Chapter 5 Theory.pdf

END-USER COMPUTING STUDENT MANUAL CHAPTER 5: THEORY COMPILED BY: DR R BRINK COPYRIGHT RESERVED ©ACADEMIC DEVELOPMENT CENTRE – 2017 Learner Material ©Academic Development Centre...

END-USER COMPUTING STUDENT MANUAL CHAPTER 5: THEORY COMPILED BY: DR R BRINK COPYRIGHT RESERVED ©ACADEMIC DEVELOPMENT CENTRE – 2017 Learner Material ©Academic Development Centre TABLE OF CONTENTS CHAPTER 5. THEORY.......................................................................................................... 1 UNIT 1. INTRODUCTION TO COMPUTERS............................................................ 3 INTRODUCTION.............................................................................................................. 3 OUTCOMES...................................................................................................................... 3 ASSESSMENT CRITERIA............................................................................................... 3 1.1 What is a Computer?........................................................................................ 3 1.2 Software and Hardware.................................................................................... 4 1.2.1 Software........................................................................................................... 4 1.2.2 Hardware.......................................................................................................... 5 1.3 Computer Users and Professionals................................................................... 5 1.4 Types of Computers......................................................................................... 6 1.4.1 Super Computers.............................................................................................. 6 1.4.2 Mainframe Computers..................................................................................... 6 1.4.3 Midrange Computers........................................................................................ 7 1.4.4 Embedded Computers...................................................................................... 7 1.4.5 Cloud Computing............................................................................................. 7 1.4.6 Mobile Devices................................................................................................ 8 1.4.7 Personal Computers......................................................................................... 8 1.5 Computer Networks and the Internet............................................................... 8 1.6 E-Mail............................................................................................................ 10 1.7 How Computers Impact Society.................................................................... 10 1.7.1 Benefits and Challenges of Computers and the Internet................................ 11 1.7.2 Environmental Concerns................................................................................ 12 UNIT 2. HARDWARE................................................................................................. 13 INTRODUCTION............................................................................................................ 13 OUTCOMES.................................................................................................................... 13 ASSESSMENT CRITERIA............................................................................................. 13 2.1 Digital Data Representation........................................................................... 13 2.2 Measurements of Memory and Hard Drive................................................... 14 2.3 Inside the System Unit................................................................................... 14 2.3.1 The Motherboard............................................................................................ 15 2.3.2 The Power Supply.......................................................................................... 15 2.3.3 Central Processing Unit (CPU)...................................................................... 15 2.3.4 The Hard Drive.............................................................................................. 16 2.3.5 Random Access Memory (RAM).................................................................. 17 2.3.6 The Bus.......................................................................................................... 17 2.4 Storage............................................................................................................ 18 2.4.1 Primary Storage.............................................................................................. 18 2.4.2 Secondary Storage.......................................................................................... 18 2.4.3 Hard Drives.................................................................................................... 18 2.4.4 External Hard Drives...................................................................................... 19 2.4.5 Solid State Hard Drives.................................................................................. 19 2.4.6 Hybrid Hard Drives (Solid-State Hybrid Drives).......................................... 19 2.4.7 Encrypted Hard Drive.................................................................................... 19 2.4.8 Flash Memory Storage Systems..................................................................... 20 2.4.9 Network and Cloud Storage Systems............................................................. 20 End-User Computing (Extended) – Theory Page ii University of Johannesburg Learner Material ©Academic Development Centre 2.4.10 Smart Cards.................................................................................................... 21 2.5 Input Devices................................................................................................. 21 2.5.1 Keyboard........................................................................................................ 21 2.5.2 Pointing Devices............................................................................................ 21 2.5.3 Touch Devices................................................................................................ 21 2.5.4 Stylus.............................................................................................................. 22 2.5.5 Scanner........................................................................................................... 22 2.5.6 Barcode Reader.............................................................................................. 22 2.5.7 Radio-Frequency Identification (RFID)......................................................... 22 2.5.8 Biometric Readers.......................................................................................... 23 2.6 Output Devices............................................................................................... 23 2.6.1 Monitor........................................................................................................... 23 2.6.2 Printer............................................................................................................. 23 UNIT 3. COMPUTER SOFTWARE........................................................................... 25 INTRODUCTION............................................................................................................ 25 OUTCOMES.................................................................................................................... 25 ASSESSMENT CRITERIA............................................................................................. 25 3.1 Functions of an Operating System................................................................. 25 3.2 Differences between Operating Systems....................................................... 26 3.3 Types of Operating Systems.......................................................................... 26 3.4 Application Software..................................................................................... 27 3.5 Desktop vs Mobile Software.......................................................................... 27 3.6 Application Software for Businesses............................................................. 27 UNIT 4. COMPUTER NETWORKS........................................................................... 28 INTRODUCTION............................................................................................................ 28 OUTCOMES.................................................................................................................... 28 ASSESSMENT CRITERIA............................................................................................. 28 4.1 Business Use of Computer Networks............................................................ 28 4.2 Personal Use of Computer Networks............................................................. 29 4.3 Network Characteristics................................................................................. 29 4.4 Wired vs Wireless Network........................................................................... 29 4.5 Network Topologies....................................................................................... 29 4.6 Network Architecture..................................................................................... 30 4.7 Network Sizes and Coverage Areas............................................................... 31 4.8 Data Transmission.......................................................................................... 32 4.9 Wired and Wireless Networking.................................................................... 34 4.10 Communications Protocols and Networking Standards................................. 35 4.11 Networking Hardware.................................................................................... 37 UNIT 5. THE INTERNET........................................................................................... 40 INTRODUCTION............................................................................................................ 40 OUTCOMES.................................................................................................................... 40 ASSESSMENT CRITERIA............................................................................................. 40 5.1 Evolution of the Internet................................................................................ 40 5.2 Connecting to the Internet.............................................................................. 41 5.3 Selecting the Type of Device......................................................................... 41 5.4 Choosing a Type of Internet Connection....................................................... 