1.1 General model of a computer | Basic concepts of computing | Siyavula

CHAPTER OVERVIEW

Learning outcomes

At the end of this chapter you should be able to:

• define Information and Communication Technologies (ICTs) and Information Technology
• provide an overview of a general model of a computer
• provide an overview and concepts of the main components of a computer system
• define shareware, freeware, free open source software (FOSS) and proprietary software
• explain the interdependency of hardware and software
• state and differentiate between the types of computers
• categorise computers/classification of computers
• list the advantages and disadvantages of using computers
• explain and differentiate between data and information
• explain the information processing cycle
• provide an overview of uses and examples of information within an organisation
• explain why is information useful
• provide an overview of a general model of an ICT system.

New words

input device – any hardware or peripheral device that allows you to enter data into a computer or interact with a computer

storage device – a hardware device that is used for storing data

random-access memory (RAM) – a hardware device, usually on the motherboard, that allows information and data to be temporarily stored and retrieved on a computer while it is on

processing device – a hardware device that receives the data, performs a set of instructions, and then returns the processed data to the RAM

output device – a device that formats and presents data in a form understandable to a user

communication device – a hardware device capable of transmitting a signal over a wire or wireless connection.

INTRODUCTION

Information Communication Technologies (ICT) is the combination of computer-based technologies (such as computing devices and smartphones) with communication technologies (such as telephones, cell phones and the internet). In practice, it refers to all the hardware, software, and systems essential to communicate electronically.

Over the last twenty years, the field of ICT has grown from a small niche field to one of the most important fields in the world. Refer to the YouTube video to see how ICT has changed over the years.

HOW ICT HAS CHANGED OVER THE YEARS

Short Link

UNIT

1.1

General model of a computer

In this unit, you will:

• define Information and Communication Technologies (ICTs) and Information Technology
• provide an overview of a general model of a computer
• explain the information processing cycle.

ICT SYSTEMS AND IT

Information and Communication Technologies (ICT) refers to technologies that capture, transmit and display data and information electronically and includes all devices, applications and networking elements that allow people to connect in a digital world.

An ICT system refers to the overall set-up, consisting of hardware, software, data and its users. ICT systems as a whole include:

• People – to supply the data and to make decisions from the output supplied from the system information, which is based on the results from processing data and the output from an ICT system.
• Hardware e.g. input devices, storage, processor, output devices and communication devices.
• Procedures – to determine what needs to be done and when. This causes the passing of data or information between people.
• Software – the computer programs which provide the step-by-step instructions to complete the task.
• Data – raw material that is processed by the system to provide the information for the output provided by the system. Data can come in different formats, such as sounds, images, and videos, etc.

In order for an ICT system to function, it needs to receive, store, retrieve, manipulate and transmit data.

Computers are programmable electronic devices designed to accept data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations. Computers are used in Information Technology (IT) – which is a subset of ICT. Computers store, transmit, retrieve and manipulate data for businesses and other enterprises. Computers refer to the hardware, and since computers cannot initiate functionality on their own, they start functioning as soon as they receive data to work with (to process). This data is then stored on the computer, the computer manipulates the data according to the instructions it has received, before sending the new information back to the user.

Thus, we can say that Information technology (IT) is the development, maintenance and use of computer systems, software, and networks for processing and communicating data.

THE GENERAL MODEL OF A COMPUTER

The following illustration demonstrates a general model of a computer and shows that the functions of a computer are similar to the steps of the information processing cycle. All basic computers consist of four functions: input, storage, processing and output.

Figure 1.1:

The general model of a computer

IPO is often called IPOS or input, process, output, storage. The computer receives input, processes the input as per user instructions and provides output and can be stored in a desired format.Computer input is called data and the output obtained after processing it, is called information. Raw facts and figures that can be processed using arithmetic and logical operations to obtain information are called data.

The general model of computers can be used to explain how each computer (or smartphone) works.

Once you understand how a computer operates, it becomes a lot easier to think about creating your own programs. When you begin learning about coding a program, you need to understand that you must create a set of step-by-step instructions that manages the flow of information: from when your program receives data from the user, up to the point when it returns output back to the user.

Activity 1.1

1.1.1Differentiate between ICT and IT.

1.1.2List the output devices of your computer.

1.1.3Follow the guidelines below to provide a diagrammatic example of the general model of computers.

a.Draw a diagram of the five steps of the general model of computers.

b.Define each step.

c.Think about when you send a WhatsApp message. How can you apply the general model of a computer to this?

Hint: Watch the video given in the QR code to help you answer this question.

