCTV cameras to help them protecting their products.  Crime and Policing The main disadvantage created by the technology system is that anyone who knows how to make a program, they can hack others device using viruses, Phishing, and also Malicious software. They can be very threatening because they can take your information, which can be very confidential for you. I.e., Your bank card. Sometimes people also delete other files to annoy people, which can lead someone to lose their essential work as well.  Retailing IT has impacted on Retailing, and we are immensely enjoying the benefit of using IT on Retailing. We are using IT on Retailing, which helps us to buy anything 24/7 every day. We can use this facility to choose whatever we want at any time we want. We can select a range of items on the internet, and we don't even have to go to a place to choose whatever we want. We can also reserve the items on the internet. We can pay for the items on the internet with a safe internet payment option, which is PayPal. We can also choose products from different countries on the internet and buy them using the advantage of IT. IT also helped companies to make more money and spend less on their business. The company does not need to hire more staff for the company.  Retailing Although it has some advantages in retailing, there is some disadvantage as well. It can sometimes become very discouraging for small shops as they can't compete with big supermarkets like Tesco, which has both online shopping and average shopping facility for the consumers. So they have to close their shops. Sometimes the customers can't get their necessary staff when they needed because of the late delivery.