42 5.5 Selecting an Internet Service Provider (ISP)................................................. 42 5.6 Set up your Computer to Use the Internet...................................................... 42 5.7 Searching the Internet for Information........................................................... 43 End-User Computing (Extended) – Theory Page iii University of Johannesburg Learner Material ©Academic Development Centre 5.8 Common Internet Communication Methods and Activities.......................... 43 UNIT 6. SECURITY AND PRIVACY........................................................................ 44 INTRODUCTION............................................................................................................ 44 OUTCOMES.................................................................................................................... 44 ASSESSMENT CRITERIA............................................................................................. 44 6.1 Internet Security Concerns............................................................................. 44 6.2 Network Security........................................................................................... 45 6.3 Identify and Protect Against Unauthorised Access and Use.......................... 46 6.4 Identify and Protect Against Computer Sabotage.......................................... 46 6.5 Identify and Protect Against Online Theft, Online Fraud and Other Dot Cons......................................................................................................................... 46 6.6 Describe and Protect Against Cyberstalking and Other Personal Safety Concerns....................................................................................................................... 47 6.7 Access Personal Computer Security and Identify Precautions...................... 47 6.8 Identify Privacy Concerns.............................................................................. 48 6.9 Discuss Current Security and Privacy Legislation......................................... 48 REFERENCE LIST.......................................................................................................... 49 End-User Computing (Extended) – Theory Page iv University of Johannesburg Learner Material ©Academic Development Centre CHAPTER 5. THEORY INTRODUCTION TO THEORY In this chapter you will learn what a computer is and what it consists of. You will understand what all the components of a computer are, as well as computer hardware, software and computer networks. You will also become familiar with the internet, and with security and privacy. OUTCOMES At the end of this chapter you will be able to:  Understand a computer and all its components.  Understand computer hardware.  Understand computer software.  Understand computer networks.  Understand the internet.  Understand internet security and privacy. End-User Computing (Extended) – Theory Page 1 University of Johannesburg Learner Material ©Academic Development Centre ASSESSMENT CRITERIA UNIT OUTCOMES ASSESSMENT CRITERIA After completing this unit you will be You will be deemed to be competent if you can: able to: UO1 Understand a computer and its AC1 Explain what computers do. components AC2 Identify the different types of computers. AC3 Describe computer networks and the internet. AC4 Distinguish between hardware and software. AC5 Distinguish between the different types of computers. AC6 Understand the impact that computers have on society. UO2 Describe computer hardware AC7 Understand how data is presented to a computer. AC8 Identify the parts inside the system unit. AC9 Explain how the CPU works. AC10 Describe the different types of storage systems. AC11 Identify and describe common input devices. AC12 Identify and describe common output devices. U03 Discuss computer software AC13 Explain system software and operating systems. AC14 Identify operating systems for personal computers. AC15 Identify operating systems for mobile devices and larger computers. AC16 Describe common types of application software. AC17 Describe application software used for businesses. U04 Discuss computer networks AC18 Explain what networks are. AC19 Identify network characteristics. AC20 Understand how data is transmitted over a network. AC21 Describe common types of networking media. AC22 Identify protocols and networking standards. AC23 Describe networking hardware. U05 Describe the internet AC24 Explain how the internet evolved. AC25 Set up your computer to use the internet. AC26 Understand how to search the internet for information. U06 Discuss internet security and privacy AC27 Explain network and internet security concerns. AC28 Identify and protect against unauthorised access and use. AC29 Identify and protect against computer sabotage. AC30 Identify and protect against online theft, online fraud, and other dot cons. AC31 Describe and protect against cyberstalking and other personal safety concerns. AC32 Assess personal computer security and identify precautions. AC33 Identify privacy concerns. AC34 Discuss current security and privacy legislation. End-User Computing (Extended) – Theory Page 2 University of Johannesburg Learner Material ©Academic Development Centre UNIT 1. INTRODUCTION TO COMPUTERS INTRODUCTION We are living in a technological age and whatever we do involves technology, therefore it is important to understand what a computer is and what it can do for you. This unit will lay the foundation for your EUC/Computer module. At the end of this unit, you will be able to explain what computers do. You will also be able to distinguish between the different components of a computer. OUTCOMES At the end of the unit you will be able to:  Understand a computer and its components. ASSESSMENT CRITERIA You will be deemed to be competent if you can:  Explain what computers do.  Identify the different types of computers.  Describe computer networks and the internet.  Distinguish between hardware and software.  Distinguish between the different types of computers.  Understand the impact that computers have on society 1.1 What is a Computer? A computer is a machine that allows the end-user to work on different programmes to perform useful tasks. The end-user will give a set of instructions to the computer in the proper order, and the computer will then provide a proper response to the end-user. A computer can perform both simple and complex operations. In this technological age, computers also perform communication functions, namely, sending and retrieving data via the internet. The user can also retrieve information through shared databases and exchanging e-mail messages. A computer is an electronic device that can perform four general operations namely, (i) expect data from an input device, (ii) perform operations on the data, (iii) present the results of the data, and (iv) store the data, as shown below. End-User Computing (Extended) – Theory Page 3 University of Johannesburg Learner Material ©Academic Development Centre Input Processing Output Storage User types in the Computer adds 2 and Computer displays the Computer saves the input data numbers 2 and 5 5 results. for future use. Image from Pinard, Romer and Morley From the information shown in the diagram above, it is important to understand the difference between data and information. Data is raw material that is captured by the user. For example, if the user types the following formula in a Microsoft Excel worksheet =2+5, the computer will add these two numbers together during the processing phase and then display the result as 7. In other words, the data is =2+5. Once it is processed into a meaningful form, i.e. 7, it becomes the information. It is important to understand that any facts or set of facts that you enter into a computer can become information. For example, if you type the name JOHN in Microsoft Word, the computer will process each character of the name JOHN before it is shown on your screen as the meaningful form, i.e. JOHN. This example will be clearer to you after the explanation of digital data representation in unit 2. 1.2 Software and Hardware Image from Google Images 1.2.1 Software Software refers to the programmes and data that are invisible and run inside the computer. Software can only be seen on the screen. It is bought from computer shops in boxes. There is usually a CD inside the box that you use to load the software onto your computer. You can also purchase software online and download it directly from the internet, for example, Windows, Image from Google Images Microsoft Office, games and maths programmes. End-User Computing (Extended) – Theory Page 4 University of Johannesburg Learner Material ©Academic Development Centre 1.2.2 Hardware Hardware refers to the physical parts of a computer. There can be internal and external hardware. External hardware refers to anything outside a computer. The external hardware of a computer is made up of any components connected to the computer, for example, the keyboard, mouse, system unit (computer case), monitor, microphones, speakers, printer and external hard drives. Image from Google Images Internal hardware refers to the internal components that are installed within the system unit (computer case), for example, the motherboard, central processing unit, RAM, hard drive, CD Rom and power supply. Image from Google Images 1.3 Computer Users and Professionals A computer user is a person who uses the computer; they are often called end-users. The users are people who use the computer to perform tasks and to obtain information. The user doesn’t need technical expertise to understand the computer fully. Computer professionals, on the other hand, are programmers who write the programmes for computers so that the users can use the programmes. Examples of computer professionals are system analysts, computer operations personnel, security specialists and developers. End-User Computing (Extended) – Theory Page 5 University of Johannesburg Learner Material ©Academic Development Centre 1.4 Types of Computers In the technological age that we live in, computers are found in every facet of life. In this unit the following types of computers will be discussed: super, mainframe, midrange, embedded, cloud, mobile devices and personal computers. 