INTRO TO COMPUTER ARCHITECTURE

UNIT

1.2

Hardware and software

In this unit, you will learn about the following:

• provide an overview and concepts of the main components of a computer system
• define shareware, freeware, free open source software (FOSS) and proprietary software
• explain the interdependency of hardware and software.

HARDWARE VS. SOFTWARE

For a computer to function properly, it must consist of both hardware and software, because the hardware and software are interdependent. This means that the one will not function without the other.

• Hardware consists of the physical components of a computer, also referred to as the equipment of a computer. Hardware devices can be categorised according to their functionality on the computing device.
• Software Application software (Apps) and System software (Operating System ) refers to the programs used to direct the operation of a computer. It also contains the instructions for how to use the software.

HARDWARE: THE PHYSICAL COMPONENTS OF A COMPUTER SYSTEM

The common physical components of a computer system that will be discussed are input (keyboard, mouse), storage (hard drive), memory (RAM), processing (CPU), output (monitor, printer) and communication (Network Interface Card, NIC).

• Input devices are any hardware devices that allows you to input data into a computer or interact with a computer. In the past, the most popular input devices included the mouse and keyboard. These days, however, there is quite a variety of input devices. One very popular example is the touchscreen keyboard on mobile smartphones.
• A storage device is a hardware device that allows you to store data for later use. There are many different storage devices, with each device having advantages and disadvantages. Some of the most popular storage devices include hard disk drives (HDDs) and solid-state drives (SSDs). The different storage devices will be discussed in more detail in later chapters.

Figure 1.2:

The touchscreen is a popular input device

Figure 1.3:

Hard disk drives mostly have large storage capacities

• Random-access memory (RAM) refers to a fast, temporary form of storage. All data and instructions that is currently being executed is stored in RAM. RAM is volatile, that is, all data is erased from your RAM when your computer is turned off. RAM is also referred to as memory.

Figure 1.4:

Random-access memory (RAM)

• Processing devices receive the data from the RAM, perform sets of instructions, and returns the processed data to the RAM. The two most important processing devices in modern computers are:

• The Central Processing Unit (CPU) is responsible for processing general instructions. Every application makes use of the CPU to collect, decode and execute instructions as required by the application.
• The Graphics Processing Unit (GPU) is responsible for processing the instructions that create the pictures on your screen, for example, three-dimensional games rely heavily on the GPU to create their images.

Figure 1.5:

The CPU contains the necessary circuitry to interpret and execute program instructions

• Output devices are devices that return the computer’s instructions, as results, to the user. Popular output devices include monitors / screens and printers.

Figure 1.6:

A laptop computer with a second screen connected

Take note

Do not mistake the screen of a computer for the computer itself! In many films, actors destroy the screen of a computer to destroy the computer. In most situations, the computer would continue working without a screen and users would be able to use the computer as soon as a new screen is connected.

• A communication device is a hardware device capable of transmitting an analog or digital signal over a wired or wireless connection. Examples include, a modem and a network interface card (NIC) that can be either wired or wireless

SOFTWARE: THE NON-PHYSICAL COMPONENTS OF A COMPUTER SYSTEM

Software refers to the set of instructions a computer uses to complete any instructed task. Software is the program that is operated by the hardware. These include programs such as, Microsoft Applications or InDesign Creative Suite. As a result, hardware and software are interdependent.

Remember that this interdependence means that neither the software nor the hardware can function without the other one. Hardware cannot do anything without software because it depends on the processed instructions to provide input, while software cannot function without hardware to process the user’s instructions.

Figure 1.7:

Software refers to instructions that a programmer has created for hardware

The two most important types of software are:

• system software (including the operating system)
• application software.

Did you know

One of the primary outcomes of this subject is to teach you how to write your own software. This will allow you to use the power of a computer to make your life, and the lives of the people all around the world, better and easier!

You will learn more about the different types of hardware and software and the relationship between them.

SYSTEM SOFTWARE

System software is the specific type of software that manages the flow of data and the information contained on the computer. The operating system (OS) is the most important type of system software.

Examples of operating systems include Microsoft Windows, Linux, MacOS, iOS and Android. The OS is designed to control and coordinate the tasks and functions of computer hardware.

APPLICATION SOFTWARE

Application software is a program that is built for a specific purpose, like sending a message, browsing the internet, or typing a document. Application software refers to any software that lets the user accomplish a function or create content. Application software requires system software in order to function. This type of software includes media players, spreadsheets and word processors. When multiple applications are packaged together it is called an application suite. Examples include Microsoft Office, Google Chrome, Mozilla Firefox and Skype. Games and mobile applications such as Spotify and Uber, are also considered application software.