1.4.1 Super Computers Super computers are the most powerful and expensive type of computer on the market. They are high performance computers with a fast processing speed. A super computer has various applications, such as the performance of complex scientific calculations, modelling simulations and rendering large numbers of 3D graphics. Image from Google Images 1.4.2 Mainframe Computers A mainframe computer can support the processing requirements of hundreds and thousands of smaller PCs that are connected to it. It is used in large organisations that need to manage a large amount of centralised data. If you enter the workforce one day and you work for a bank, university or government, the computer that you will be working on will be linked to a mainframe. Image from Google Images End-User Computing (Extended) – Theory Page 6 University of Johannesburg Learner Material ©Academic Development Centre 1.4.3 Midrange Computers Midrange computers are also called minicomputers. A midrange computer is a small and inexpensive computer that performs the same tasks as a mainframe computer but is less powerful than a mainframe. A midrange computer can support a computer network which enables the users to share files and other resources. This computer is not designed for a single user but is used for a specific purpose by individual departments in a large organisation. For example, the production department will use a mini computer to monitor the production process. Image from Google Images 1.4.4 Embedded Computers An embedded computer is a single chip that can perform all the specific functions of a normal computer. It can be part of a large system but it relies on its own processor. Examples of embedded computers are: iPhone watches, cameras, cell phones, GPS, dishwashers, DVD players, TVs, coffee makers and automotive systems. Images from Google Images 1.4.5 Cloud Computing Cloud computing refers to an online option of storing and accessing your data and programmes over the internet. Instead of using a hard drive or a flash drive, you store and share your documents in the cloud. This is also a safe way of backing up your documents. These documents are available anywhere and anytime. Even if you don’t have your own computer with you, you can still access your documents. Examples of cloud computing include iCloud, Google Drive and Dropbox. Image from Google Images End-User Computing (Extended) – Theory Page 7 University of Johannesburg Learner Material ©Academic Development Centre 1.4.6 Mobile Devices A mobile device is also referred to as a handheld computer with built-in computing and internet capabilities. This device is designed to be portable and it can often fit in your hand. Examples of mobile devices are e-readers, smartphones and tablets. Image from Google Images 1.4.7 Personal Computers A personal computer is a small computer designed for a single user. It is designed to fit on a desk and is also referred to as a desktop computer. Image from Google Images 1.5 Computer Networks and the Internet A network is a collection of computers and other devices that are connected to one another to share hardware, software and data, as well as to communicate electronically. This means that you can share your data and communicate electronically with students in another country through the networks and the internet. Image from Google Images The internet is a global network that consists of millions of computers connected to each other using a telephone line, a modem and Wifi It is the largest and most well-known computer network in the world. The internet can be accessed with the smallest home computer or the largest server. These computers use the internet to share information, conduct video conferencing and to do online transactions. People invite other people to connect to their website by designing a website and hosting it at an Internet Service Provider (ISP). These websites receive an address which everyone on the internet can connect to using an internet browser such as Internet Explorer. End-User Computing (Extended) – Theory Page 8 University of Johannesburg Learner Material ©Academic Development Centre A website address usually looks something like www.uj.ac.za or www.google.com. The www in the website address stands for World Wide Web, which is a collection of web pages available through the internet. In the two examples of a website address given above, the first website address will take you to the web page of the University of Johannesburg (UJ), where you can find UJ documents that are located on the web server (see Examples 1 and 2). Example 1 Image from the University of Johannesburg website Example 2 Close Tab Open New Tab Toolbar Address Bar Shows the URL of the current web page Print screen from Google End-User Computing (Extended) – Theory Page 9 University of Johannesburg Learner Material ©Academic Development Centre 1.6 E-Mail E-mail stands for electronic mail. By using an e-mail package called Outlook and the internet, a person in South Africa can write a message to someone in the USA. Once connected to the internet, Outlook Express can be opened and a letter can be sent to anyone in the world who has an e-mail address. An e-mail address will look something like [email protected] or [email protected]. The three basic elements of an e-mail are as follows: Who are you sending the e-mail to? Type the e-mail address here, for example [email protected] Type the subject of the e-mail here, for example: Budget 2018 Message area This is where you type the message to the person. Signature In this line you provide additional information about the sender. Print screen from University of Johannesburg Outlook 1.7 How Computers Impact Society Today we find computers and the internet everywhere in society. Just imagine your life without a cell phone, a computer and the internet. What is the internet? It is a network of interconnected objects that are connected to a network of interconnected computers. Some examples are wearables such as the smart watch, smart appliances. These smart devices can be used in health care, education and agriculture. Images from Google Images End-User Computing (Extended) – Theory Page 10 University of Johannesburg Learner Material ©Academic Development Centre 1.7.1 Benefits and Challenges of Computers and the Internet Benefits Challenges  Ease/enhancement of communication  Security issues  Data/better and faster information  Privacy  Tracking  Legal and liability issues  Saves money  Compatibility  Store healthcare patient data  Complexity  Fewer human errors  Fewer employment prospects  Wearable technology  Technologically dependent life  Improved education  Standards  Personal safety monitoring  Costly Computers and the internet are here to stay. As with everything in life, we need to find a balance and not let them take control of our lives. We humans must remain in control. If you are not in control of technology, it can cause health problems. Physical health matters related to computers that have received the most attention recently are as follows:  Eyestrain and headaches  Back and neck pain  Effects of electromagnetic fields  Repetitive strain injury Computer technology improves productivity, but it can also be counterproductive and cause some irritants such as:  Noise  Stress from excessive monitoring Let’s look at the ergonomics of your working environment if you are working on a computer. Ergonomics is defined as the study of human factors related to computers. As computer use has increased, so has the interest in ergonomics. People are devising ways in which computers can be redesigned and used to increase productivity and avoid health risks. End-User Computing (Extended) – Theory Page 11 University of Johannesburg Learner Material ©Academic Development Centre Image from Google Images 1.7.2 Environmental Concerns Green computing is the term used when we reduce the use of hazardous materials, maximise energy use during the products’ life time and promote recyclability. This means that, as users, we will use our computers and the resources used in their manufacture in an environmentally friendly manner. How can we practise green computing? Images from Google Images  Develop a sustainable green computing plan  Recycle  Make environmentally sound purchases and decisions  Reduce paper consumption  Conserve energy End-User Computing (Extended) – Theory Page 12 University of Johannesburg Learner Material ©Academic Development Centre UNIT 2. HARDWARE INTRODUCTION Hardware refers to the physical parts of a computer. There can be internal and external hardware. This unit will focus on external hardware, which refers to anything outside of the computer, in other words, any components connected to the computer. OUTCOMES At the end of this unit you will be able to:  Describe computer hardware. ASSESSMENT CRITERIA You will be deemed to be competent if you can:  Understand how data is represented to a computer.  Identify the parts inside the system unit.  Explain how the CPU works.  Describe the different types of storage systems.  Identify and describe common input devices.  Identify and describe common output devices. (Source: Pinard, Romer and Morley) 2.1 Digital Data Representation Digital data representation is a very complex and confusing concept. Data is represented in 0s and 1s. Computers are digital and can only understand these two states. When you type your name in a document, millions of 1s and 0s are processed and sent through the motherboard to your central processing unit (CPU) and then to the software programme. For example, if your name is JOHN, in MSWord the CPU will process the 1s and 0s and send it to the software; then the name JOHN will be displayed on the screen. J = 1010001001 O = 1000010111 H = 1011110110 N = 1111000001 Thus all data consist of 1s and 0s and are processed by the CPU. End-User Computing (Extended) – Theory Page 13 University of Johannesburg Learner Material ©Academic Development Centre 2.2 Measurements of Memory and Hard Drive Prefixes are combined with the term byte to describe data that is larger than a byte. For example: Name Description The basic unit of information in a binary numbering system, for Bit example the 0 in J represents a bit. Byte One character, for example, the J of John 1 kilobyte (KB) Metric for 1,024 bytes, but is usually thought of as 1,000 bytes 1 megabyte(MB) Metric for 1 million bytes 1 gigabyte (GB) Metric for 1 billion bytes 1 terabyte (TB) Metric for 1 trillion bytes 1 petabyte (PB) Metric for 1,000 terabytes 1 exabyte (EB) Metric for 1,000 petabytes 1 zettabyte (ZB) Metric for 1,000 exabytes 1 yottabyte (YB) Metric for 1,000 zettabytes (Source: Pinard, Romer and Morley) 2.3 Inside the System Unit System unit components include the CPU, motherboard, RAM, hard drive, processor, memory module, cards, ports and connectors, as illustrated in the picture below. As mentioned in Unit 1, there can be internal and external hardware. In this section we will cover the internal hardware that is found within the system unit. The system unit is the main case of a computer and houses the processing hardware as well as other hardware components, namely, the hard drive, power supply and cooling fan. Image from Google Images This internal hardware will be discussed in the following section. End-User Computing (Extended) – Theory Page 14 University of Johannesburg Learner Material ©Academic Development Centre 2.3.1 The Motherboard The motherboard is like the internal chest area and arteries (veins) of the body. All the circuits inside the board transport the data like the arteries transport blood to the lungs and other body parts. Images from Google Images The motherboard, which is also referred to as the main board, is basically a large circuit board. In addition to housing the CPU, RAM and processor chips, the motherboard also has expansion slots for expansion cards such as screen cards, sound cards and video cards. All the computer devices must be connected to the motherboard through different ports that link them to the motherboard. 