SHAREWARE, FREEWARE, FREE OPEN SOURCE SOFTWARE (FOSS) AND PROPRIETARY SOFTWARE

Let’s have a look at the table on the next page. The table shows the differences and uses between shareware, freeware, free open source software (FOSS) and proprietary software.

When a program is developed, the developers decide whether the code is proprietary or open source software (OSS). The table below explains more about open source software.

Take note

Keep in mind that there are safety precautions you should follow when downloading free or paid software. Nothing stops the developer from bundling the software with malicious software, malware (virus, worms, or spyware) and still make you pay for it. There is also a lot of freeware that is useless or ineffective and you need to be aware of the importance of practicing good software safety, so that you can choose the best software for your needs.

WHAT IS OPEN SOURCE SOFTWARE

Activity 1.2

1.2.1Explain the difference between hardware and software.

1.2.2Explain the interdependency of hardware and software.

1.2.3Match column A with column B. Only write the question number and the alphabet letter, e.g. 1, M:

1.2.4a.Differentiate between system software and application software.

b.List two examples of operating systems.

c.List two examples of application software.

1.2.5a.Define shareware, freeware, free open source software (FOSS) and proprietary software.

b.Evaluate which categories given in question 1.2.4 a. above would most likely be used for the following:

i.a gamer

ii.a businessman who has online meetings

iii.a student researching for a project

iv.a teacher designing lesson plans

1.2.6a.Distinguish between the six main components of a computer system.

b.Provide an example for each of the main components of a computer system.

1.2.7What is a storage device? Give examples of those that you have in your computer lab.

1.2.8Read the following article taken from an eNCA report and answer the questions that follow.

Subdued growth to dominate SA’s ICT market

By KAUTHAR GOOL

Johannesburg, 15 Feb 2018

South Africa’s overall ICT market is expected to reach $21.4 billion (R248 billion) by the end of 2018, and $23.4 billion (R273 billion) by 2021, representing a compound average growth rate of 2.9%.

This is according to market research firm IDC, which hosted its IDC Directions 2018 event in Johannesburg this week.

Speaking at the event, Mark Walker, associate vice-president for Sub-Saharan Africa at IDC, said this is in line with overall macro-economic growth expectations which are relatively subdued.

According to Walker, IT services, software and infrastructure roll-out are the fastest growth segments in SA’s ICT market.

‘The government and financial sectors dominate spend in South Africa,’ he noted. ‘In finance, this is driven by investment in upgrading legacy systems, compliance, as well as risk mitigation and improving customer experience.’

He pointed out that government spend is focused on maintaining and upgrading existing systems while rolling out infrastructure and improving connectivity as progress is made on various discrete smart city initiatives.

[Source: https://www.itweb.co.za/content/xnklOvzbkd8v4Ymz [Last accessed April 2019]]

a.ICT and IT are mentioned in the excerpt. Explain and describe the difference between these terms.

b.The term ‘legacy systems’ is used in the text. Research this term and explain its meaning in your own words.

c.Explain what in meant by ICT infrastructure.

d.What is meant by connectivity in this context?

UNIT

1.3

Types of computers

In this unit, you will:

• state and differentiate between the types of computers
• categorise computers/classification of computers.

Wouldn’t it be fantastic if each morning, 10 minutes before your alarm goes off, your coffee machine automatically pours you a cup of coffee, tea or hot chocolate, your toaster makes fresh toast, your lights slowly turn on and music starts playing?

Less than 15 years ago these concepts could only be found in science fiction films. Today, thanks to the development of affordable computers, all these smart devices exist and are ready to make your life more comfortable. These devices are generally called smart devices or embedded computers and are one of the five types of computers you can find today.

Supercomputers, mainframe computers, minicomputers, microcomputers and mobile computers are the main categories under which computers can be classified.

CLASSIFICATION OF COMPUTERS

Computers can be classified as general-purpose computers, specific purpose computers or super computers.

General-purpose computers compute a range of tasks but lack super speed and efficiency. The purpose of computers in this category might differ from one another: Examples are:

• desktop computers
• laptops
• tablets
• smartphones.

Specific purpose computers handle a specific problem or task. It uses a high level of accuracy and processing power. Examples are:

• servers
• embedded devices.

Super computers are extremely expensive, and the applications are for specialised activities or tasks such as weather forecasting.

Classification of computers in terms of data processing power and capacity could be done in the following grouping:

Take note

Examples of embedded computers are:

• ATM machines
• MP3 players
• DVD players
• Drones
• Anti-lock braking system
• Airbag control system
• Digital watches.

WHAT IS AN EMBEDDED COMPUTER?