2.3.2 The Power Supply The power supply provides energy to the computer in the same way that a human heart draws blood from the lungs and pumps it to the rest of the body so that it can function. If there is no power supply to the computer, the computer will not function. The power supply also connects to the motherboard so that it can deliver electricity to the computer. The power supply of a computer draws alternating current from the wall socket, converts it into direct current and then delivers it to the rest of your computer. Images from Google Images 2.3.3 Central Processing Unit (CPU) The brain is the central organ of the nervous system of a human being. The central processing unit (CPU) inside the box is similar to the human brain - without it, the machine cannot End-User Computing (Extended) – Theory Page 15 University of Johannesburg Learner Material ©Academic Development Centre function. Both the brain and the CPU control the activities of the body and of the computer by processing, integrating and co-ordinating the information that they receive. Images from Google Images This CPU is found on the motherboard inside the computer and it determines the speed of your computer. The faster the CPU, the faster the computer. The speed of the CPU is measured in megahertz (MHz). It consists of two main components, the control unit (CU) and the arithmetic logical unit (ALU). The CU fetches the instructions from the main memory and then executes the instructions. The ALU carries out all the arithmetic and logical operations of the data. The data that is entered into your computer through your input device is processed into information in your CPU. The processing part of the CPU can be compared to the thoughts of a human being which you cannot see or hear. Everything happens inside. Images from Google Images 2.3.4 The Hard Drive The hard drive is like the hippocampus area of the brain which is essential for memory function, particularly the transfer of information from short-term memory to long-term memory. Long- term memory is everything that you will never forget. The same thing applies to the hard drive - all the information on it is permanent. Images from Google Images End-User Computing (Extended) – Theory Page 16 University of Johannesburg Learner Material ©Academic Development Centre 2.3.5 Random Access Memory (RAM) The random access memory (RAM) is like the front part of the brain that stores information temporarily. The name random access memory is derived from the fact that data can be stored and retrieved randomly. The main function of RAM is to temporarily hold instructions and data needed by the CPU. If a power failure should occur, all data and instructions in the RAM will be lost forever because RAM cannot store information permanently, in the same way as you forget someone’s name a day or two after you have been introduced to them. Images from Google Images 2.3.6 The Bus The muscles of the body allow human body to move. They are the only tissue in the human body that has the ability to contract other parts of the body and force them to move. The muscles are similar to the bus. The bus is an electronic pathway that allows movement of data before it is saved on your storage devices. It is made up of multiple lines, which may be wires or conductors on a printer board. A system bus connects the CPU with the motherboard and other system components. Images from Google Images End-User Computing (Extended) – Theory Page 17 University of Johannesburg Learner Material ©Academic Development Centre 2.4 Storage All the data used in a computer needs to be stored and saved for future use. It is important to understand that two main types of storage are used, namely primary and secondary storage. 2.4.1 Primary Storage When you create a document in Microsoft Word, both the programme - Microsoft Word - and your documents are only temporarily stored in RAM. This refers to primary storage. RAM holds instructions and data for immediate access and use by the CPU. RAM is volatile, which means that data and instructions are lost when the computer is turned off. 2.4.2 Secondary Storage Secondary storage devices are also known as auxiliary storage and they are non-volatile, meaning that saved data and instructions remain intact when the computer is turned off. Secondary storage devices are designed to retain data and programmes permanently. There are many secondary storage devices. These are discussed below: 2.4.3 Hard Drives A hard drive is usually the largest data storage device inside the computer. All programmes and data the computer needs to operate are stored on this drive. Hard drives can store large amounts of information. A hard drive is non-volatile, and stores and retrieves data permanently. A hard drive that is permanently sealed inside the hard drive case, along with read/write heads, is called a magnetic hard drive. The magnetic hard drive’s read/write heads never touch the surface of the hard disks, even during reading and writing to the hard disk. The hard disk is organised into tracks, sectors, clusters and cylinders. Image from Google Images A track looks like the rings of an old tree. They are called concentric rings, as shown in the picture above. Each of these tracks on the hard disk is divided into sectors. A sector looks like a piece of a pie. A sector can hold 512 bytes of data. A cluster, or file allocation unit of the hard drive, is the smallest managed section that holds a file on the hard drive. Lastly, a cylinder is a set of all tracks of equal diameter in the hard disk drive. End-User Computing (Extended) – Theory Page 18 University of Johannesburg Learner Material ©Academic Development Centre 2.4.4 External Hard Drives An external hard drive is a portable storage device that can be attached to your computer either through a USB connection or wirelessly. External hard drives typically have high storage capacity and are sometimes used for backup purposes. Image from Google Images 2.4.5 Solid State Hard Drives Hard drive disks are available in various formats and standards such as hard disk drives, with one or more rotating disc storing data magnetic principles. Solid-state drives have no moving parts; they function on memory similar to flash memories, also referred to as USB flash drives. Solid-state drives are found in more expensive computers because of the cost of solid-state drives. 2.4.6 Hybrid Hard Drives (Solid-State Hybrid Drives) Hybrid hard drive disks consist of various formats of HDD and connectors. These combinations of various HDD utilising solid state HDD and the traditional SATA HDD enhance the performance of hardware on a computer. The solid state HDD are quick to respond and not movable, whereas the traditional SATA-type HDD have to start up and take time to become operational. The principle is to use the solid HDD to run the OS and to enhance the speed of the computer. Thereafter, the traditional cheaper HDD is used to store large files that are not used regularly. The hard drive disks are less expensive and combine small solid state hard drives for frequent use and hard drive disks for basic storage. 2.4.7 Encrypted Hard Drive A hard drive disk can be encrypted using various encryption techniques software. The process of encryption converts data into an unreadable code that protects data from being viewed. The encryption can be done by encrypting files, the volume or the full hard drive disk. Encryption is designed to encode data in such a way that the data is not visible to unwanted views by unauthorised individuals. Software and hardware encryption techniques are available to protect data from unauthorised access. End-User Computing (Extended) – Theory Page 19 University of Johannesburg Learner Material ©Academic Development Centre 2.4.8 Flash Memory Storage Systems Flash memory storage systems, such as the traditional thumb drive or flash drive, are small storage devices that are available in many forms and storage capacities. This storage system is portable and is used daily to store and transfer data files. The storage medium uses the same working principles as the solid state drive, and stores data until it is overwritten. The data can only be overwritten a specific number of times, after which the device will become non- functional. The data is continually overwritten when new files are backed-up to this storage device. Flash memory devices, or variants thereof, can be found in many data storage devices such as smart phones, digital cameras, video games, memory cards and flash memory storage modules called thumb drives. 2.4.9 Network and Cloud Storage Systems Network attached storage (NAS) is a dedicated storage server with its own IP address which can be connected to via the internet or VPN depending on system setup. These storage servers are usually shared by small companies via a computer network. The IP address is crucial to locate and connect to the server via the internet or communication network. Image from Google Images Various types of NAS focus on storage of data, sharing and the back-up of data, hosting email and databases, as well as integrating social media platform accounts. Cloud storage servers don’t have the functionality and diversity of network attached storage servers, which are hosted by business with specific clients’ needs in mind. The specific position of cloud servers or area of storage is non-specific, and data can be moved to storage servers more effectively, and protected using encryption and block duplication. Geographically, cloud servers can be located anywhere in the world. Network attached storage servers are not complicated to set up, using multiple operating systems such as Windows, at low cost. Cloud storage is free for the first volume of data; thereafter the cost increases. In the short-term, network attached storage will be more expensive, however, cloud storage incurs monthly costs. End-User Computing (Extended) – Theory Page 20 University of Johannesburg Learner Material ©Academic Development Centre 2.4.10 Smart Cards Smart cards look similar to credit cards, but the technology that is contained on the card is not the same. The credit card has a magnetic strip while the smart card contains a microprocessor located under the gold coloured contact image of card. This microprocessor replaces the magnetic strip of the credit card. Image from Google Images 2.5 Input Devices Input devices are used to communicate with the computer. The most common input devices that will be discussed in this section are the keyboard, the mouse (pointing device), touch screen (touch device), scanners, readers, digital cameras and radio frequency identification (RFID). 