Activity 1.3

1.3.1Identify the different types of computers illustrated below.

1.3.2Differentiate between the six types of computing devices.

1.3.3Which of the devices below are examples of embedded devices? Support your answers.

a.Mobile phone

b.Navigating system in a motor vehicle

c.A tablet

d.A robotic vacuum cleaner

d.Television decoder

1.3.4Your school wants to upgrade their computers in the media centre. A debate has started about whether to replace the desktop computers with laptops or tablets. Critique the options and give reasons for your choice.

UNIT

1.4

Advantages and disadvantages of using computers

In this unit, you will:

• list the advantages and disadvantages of using computers.

ADVANTAGES OF USING A COMPUTER

There are many advantages of using computers. However, the following are some of the most important ones to know:

1.Provides access to more information

2.Completes tasks that might be impossible for humans to complete

3.Saves time

4.Automates repetitive tasks

5.Allows for greater productivity

6.Allows for better communication and connections

7.Entertainment

DISADVANTAGES OF USING A COMPUTER

Unfortunately computers also have some disadvantages. These disadvantages include:

1.Social risks: computers provide humans access to social media, which can be addictive, make people less happy, lead to jealousy, and get in the way of real-world friendships. In fact, a study found that of 1 500 Facebook users interviewed, 62% said Facebook occasionally made them feel like they are not good enough, and 60% said that comparing themselves to other people on Facebook made them jealous.

2.Health risks: research has shown that excessive computer use can result in several medical problems, including back pain, eyestrain, obesity, carpal tunnel syndrome (CTS) and repetitive strain injury (RSI). However, with good ergonomic practices, many of these health risks could be reduced or removed.

New words

RSI (REPETITIVE STRAIN INJURY) – a painful inflammation of the tendons that often results from overuse. A tendon is tissue that attaches muscle to the bone

ergonomics – the study of how humans interact with fabricated objects, the goal is to create an environment that is well suited to the users’ physical needs

3.Security risks: computer security risk can be created by malware, that is, bad software, that can attack your computer system, destroy your files, steal your data, or allow an attacker to gain access to your system without your knowledge. Computers are programmed to follow instructions, and sometimes people program computers to act in a way that harms a user.

4.High cost: computers are expensive. Even the most affordable computers are still very expensive for the average person in South Africa. Since computers empower people, the high cost of computers puts pressure on people who are not able to afford them, and places them at a disadvantage.

5.Distractions/disruptions: if you have ever spent hours browsing the internet or watching videos on YouTube, then you know how distracting computers can be! Because of their high entertainment value, it is easy for computers to distract people and stop them from being productive.

6.Environmental impact: computers use a lot of electricity and in most cases the generation of electricity is harmful to the environment because of the carbon emissions. This has a huge impact on our planet.

Activity 1.4

1.4.1List any TWO advantages of computers.

1.4.2.List any TWO disadvantages of computers.

1.4.3.What do you use a desktop computer for?

1.4.4.In two teams, debate for and against the use of computers. Support your answers.

UNIT

1.5

Data and information management

In this unit, you will:

• explain and differentiate between data and information
• provide an overview of uses and examples of information within an organisation
• explain why information is useful
• provide an overview of a general model of an ICT system.

So far, we have spoken a lot about computers receiving data, manipulating the data, and then turning data into useful information. But what exactly is data and how does it differ from information?

Data can be defined as unprocessed numbers, or facts. Without first processing or changing data, it is meaningless. For example, your school might have data on the names, surnames, addresses, contact details, as well as the results of every class test, assignment, test, and exam of all current and past learners stored on a computer somewhere. While this data is important to store, it could be hundreds or even thousands of pages long and very difficult to interpret!

Information can be defined as facts and numbers that have been organised / processed so that it is useful / meaningful to people. For example, if your mathematics teacher wanted to see how well your current class is performing compared to last year’s class, she might ask your school’s database administrator to process the available data into averages for the two years. In that way, all those thousands of pages of data are processed into two numbers that can be compared easily. Similarly, the report you receive at the end of each school year takes all the data that teachers have collected during the year and turns that data into a single report that you can use to measure your performance.

Figure 1.8:

Data is unprocessed facts while information is organised

One of the main functions of a computer is to take unprocessed data (data that is useless to humans) and then turn it into something that is meaningful and easy to understand for humans.

OVERVIEW OF AN ICT SYSTEM IN ORGANISATIONS

Information is useful in an organisation because it will speed up the decision-making process, and help the business to improve their business service offering.