2.5.1 Keyboard The keyboard controls operations on the screen. The keyboard consists of keys to enter characters on the screen and is used to type letters and numbers like a typewriter.. Keyboards can be built into the computer or attached to your computer using a wired cable. 2.5.2 Pointing Devices Pointing devices are used to move the on-screen pointer to enable the user to open a programme or a document, to play music, or to select functions and buttons displayed on the screen. The mouse is the most common pointing device. The mouse on a computer is like the steering wheel of a car. If you cannot navigate your mouse around the screen area, it is almost impossible to work on your computer. 2.5.3 Touch Devices Touch screens are no longer new technology. Most new smart phone technologies work with a touch screen. With a touch screen device, you can select the commands and provide inputs to the computer by touching the screen to give commands. Examples of touch screen devices include tablets, smart phones, touch pads and desktop computers. Image from Google Images End-User Computing (Extended) – Theory Page 21 University of Johannesburg Learner Material ©Academic Development Centre 2.5.4 Stylus A stylus looks like a small pen. This instrument is used to input commands to a computer screen. With any touchscreen device, a user can just place the stylus on the surface of the screen and draw or make a selection by tapping on the screen. 2.5.5 Scanner The scanner captures images from photos and posters or printed documents and captures them in a digital format. The example alongside is a flatbed scanner that scans flat objects one page at a time. There are also 3D scanners that can scan objects in 3 dimensions. 2.5.6 Barcode Reader A bar code reader is an electronic device that can read and output printed barcodes to a computer. For example, if you purchase an item at a clothing store, the cashier at the counter scans the barcode and immediately the cashier knows the price of the item. The barcode reader consists of a light source, a lens and a light sensor that translate optical impulses into electrical ones. Images from Google Images 2.5.7 Radio-Frequency Identification (RFID) This is the most important development in hardware to support supply chain management. It consists of a circuit that allows information about a product to be recorded. Image from Sousa & Oz End-User Computing (Extended) – Theory Page 22 University of Johannesburg Learner Material ©Academic Development Centre When a tag is attached to a product, it contains an electronic product code. The tag can include the date of manufacture, the plant where the product was made, the lot number, expiry date, destination, and many other details that help track its movement and sale. The information can be read and revised by special RFID transceivers (transmitter-receiver devices). Items with rewritable tags can contain the maintenance history of products, which helps optimise the maintenance of the items. Examples of RFID include access control, where cards are used to replace door keys, and people trackers that are used to track prisoners who are on probation to prevent them from fleeing. 2.5.8 Biometric Readers Biometric readers are based on the science of identifying an individual based on measurable biological characteristics. If you enter the University of Johannesburg, you swipe your student card and then you need to scan your thumb at the biometric reader. The biometric reader will then open the gates only if your thumb characteristics are recognised by the biometric reader. Image from Google Images 2.6 Output Devices Output is the result of data that has been processed by the computer to produce usable information, either on the screen or on paper. Examples of output devices are a printer, your computer screen or a speaker. 2.6.1 Monitor The monitor is the most important output device on the computer. The monitor lets you interact with the computer. If you execute a command, the screen changes as the command is executed. A monitor consists of thousands of tiny dots called picture elements, more commonly known as pixels. Resolution refers to the sharpness and clarity of the images displayed on the monitor. The higher the resolution, the better quality picture you get. 2.6.2 Printer Printers are used to print documents that were typed on the computer onto paper. Printed documents are also called a hard copy. Printers that have more memory can handle much more complex tasks. The different type of printers are dot-matrix printers, laser printers, barcode printers, portable printers (for example, a Zink portable printer) and 3D printers. End-User Computing (Extended) – Theory Page 23 University of Johannesburg Learner Material ©Academic Development Centre The dot matrix printer is the oldest printer around. This printer works on the same concept as a typewriter. It has pins that strike the paper through a ribbon to produce images and letters. Laser printers use a laser beam to produce letters and images on paper. Laser printers are non- impact printers. A barcode printer allows businesses to print custom barcodes for identification or pricing purposes on price tags, shipping labels and other documents. A portable printer is a small printer that you can use on the go, usually with a computer or mobile device. A Zink printer is an example of a portable printer that uses no ink. It uses special paper that is coated with colour dye crystals. 3D printers produce a three dimensional object. They are used, for example, if you are designing a hand for someone who has lost their hand. This type of printing will save costs if you are designing the limb. Image from Google Images End-User Computing (Extended) – Theory Page 24 University of Johannesburg Learner Material ©Academic Development Centre UNIT 3. COMPUTER SOFTWARE INTRODUCTION System software is the main and most important software and is also known as operating software. The operating software is a collection of programmes that manage and co-ordinate the activities that take place in your computer. System software controls all the hardware in the computer and provides a foundation for application software to run on. Any house needs a foundation before the walls can be built; the same concept applies to computers - they need an operating system to run on. Every time your computer is switched on, the operating system will be loaded into your RAM, which will get your computer ready to be used. After the programmes are loaded, the operating system provides you with access to your application software and ensures that all the actions requested by the user are valid and processed in an orderly way. OUTCOMES At the end of the unit you will be able to:  Discuss computer software ASSESSMENT CRITERIA You will be deemed to be competent if you can:  Explain system software and operating systems.  Identify operating systems for personal computers.  Identify operating systems for mobile devices and larger computers.  Describe common types of application software.  Describe application software used for businesses. (Source: Pinard, Romer and Morley) 3.1 Functions of an Operating System The functions of an operating system can be divided into four major functions, which are as follows:  An operating system can be seen as the middle man between the user and the computer, as well as between the application software and the computer hardware. You cannot run any application software programmes such as Microsoft Office without an operating system.  If you connect any hardware device to your computer, the operating system will configure it before it will allow you to use the device. End-User Computing (Extended) – Theory Page 25 University of Johannesburg Learner Material ©Academic Development Centre  The operating system communicates with all the hardware devices that are connected to your computer, for example, your monitor, printer, portable storage devices, keyboard and mouse.  The last function, but an important task if you are working on a computer, is the storage of your files. The operating system allows you to manage your files. This involves keeping track of the files stored on your computer and makes it easy for you to retrieve your files from the computer. 3.2 Differences Between Operating Systems The operating system uploaded to your device will depend on the needs of the user. Most operating systems today use a graphical user interface. This means that the user uses icons or commands on the screen to issue instructions to the computer. If you think of the Microsoft environment, you will remember that you used icons on the ribbon to command the computer to bold your text. The older DOS operating system uses a command line interface, which requires the users to type commands to issue instructions to the computer. There are four different types of operating systems namely: 1) personal operating systems, 2) server operating systems, 3) mobile operating systems and 4) embedded operating systems. The personal operating system is designed to be installed on a single computer. The server operating system is designed to be installed on a network server to grant multiple users access to a network and its resources. The mobile operating system is designed specifically for smartphones and other mobile devices. The embedded operating system is a specialised operating system for use in computers built into larger systems. It can be built into consumer kiosks, cash registers, cars and other devices. 3.3 Types of Operating Systems There are a variety of operating systems available for personal computers, network servers and mobile devices namely:  DOS  Windows  Windows Server and Windows Home Server  Mac OS and Mac OS X Server  UNIX  Linux (Source: Pinard, Romer and Morley) Mobile operating systems include:  Android: Linux-based, built from the ground up  iOS: designed for Apple mobile phones and mobile devices End-User Computing (Extended) – Theory Page 26 University of Johannesburg Learner Material ©Academic Development Centre  BlackBerry OS: designed for BlackBerry devices  HP web operating system: Linux-based, developed for palm mobile phones  Symbian OS: use has been declining 3.4 Application Software Application software is software that solves a specific problem or performs a specific task. If you need to type a letter, you will use MS Word, and if you want to create slide shows for a presentation, you will use MS PowerPoint. There are four categories of ownership rights for application software, namely:  Commercial software: this means the software programme is developed and sold for a profit. In other words, you are not allow to upload it onto your computer without paying for it, for example, MS Office.  Shareware: this software programme is available free of charge but may require a small registration fee, for example, WinZip.  Freeware: these software programmes are given away for free by the developer, for example, Chrome, QuickTime player.  Public domain software: this type of software programme is not copyrighted, for example, Lynx. 3.5 Desktop vs Mobile Software Desktops, notebooks and other portable computers normally use the same application software. Smartphones and other mobile devices use mobile applications that are designed for a specific type of mobile device and operating system. Some mobile applications are designed to be compatible with popular software, such as MS Office, so that documents can be shared between the two platforms. 3.6 Application Software for Businesses Related software that is bundled together, for example Microsoft Office, is referred to as a suite. The primary advantage for businesses who buy software suites is that the total cost of the suite is lower than the cost of buying the programmes individually. The Microsoft Office suite includes MS Word, which allows you to create and edit complex documents. It also includes MS Excel, which is spreadsheet software that allows the user to create a workbook that contains complex mathematical calculations. MS Access is database software that allows you to sort and organise vast amounts of data and retrieve specific information when needed. MS PowerPoint is presentation software which allows you to create visual presentations that include graphics. End-User Computing (Extended) – Theory Page 27 University of Johannesburg Learner Material ©Academic Development Centre COMPUTER NETWORKS INTRODUCTION A network is a collection of computers and other devices that are connected to one another in order to share hardware, software and data, as well as to communicate electronically. This means that you can share your data and communicate electronically through the networks and the internet with all any person or system anywhere in the world. OUTCOMES At the end of the unit, you will be able to:  Discuss computer networks ASSESSMENT CRITERIA You will be deemed to be competent if you can:  Explain what networks are.  Identify network characteristics.  Understand how data is transmitted over a network.  Describe common types of networking media.  Identify protocols and networking standards.  Describe networking hardware. (Source: Pinard, Romer and Morley) 4.1 Business Use of Computer Networks In today’s technological age it would be difficult to imagine business without computer networks. Think of the vast opportunities for businesses to communicate with other businesses around the world. With the different networking applications such as videoconferencing available for businesses, a CEO does not need to travel around the world making business deals. Videoconferencing allows two or more participants at different sites to conduct a conference using computer networks to transmit audio and video data. For example, the CEO can conduct real-time, face-to-face meetings with other businesses around the world. Videoconferencing can take place via personal computers or even mobile devices. If there is going to be a panel discussion with the top management of two Image from Google Images End-User Computing (Extended) – Theory Page 28 University of Johannesburg Learner Material ©Academic Development Centre companies, then both companies will make use of videoconferencing rooms where individuals appear life-size, as shown in the picture alongside. 4.2 Personal Use of Computer Networks Computer networks allow families to share resources, access the internet and communicate with others in their homes. By having personal computer networks people can work and access their work e-mails from home. 4.3 Network Characteristics There are a variety of network characteristics such as wired or wireless, topology, speed, cost, security, availability, scalability and reliability. 4.4 Wired vs Wireless Network A network can be designed for access via wired or wireless connections. A wired network will require your computer to be connected via a network cable to the network. A wireless network is connected through radio signal waves that are used to send data through the air between devices. An example of a wireless network is the network that we use to connect to cell phone providers using smartphones. Sometimes you can use “wireless hotspots”. For example, you can connect to the wireless network at an airport if you are travelling abroad/overseas and you cannot access your cell phone network abroad/overseas. 4.5 Network Topologies Topology is the layout pattern of the interconnections between computers in a network. The three most common topologies are the star, bus and mesh. The star network is the most common computer topology. The topology of this network forms a star as illustrated in the diagram alongside. The star consists of one central network device called the hub, which acts as a channel to transmit messages to the computers connected to the hub. If the central hub fails, then the network cannot function. End-User Computing (Extended) – Theory Page 29 University of Johannesburg Learner Material ©Academic Development Centre The bus network is a topology where all the computer devices in the network are linked to one another through a single cable or line. The network acts as a central cable to which the network devices are connected. The data are then transmitted down the bus line from one computer device to another computer device. If the bus line fails, then the network cannot function. Image from Google Images The mesh network uses a number of different connections between the network devices. This means that the data can take several possible paths from one source to its final destination. The mesh network can still function if one device on the mesh network fails. A mesh network is often used with wireless networks. Image from Google Images 4.6 Network Architecture Network architecture is the design of a communication network. It is the framework of an organisation’s computer network. It provides a full picture of an organisation’s established network, with a detailed view of all the resources that are accessible. These resources include the hardware, software, connectivity, communication protocols and mode of transmission (which can be wired or wireless). The two most common network architectures are the client- server network and the peer-to-peer network. A client server network has a powerful centralised server (hub) to which many personal computers, called the clients, are connected. The Vodacom network is an example of a client server network. The host is any computer or smartphone that is connected to the Vodacom network. End-User Computing (Extended) – Theory Page 30 University of Johannesburg Learner Material ©Academic Development Centre A peer-to-peer network is not a server-based network, as the computers that use the network, connect directly to one another. It is a decentralised platform where two or more computers are linked without a third party and can share information. A peer-to-peer network does not have a central server. Each computer acts as a server for the stored files. A peer-to-peer network can use the internet but a central server can then be Image from Pinard, Romer and used to index the files. Morley Example: Peter wants video X and goes on the P2P Network to send a request to other users on the P2P network for a copy of video X. Some of these individuals on the P2P Network may possess video X. Peter has video Y on his computer that he can share with other users on the P2P network. Users on the P2P network share material. Thus, Peter will allow other users to download video Y from his computer, and other users will allow Peter to download video X from them. Therefore, users share material by sharing files as needed. This is called file sharing on P2P. 4.7 Network Sizes and Coverage Areas Networks can be classified according to their size and their coverage area. In this section, we will look at the most common categories of networks, namely, personal area network (PAN), local area network (LAN), metropolitan area network (MAN), wide area network (WAN), intranet, extranet and virtual private network (VPN). A personal area network (PAN) consists of personal devices that are connected to one another. These personal devices can only be connected within a range of 10 metres. An example of a PAN is when your laptop, smartphone, tablet, smart watch and printer are connected to one another. A local area network (LAN) is a network of computers set up in a building or on a campus. The network only operates in that specific building or on that campus. The characteristics of a LAN are that it is located in a specific building, is inexpensive, has a high speed data rate and low error rate, and no telephone lines are required. A metropolitan area network (MAN) is a network that works in a metropolitan area, typically in a city or a country. MANs are owned and operated by a city or country. The network for the Johannesburg metropolitan area is an example of a MAN A wide area network (WAN) is a network that can connect any number of computers anywhere in the world. This is done by using a telephone line and a large server and network protocols. The characteristics of a WAN is that it can connect anywhere in the world, it is expensive, has End-User Computing (Extended) – Theory Page 31 University of Johannesburg Learner Material ©Academic Development Centre a low to moderate speed data rate and error rate, and it requires telephone lines and network protocols. An intranet is a private company internet that is designed to be used by the employees of the company. It is set up like an internet with data posted on Web pages that are accessed using a web browser. An intranet can only be accessed if you are connected to the company network, for example, UJ employees can only access the UJ intranet if they are on one of the four campuses. An extranet on the other hand, is a network that is accessible by authorised outsiders and it is usually accessed via the internet. For example, the UJ extranet provides former UJ students with the opportunity to access the extranet to find any data they need about UJ. The intranet and extranet are restricted to employees and other authorised users. A virtual private network (VPN) is a network that allows you to stay anonymous online and secure your web traffic. If you connect to a VPN, your network traffic passes through a protected tunnel and no-one can see your traffic. To stay secure, you need to make sure that you connect to websites with https: because your data will then continue to be encrypted, even after you have left the VPN. 4.8 Data Transmission Think of data transmission as data communication but in a digital way. This means that the data is transferred from one point to another. Data transmission has various characteristics, namely bandwidth, analogue vs digital signals, transmission type and timing, and the data delivery method. Bandwidth refers to the amount of data that can be transferred from one point to another in a given timeframe. The higher the bandwidth, the faster the data will travel from one point to another. If you compare a fire hose with a narrow garden hose, the fire hose will allow more water to pass through than the narrow garden hose. Bandwidth works on the same principle: the higher the speed of your bandwidth, the faster the data will move. Data can be represented in two ways, namely in analogue or digital signals. For example, voice and music data in their original form use an analogue signal. The data that you store on your computer is digital. Digital data is represented in two discrete states, namely 0s and 1s. An analogue signal is a radio frequency that works on the principle of encrypting data in the form of radio ANALOGUE signals. Various types of encryption can be used to encode data in the radio signals. One type is encoding data by varying the amplitude of the radio signal. The lower the frequency, the more penetration the signal has and the longer the antenna used to receive the signal. Short antennas are used for higher frequencies – for example, cell phones use high frequency and therefore have a short antenna and signal bandwidth. End-User Computing (Extended) – Theory Page 32 University of Johannesburg Learner Material ©Academic Development Centre Radio frequency can be used to encode data and transmit the data via the radio frequency network. DIGITAL Digital signal is a coding protocol to encode data in the radio frequency to allow for transmission of data. The digital signal is highly reliable. The encoding of data can be done by changing the frequency or amplitude of the frequency wave in various ways. One such technique is digital Image from Google Images encoding. Digital values are encoded in a “1” position, which in an on, or a “0” when the switch is in an off state. The square wave pattern shows only an on or off phase related to a 1 or a 0. The signal is either on or off in terms of proposed digital values of 0 and 1. Parity bits of zero or ones are included in bytes. There are two methods which are used to transfer data between computers, namely serial or parallel transmission. Serial transmission is where data is sent bit by bit, while parallel transmission sends a byte (8 bits) or one character at a time. In other words, if you send a message using serial transmission, only one bit is being sent at a time, but if you use parallel transmission then one character is being sent at a time. There are three methods by which data can be delivered, namely, circuit switching, packet switching and broadcasting. Circuit switching is when a dedicated path between the sender and the receiver is established over a network. Packet switching occurs when the message is separated into small units called packets. The packets contain information about the sender and the receiver. When these packets reach their destination, they are restored into the proper order. Broadcasting also sends data out in packets to all nodes on the network. The data is only received by the intended recipient, based on data transmission on a local area network, such as a small business that also wants some security in place, using a dedicated LAN network. Images from Google Images End-User Computing (Extended) – Theory Page 33 University of Johannesburg Learner Material ©Academic Development Centre 4.9 Wired and Wireless Networking Wired networks use a physical cable to connect between two points. For example, a telephone is connected to an exchange using the Public Switching Telephone Network (PSTN) which is managed by Telkom. There are various types of cables used such as copper, coaxial and fibre optic. These cables are physically connected and need to be joined to interconnect the network or communication platform. Copper cables need to be maintained and repaired, and are often vandalised and stolen. This has forced communication companies to move to alternative ways of proving communication services to clients such as wireless networks, such as GSM (Global System for Global Communications), or cell phone communication. There are three different wired network transmission cables, namely: - twisted-pair: physical copper cable consists of two thin copper wires that are twisted together - coaxial: a core of solid thin copper cable is covered by a plastic isolation and copper mesh shield, and - fibre optic cables: cable with shielding that contains a micro glass tube in a shielded cable to relay data using light to transmit data. Images from Google Images A coaxial cable is used for high speed radio frequency communication such as the physical relay of television or DSTV signals from a dish to a television set, decoder or related devices. A fibre-optic cable is a high speed cable manufactured by placing a micro glass tube into a shielded cable to protect the glass tube that relays data using light to carry signals. These cables End-User Computing (Extended) – Theory Page 34 University of Johannesburg Learner Material ©Academic Development Centre are connected to residential, business and other data infrastructure to allow for high speed data communication. Physical cables are traditional physical cables that carry data from one point to another. There are different types of cables that are used to transmit various types of data or signalling types. High levels of theft of these physical cables and the need for faster speeds for data transmission has forced telecommunication service providers to look at alternative technologies to transfer data. Wireless networks use non-physical connections to transmit data and connect devices. Wireless networks such as GSM are used to transmit data via cell phone Image from Google Images networks. Inside a business, a physical cable is used to distribute the data signal throughout the business using a switch to distribute the signal to various computer users within the business. The different computers within the business are connected using physical data cables. However, if no physical cable network is available, a WiFi network, which is based on a WiFi router configuration, can be used as an alternative connection method. The WiFi network doesn’t need physical connections to connect the computers within the business as it uses a wireless signal to connect the various computers, without physically connecting to device. This technology doesn’t have the disadvantage of theft and the high cost of aging infrastructure that requires continuous repairs and maintenance. Wireless networking can be exploited, resulting in the network being compromised. These wireless networks are exposed to hacking attacks which access personal data without the owner’s authority. Encryption is used as cybersecurity in this technology but has limited effectiveness. 4.10 Communications Protocols and Networking Standards Networks are the foundation of the internet if you look at the internet as a major network. In order for the network to work and allow effective communication, specific rules and principles need to be adhered to. As the internet communicates via packets of data that are sent during communication on the internet, these packets need to be packaged and distributed according to specific protocols and standards. These transactions vary from encrypted data to email messages. Computer protocols have evolved over time and have led to various communication types on the internet. The protocols are a set of rules to share or distribute data via communication networks. They are essential to digital communications and a multitude of protocols exists. Examples of the main protocols on the internet are IP (Internet Protocol), FTP and HTTP. TCP/IP and other communications protocols (http, https, FTP, SMTP, and POP3) are used to standardise communication on internet platforms for the purpose of data transmission. These protocols guide various communication devices to share data in a way that these devices can interpret data and are able to process data correctly as needed by the user. These protocols End-User Computing (Extended) – Theory Page 35 University of Johannesburg Learner Material ©Academic Development Centre allow packets of information to flow and are guided by the type of device being used or data being shared. They entail synchronisation and verification, with the purpose of detecting any anomalies and to ensure that data is correctly routed, be it hardware or software driven. Routing protocol is part of web page browsers such as Google. As previously discussed, all communication is based on data that is encoded into packets based on 1s and 0s. 1s and 0s are binary values and eight 1s and 0s are called a byte. Authentication protocols are crucial as they allow for the signalling and the synchronisation of data communications. Protocol values may include handshake, packet speeds and sizes, the routing of packets and addressing information Examples of the various protocols include:  TCP/IP: This protocol is a well-known and open protocol that is widely used to transfer data. It consists of various layers based on a physical connection within the communication architecture. Various hardware and software devices use this protocol to connect with the purpose of transferring data. Web browsers use this protocol for communications.  HTTP: Hypertext Transfer Protocol application relates to the internet, and is used by webpages including HTML (Hyper Text Markup Language). HTML files consist of coded text files.  HTTPS: Hypertext Transfer Protocol Secure is a protocol used to secure or lock down websites. It is associated with personal or banking information. Users need to ensure that personal data is only shared on websites displaying the letters https in the URL, for example https://netbank.nedsecure.co.za  FTP: File Transfer Protocol refers to FTP servers used for the storage of data and access to data when needed by users. This is not a secure platform.  SMTP: Simple Mail Transfer Protocol refers to outgoing email communication server settings.  POP3: Post Office Protocol is used for incoming email communication server settings. Ethernet (802.3) - Ethernet is the most widely used standard for wired networks. Ethernet is also a protocol standard that is part of local area networks, network geographical locations and physical positions, and standardising physical networks using physical cables such as copper, coaxial and fibre optic. Phone line, power line, G.hn, and Broadband over Power line (BPL) – are the alternatives to the Ethernet standard for wired home networks. Phone lines or power lines can be used to replace a communication architecture network that is not available in certain areas. They are also referred to as an EOP Ethernet or power network. Most rural areas don’t have a copper or telephone network available for internet access. To compensate for this, BPL technology became available to allow internet connectivity using the existing power supply from the municipality as received from ESKOM. The principle of End-User Computing (Extended) – Theory Page 36 University of Johannesburg Learner Material ©Academic Development Centre the technology is to provide access to the internet by creating channels on the network or power cable connection. Broadband uses low frequency electric signals for audio communications, for example speech, while the higher frequency is used to transmit internet data. To distinguish between the signals, voice communication is encoded on a low frequency and data is encoded using a high frequency as a high speed connection. WiMAX (802.16) - WiMAX (802.16) is a series of standards designed for longer range wireless networking connections. Mobile WiMAX is the mobile version of the WiMAX wireless networking standard. This network standard is focused on a fixed broadband solution for wireless networks, based on fixed and wireless networks. Cellular communication based on GSM (global system for mobile communication) provides the communication infrastructure for internet connectivity and various forms of data communication via the GSM protocol. Cellular communication is based on radio frequency communication and, since radio signals only travel short distances, the signal needs to be received, made stronger and then sent further. The resend function is performed by a repeater and attenuators that relay the cellular communication within the various cellular network providers. Network providers in South Africa are MTN, Vodacom and Cell C. If you are travelling in rural areas next to highways, cell towers with repeaters to repeat signals can be seen next to the road about 30 km apart. Bluetooth, Ultra-Wideband (UWB), and other short-range wireless standards - A mobile phone can connect to a Bluetooth headset even when the phone is in your pocket. Short distance wireless networks allow short distance connections to the internet and the sharing of data. These distances can be up to a couple of metres and are designed for connections that are in close proximity to the source of the network. However, they are wireless as no physical connection is made between devices. Short distance protocols or standards are near field communications, Bluetooth and infrared connections. Data is transmitted via a radio communication network based on wireless network principles, connecting smartphones, speakers and printers using a high frequency. Infrared light (IR), such as night vision technology, uses a very high frequency band 4.11 Networking Hardware End-User Computing (Extended) – Theory Page 37 University of Johannesburg Learner Material ©Academic Development Centre Networking hardware consists of various hardware devices that are combined to construct an effective and working internet service by allowing the flow of data packets that are the backbone of internet communications. The different networking hardware types are well known and consist of routers on the network that are responsible for the routing of data traffic on the network. Image from Pinard, Romer and Morley These networks are accessed by computers that need to access the network and require a specific interface, referred to as the network card, to communicate with the associated router, be it wireless or not. The routers in the network are supported by switches which copy data to the relevant port for communication. Wired networking occurs when Ethernet cables transfer data between the network and the connected computer. Network hardware connects the various devices on a computer network for the purpose of data transmission. Hardware devices are different and put in place for specific functions. The functions that the devices need to provide are based on the system design and what system needs to provide. Some of the network devices that form part of the network are the network interface card, the switch, router and bridge. These devices have different functions and roles to play in the transmission of data, and they are crucial to the functioning of the network. The router processes packets of data that route data appropriately. Network adaptors are hardware components that facilitate communication via the specific network architecture modules. These individual devices are all connected to form a complete network architecture for communications. Network interface cards are the connection modules between each computer and the network that facilitate data transfer. Switches are another type of module that function as intermediaries between the switch and the router modules. These modules, including routers, make connections between networks possible. Other Networking Hardware is used to set up and deploy networks for data communication. These network hardware modules are used to control network connectivity and traffic via the network, and they differ according to the unique criteria of the network architecture. Each individual module or device has a unique function and capacity within the network. The network architecture and cabling set-up is referred to as the system topology. The system topology dictates which network hardware will be deployed to allow for connectivity and data End-User Computing (Extended) – Theory Page 38 University of Johannesburg Learner Material ©Academic Development Centre transfer for communication and file sharing within the network to provide needed services. The network coverage is also considered. End-User Computing (Extended) – Theory Page 39 University of Johannesburg Learner Material ©Academic Development Centre UNIT 4. THE INTERNET INTRODUCTION The internet is a worldwide network that is a collection of separate but interconnected computer networks around the world. The internet is accessed by billions of people worldwide. Over the past two decades, the internet has evolved and redefined how we think about computers, how we communicate with each other and how we share information. OUTCOMES At the end of the unit, you will be able to:  Describe what the internet is. ASSESSMENT CRITERIA You will be deemed to be competent if you can:  Understand how the internet evolved.  Set up your computer to use the internet.  Understand how to search the internet for information. (Source: Pinard, Romer and Morley) 5.1 Evolution of the Internet In 1969, the United States Department of Defense Research Project Agency (DARPA) created an experimental project called ARPANET. ARPANET was the forerunner of the internet and started with only 4 computers. The networking protocol used by ARPANET was the Network Control Program, which was replaced with the TCP/IP protocol in 1983. This protocol quickly became the most widely used network protocol in the world. ARPANET was transferred to the NSFNET in 1990. NSFNET was soon connected to CSNET, which linked universities in North America. It was then connected to EUnet, which connected research facilities in Europe. After 1990, the internet exploded because of the popularity of the web, and today more than a billion people use the internet. End-User Computing (Extended) – Theory Page 40 University of Johannesburg Learner Material ©Academic Development Centre Image from Google Images In 1989, the English scientist Sir Tim Berners-Lee invented the World Wide Web. By 1990, the first web browser computer programme was written by him while he was employed at CERN in Switzerland. Sir Berners-Lee wrote three fundamental technologies, namely Hypertext Markup Language (HTML), Uniform Resource Identifier (URI) and Hypertext Transfer Protocol (HTTP). HTML is the mark-up (formatting) language for the web. The URI, also referred to as a URL, is the unique “address” that is used to identify each of the resources on the web. HTTP allows for the retrieval of linked resources from across the web. Remember: It is important to keep in mind that the internet is not the web. The internet is a physical network and the web is a collection of web pages that are accessible using the network. Image from Google Images 5.2 Connecting to the Internet To connect to the internet there are three decisions that you need to make: 1) Determine the type of device that you would like to connect from. 2) Decide on the type of connection, and then 3) Select the internet service provider you want to use. After making these decisions you will be connected to the internet. 5.3 Selecting the Type of Device End-User Computing (Extended) – Theory Page 41 University of Johannesburg Learner Material ©Academic Development Centre In today’s technological age, you can access the internet from various devices, namely the personal computer, smart phones, tablets and smart TVs. Your need will determine which device you will use to connect to the internet. 5.4 Choosing a Type of Internet Connection To access the internet, you first need to connect your computer or device to it. The most common type of internet connections used today are as follows:  Conventional dial-up: Dial-up via standard telephone lines  Cable: Fast, direct via cable TV lines  DSL: Fast, direct via standard telephone lines  Satellite: Fast, direct via the airwaves and a satellite dish  Fixed wireless internet access: Fast, direct, available in some areas via the airwaves  BoF or FTTP: Very fast, direct via fibre-optic networks  Mobile wireless internet access: via a mobile phone network  Wi-Fi hotspot: Location with a direct internet connection and a wireless access point 5.5 Selecting an Internet Service Provider (ISP) An internet service provider is defined as any network that provides connectivity to the internet and may include the Wi-Fi distribution network of a private citizen. The ISP hosts the network connection platform and provides the internet service to clients. The main ISPs in South Africa are Telkom, Vodacom, MTN, Cell C, Internet Solutions, Hetzner and MWEB. 5.6 Set Up your Computer to Use the Internet You need to use a search engine to access the internet. Network connectivity is crucial, and if no such data link or connection exists, no search or access is possible. The internet is accessed using various browsers such as Safari, Mozilla Firefox, Opera and Chrome. When double- clicked, the browser will open and connect to the internet if such a service is available on the computer. When the browser opens, a URL value can be typed into the top bar of the browser selected by the user, such as Yahoo, Google and Bing etc. These search engines will be guided by information typed into browser information bar. These searches need to be done in a proper manner and, if certain websites are visited, they may contain malicious software. This malware may be disguised as a picture or update and, when clicked on, may result in the computer being compromised. The internet is a wonderful platform with a multitude of information and services. However, man