For example, supermarkets and chain stores use ICT systems for a variety of reasons. Let’s look at an example of a Point of sale (POS) system, paying special attention to the processes of receiving, storing, conveying, and manipulating data.

EXAMPLE OF A POINT OF SALE SYSTEM PROCESS:

From the cashier and customer’s perspective, a supermarket’s ICT system is a standalone computer, called a cash register. However, it consists of much more than that.

Most products have a barcode, which is a pattern of narrow and wide stripes that is read by a barcode reader. The barcode consists of information about the product such as, availability in store, quantities, orders, etc. The scan reader will scan the barcode optically and convert the stripes into numerical data, which is then transferred automatically to the checkout computer (cash register). The barcode reader sometimes beeps after scanning an item to signal to the cashier that the item is now identified.

Look at the IPO table below to see how this process works:

Figure 1.9:

An example of a POS sale system process

Activity 1.5

Answer the questions, which are based on the three scenarios below.

Scenario 1

Increasingly, the internet and big data are combined with mobility and social networking to allow companies to respond speedily to customer demands. Let’s use the Red Robin restaurant chain in the United States as an example.

A while ago, they tested a new hamburger across the chain and gave their frontline waiters devices on which to input customer feedback – likes and dislikes – about the burger. Normally the testing, feedback and response loop would have taken 12 to 18 months. This time round they were able to get a new, improved burger on to the menu within four weeks.

Scenario 2

In South Africa, the Johannesburg Road Agency’s (JRA) Find and Fix app allows motorists to report issues such as potholes and broken traffic lights as they encounter them, with one or two clicks on a smartphone.

Scenario 3

The internet of things (IOT) is about four big trends: social, mobile, cloud and big data; by using data and information collected through things like mobility and sensors and the cloud to make smarter, better decisions or to provide better, quicker service. It helps to collect and analyse data faster, understand customers, make decisions faster, and provide better service to customers.

[Adapted from The Mail and Guardian, 4 June 2014 (http://mg.co.za/article/2014-06-04-inside-the-internet-of-things)]

1.5.1Explain the term ‘data’.

1.5.2List the examples of data in each scenario.

1.5.3List the examples of information in each scenario.

1.5.4What device do you think the Red Robin restaurant gave their waiters to capture customer feedback?

1.5.5Draw an input processing output diagram for each of the scenarios.

1.5.6Explain the advantages of having information for each of the scenarios above.

CONSOLIDATION ACTIVITY Chapter 1: Basic concepts of computing

1.Which ONE of the following options gives the CORRECT order of the information processing cycle?

a.Input, processing, output, storage

b.Input, output, processing, storage

c.Input, processing, storage, output

d.Input, storage, output, processing

2.Which one of the following best describes this definition: This is a combination of computer-based technologies (such as computers and smartphones) with communication technologies (such as telephones, cell phones and the internet).

a.ICT

b.Network

c.Internet

d.None of the above

3.Which one of the following is NOT an output device?

a.Printer

b.Keyboard

c.Speakers

d.Monitor

4.Which ONE of the following is short-term memory?

a.Flash drive

b.ROM

c.Hard drive

d.RAM

5.Which type of software is built for a specific purpose, like playing a game?

a.System software

b.Application software

c.Utilities

d.None of the above

6.Choose the answer and write TRUE or FALSE next to the question number. Correct the statement if it is FALSE. Change the word(s) in bold to make the statement TRUE where necessary. (You may not simply use the word ‘NOT’ to change the statement.)

a.A communication device is a device that allows a computer to connect to a network.

b.Hardware refers to the set of instructions a computer uses to complete any task.

c.Smartphones and tablets have less processing power than notebooks. They also do not have a dedicated keyboard.

d.Information is defined as raw, unorganised numbers, signals, or facts.

e.Supercomputers are devices designed for a single purpose.

7.Fill in the missing information at a, b, c, d and e.

8.Look at the following input-process-output table.

The processes have been jumbled up. Copy the table and place them in the correct order.

Figure 1.10:

An example of a cell phone process

9.How do input and output devices differ from each other in terms of their function in a computing device?

10.Give TWO examples of a communication device.

11.What is the most popular input device on a smartphone?

12.What is the difference between data and information?

13.Briefly explain why software and hardware are interdependent.

14.Explain THREE disadvantages that computers have.

15.Explain what the function of a computer is in relation to data and information.

16.Your father has decided to buy the following computing device for his personal use. Use the specifications given to answer the following questions.

a.What category of computing device did he purchase?

b.What type of CPU is specified?

c.Give a disadvantage of this computing device.

17.Explain how an embedded computer differs from a general purpose computer. Give examples in your answer.

18.Complete the crossword puzzle below: