Computer Science for Secondary Schools
Student's Book - Form One
Ministry of Education, Science and Technology - Tanzania
Chapter One: Introduction to Computer Science
Introduction
The world is undergoing great changes in science and technology, and the use of computers has taken a large part of human life. For example, Artificial Intelligence (AI), is used in many areas of our daily lives to increase productivity and efficiency. AI is one of the fastest-developing fields in Computer Science, which is transforming the world. In this chapter, you will learn about Computer Science, its branches, relevance, applications, and fields related to Computer Science. The competencies developed will enable you to recognise the significance and application of Computer Science in everyday life.
Concept of Computer Science
Read scenario 1.1 and then answer the questions that follow.
Surprising things are happening today. Doors are automatically opened. The doors sense the presence of a person and get opened. A similar situation may be observed in tap water, where you don't need to touch the tap; it just senses your hand and pours up water. Technology is advancing very fast to the point that we have airplanes, trains and vehicles that do not need human drivers.
Questions
- What kind of technology do you think is behind these autonomous actions?
- Have you ever come across any autonomous system? Describe it.
Meaning of Computer Science
The field of Computer Science is helping us make things better and faster. We are moving from doing things manually to doing things automatically. Behind all these automations is the use of advanced computer systems. Those computer systems are developed using principles of Computer Science.
Computer Science is the study of how computers work. It is about learning the rules and how things are done in the computer world. It involves learning how to build a computer set instead of just using it. Generally, Computer Science is about building and understanding the computer.
Imagine that you want to cook a cake. You need to follow a recipe, which is a set of instructions that tell you what ingredient to use and what steps to take. The computer also follows a logical set of instructions known as an algorithm to solve a problem. A computer algorithm is similar to a recipe. It is a set of instructions that tells a computer what steps to take to solve a problem or perform a task.
In the world of computers, algorithms are used to solve problems and make things happen. For example, let us say you are playing a game of card on a computer. The computer needs to know how to move the card to win the game. That is where algorithms come in. They tell the computer how to move the pieces to win. So, Computer Science is concerned with learning how to build and understand these algorithms.
Activity 1.1
Use the library or reliable online sources to read articles, books, and other publications on the history, concepts, and developments in Computer Science. Gain insights into the foundational principles and explore how Computer Science has evolved over time. Document the findings in a portfolio.
Questions
- In your exploration, what factors influenced the development of Computer Science?
- Does this influence affect your everyday life? Explain briefly.
Branches of Computer Science
Computer Science is divided into many branches. Each branch focuses on different aspects of computers such as how to build and program a computer. Another aspect might be about how to make a computer understand human language. A few branches of Computer Science are:
- Artificial Intelligence (AI): This branch of Computer Science deals with making machines intelligent so that they can think and solve problems like humans.
- Data Science: This branch involves obtaining insights and knowledge from large datasets through statistical analysis and machine learning techniques.
- Software Engineering: This branch focuses on how to design, develop, test, and maintain software systems.
- Computer Networking: This part of Computer Science is about ensuring computers can communicate with each other and share information.
- Cyber Security: Focuses on protecting computer systems and networks from security breaches, damages, attacks, and unauthorised access.
- Computer Architecture: This branch of Computer Science deals with designing and organising the parts of a computer to make it work.
- Quantum Computing: This branch of Computer Science focuses on using the rules of quantum theory to make computers work better and faster.
Activity 1.2
Use the library or reliable online sources to explore other branches of Computer Science apart from those mentioned in this chapter. Write the summary and document the findings in a portfolio.
Questions
- Did you find other branches? If yes, what differentiates them from the one you learnt in this section?
- Which branch do you think is more relevant to you and should be your primary focus in your career? Why?
Importance of Computer Science
Computer Science plays an essential role in the modern world. The importance of Computer Science is as follows:
- It helps to create all the software we use on our computers and devices.
- It contributes to technological innovation, which improves and speeds up processes that allow constant change.
- It helps to make everything work better and faster, from learning in school to buying things in a store.
- It helps us in develop systems that connect and share information across different devices and platforms. For example, you can message to your friend on your phone or computer.
- It helps us use lots of information to make decisions and make things better.
- It helps in designing systems that keep our information safe and private. So, we can use the internet and our devices without worrying about bad people trying to get our information.
- It helps us make robots that can do things on their own, like driving cars or picking up things in a factory.
- It helps in creating entertainment, such as video games, movies, and music.
- It helps us solve big problems in science and engineering. For example, figuring out how to grow food, predicting the weather, finding new medicine, and making things lighter and more durable.
Chapter Summary
Computer Science holds significant importance in the modern world due to its significant impact on society, economy, and technology. It has driven technological advancements, enabled digital transformation across industries, and opened vast job opportunities. The field fosters innovation and research, equips individuals with problem-solving skills, and plays a vital role in education and other sectors. Moreover, it has revolutionised communications and connectivity, strengthened cyber security, and enhanced entertainment and creativity. Embracing Computer Science is essential for progress, innovation, and thriving in the digitally driven era.
Revision exercise 1
- Explain the role of Computer Science in developing practical solutions to enhance transportation systems.
- Explain the significance of Computer Science various in industries.
- There has been a revolution in entertainment due to advances in Computer Science. With examples, explain how Computer Science plays a role in this revolution.
- Discuss how Computer Science improves teaching and learning and give examples of software or platforms that support education delivery.
Chapter Two: Computer Systems
Introduction
The computer is one of the most revolutionary and powerful tools ever developed in the history of the modern world. It plays significant roles in different aspects of our daily lives. In this chapter, you will be introduced to the concept of computer systems, computer generations, and the significance of computers in performing different tasks. The competencies developed will enable you to articulate the potential of computer systems and their use.
Concept of Computer Systems
Read scenario 2.1 then answer the questions that follow.
The world is proceeding to paperless and cashless transactions. For example, Kole, who is the general manager of BENICO company always requests and makes all payments online. Kole checks his company's bank balance using a mobile phone. She enters her delivery address and payment details. The computer systems take steps to ensure the safety of the transaction by encrypting sensitive data during transmission and protecting BENICO's company information.
Questions
- How does the payment system recognise Kole?
- What is the role of encryption during transactions?
- What information must be encrypted?
Meaning of Computer Systems
Modern life is determined by the ability to process large amounts of data quickly and accurately. Nowadays, computers perform complex tasks, solve problems, and connect with the world. Such abilities were not easy a few decades ago. These abilities are enabled by advancements in the field of Computer Science and related technology. A computer is an electronic device that processes data and transforms it into information that is useful to people. A computer, regardless of its size, type, or purpose, is controlled by a set of instructions that tell the machine what to do. Therefore, a computer system is a complex arrangement of hardware, software, user, and data that work together to perform various tasks and processes.
Components of Computer Systems
The fundamental components of computer systems include hardware, software, and users. Understanding the components of computer systems is essential for realising how computer systems function.
Hardware
These are physical components of a computer system that can be seen and touched. They are used for performing various tasks, including entering and displaying data and processing the data. Examples include mouse, keyboard, RAM, and monitor. More details of computer hardware will be covered in Chapter Three.
Computer case or system unit
A computer system unit, sometimes called a system unit or computer case, is the enclosure that houses the main internal components of a computer. Its primary role is to protect and arrange these internal components and connect them to external components which are usually known as peripherals.
Software
These are instructions that govern the operation of a computer system. Software tells the computer what to do. Some software are designed to control the computer itself, for example by managing its resources. Other software are meant for the end user to perform their day-to-day activities, such as creating documents, searching for information, or editing music. The details of computer software will be covered in Chapter Four.
Data
These are the raw facts entered in to a computer system that is used to make decisions, solve problems, or gain insights. For example, the name of a student, subjects, and corresponding marks is a single point of data. It might not have any meaning by itself. However, when computed into total and average, that data gives information such as the student's progress. That information can be used to make some conclusions or develop insights about the student.
Users
Refer to individuals who interact with and utilise the computer and its resources to perform various tasks and achieve specific objectives.
Exercise 2.1
- What if computers did not exist in today's world?
- Baraka is a student at Kantalamba Secondary School. While in the school's computer laboratory, he enjoys playing games on his computer. Neema is the technician in charge of the computer lab. Describe their roles in terms of computer systems.
Computer Generations
Computer generation refers to the ongoing evolution and development of computers and computing technology over several generations. Each generation represents a significant leap in terms of hardware, software, and overall computing abilities. These advancements have shaped the way we live, work, and interact with technology.
The different computer generations are:
First Generation (1940s-1950s)
- These are computers that were developed between the 1940s – 1950s.
- They were characterised by vacuum tubes as the primary electronic components.
- Computers were large, expensive, and consumed a lot of power.
- Examples include the ENIAC and UNIVAC computers.
- They had limited computational capabilities and were used primarily for scientific and military applications.
- They were using machine-level language programming.
Second Generation (1950s-1960s)
- They were developed between 1950s -1960s.
- They used transistors instead of vacuum tubes.
- They had smaller sizes compared to the first-generation computers.
- They had less power consumption.
- Magnetic core memory was introduced, improving data storage.
- They used assembly languages, and high-level programming languages like Fortran and COBOL emerged.
- They had batch processing capability and the concept of operating systems began to develop.
Third Generation (1960s-1970s)
- They were developed between 1960s-1970s.
- They used Integrated Circuits (ICs).
- They became smaller in size compared to the second generation.
- Introduction of the IBM System/360 series and early mainframes.
- They had increased processing power.
- They used high-level programming languages like BASIC and Pascal.
- Multiprogramming and time-sharing operating systems allowed multiple users to interact with a single computer simultaneously.
Fourth Generation (1970s-1980s)
- They were developed between 1970s-1980s.
- They used Very Large-Scale Integration (VLSI) technology that enabled the creation of microprocessors.
- Personal computers (PCs) like the IBM PC and Apple II were introduced.
- They had Graphical User Interfaces (GUIs), and the mouse was invented.
- High-level languages such as C, C++, and Java gained popularity.
- Networking and the internet began to take shape.
Fifth Generation (1980s-Present)
- They were developed between 1980s-Present:
- They continued to deploy advancements in microprocessor design, storage, and networking.
- PCs became more affordable and widespread.
- There was the rise of mobile computing, with laptops, smartphones, and tablets.
- The World Wide Web (WWW) revolutionised information access and communication.
- Artificial Intelligence (AI) and machine learning gained prominence.
- Cloud computing and virtualisation changed how data and software are stored and managed.
Future Generations
- Quantum computing holds the promise of exponential processing power.
- Neuromorphic computing mimics human brain architecture for AI applications.
- Continued advancements in nanotechnology may lead to even smaller and more powerful computing devices.
- Increased emphasis on sustainability and energy efficiency in computing.
Chapter Summary
A computer system is a complex interconnected network of hardware and software components designed to process and store information. A complete computer system includes hardware and software. Hardware consists of electronic devices, the parts you can touch. Software, also known as programs, consists of organised sets of instructions for controlling the computer, the parts you cannot touch.
Supercomputers are the most powerful computers in terms of processing. Mainframe computers handle massive amounts of input, output, and storage for multiple users. Minicomputers are smaller than mainframes but larger than personal computers. They often support multiple users. Workstations are powerful single-user computers that are used by engineers, scientists, and graphic artists. Desktop computers are the most common type of personal computer. Notebook computers and laptops are used by people who need portable computing power outside the office or away from home. Handheld personal computers are the smallest computing devices. They lack the power of a desktop or notebook PC, but they offer specialised features for users who need only limited functions and small sizes.
Revision exercise 2
A: Multiple choice
- Which of the following best describes the first-generation computers?
- Featured graphical user interfaces.
- Used vacuum tubes for processing.
- Utilised integrated circuits.
- Used transistor technology.
- Which computer generation introduced the concept of personal computers (PCs) and graphical user interfaces (GUIs)?
- Second Generation
- Third Generation
- Fourth Generation
- Fifth Generation
B: Matching items
Match the following computer generations with its associated technology:
| Computer generation | Technology |
|---|---|
| (a) Second generation computers | (i) Very Large-Scale Integration |
| (b) Fifth generation computers | (ii) Vacuum tube technology |
| (c) Fourth generation computers | (iii) Transistor technology |
| (d) First generation computers | (iv) Microprocessor design technology |
| (e) Third generation computers | (v) Integrated circuits technology |
C: Short answer
- Why the first-generation computers were large, over-heating, and power inefficient?
- Write a brief reflection on the relevance and significance of classifying computers and discuss how understanding these classifications can be helpful in various technology-related decisions.
- Imagine a school with a tight budget planning to buy computers for its computer laboratory. As an advisor, recommend suitable computers they should buy and give reasons to explain your selection.
- Create a timeline that shows how computers evolved over different generations. Use at least four generations and mark important advancements or key points for each one.
- Explain why the development of microprocessors was a major development in computer technology.
- Assess the importance of transitioning from vacuum tubes to transistors in computer development. Give two reasons why transistors were deemed superior to vacuum tubes.
Chapter Three: Computer Hardware
Introduction
In today's world, computers are essential, and a lot of people use them daily. These computers operate relying on the interaction of various hardware components working together. Possessing a basic understanding of computers is essential for navigating the modern world and avoiding being left behind. In this chapter, you will learn the concept of computer hardware, input, storage, processing, and output devices. The competencies developed will enable you to use computer hardware for different purposes.
Concept of Computer Hardware
Meaning of Computer Hardware
Computer hardware is the collection of all the tangible parts of a computer that can be seen and touched. They work together to enable the functioning of a computer. These parts are classified into input, processing, storage, and output devices. Input devices include mice and keyboards. Processing devices refer to the central processing unit (CPU). Output devices include the monitors and printers. Storage devices include hard disk drives and DVDs.
Types of Computer Hardware
Computer hardware is categorised based on its operations, namely input, processing, storage, and output. Hardware components are usually called devices, hence the terms input, processing, storage, and output devices.
Input Devices
These are devices that control signals that initiate the process of a computer system. These devices convert the input data into a digital form that is understandable to the computer. These devices are used to enter raw data (input) into the computer to be processed into information. Some examples of input devices include keyboards, mice, scanners, joysticks, digital cameras, microphones, light pens, and touch screens.
Keyboards
A computer keyboard is an input device used to enter data into the computer system by pressing buttons or keys. It contains keys for individual letters, numbers, and special characters, as well as keys for specific functions and punctuation marks. The keyboard is connected to the computer system using either a cable or a wireless connection. Laptops have in-built keyboards, while other mobile devices like tablets and smartphones use virtual keyboards.
The keys for the keyboard are grouped as follows:
Alphanumeric keys
This part of the keyboard is for typing letters on the computer. The letters are arranged in three rows but not in the ascending order of the English letters. In some computers, the first row consists of the letters Q, W, E, R, T, and Y, such a keyboard is known as a QWERTY (pronounced as KWER-tree). Usually, the spacebar is included in alphanumeric keys.
Modifiers keys
These are keys that modify the input of other keys. Modifier keys include the Shift key, Control (Ctrl) keys, and the Alternate (Alt) key.
- The Shift key: This is the modifier key on the keyboard that performs different functions. For example, pressing and holding the shift key while pressing a letter a key would generate a corresponding capital letter. The shift key is commonly located on both the left and right-hand sides of the keyboard for typing efficiency.
- Control (Ctrl) keys: These keys are found on standard computer keyboards on the bottom left and right of the keyboard. It is mostly used in combination with other keys to perform some functions or commands. For example, Ctrl + Alt + Del on a Windows computer opens the task manager application that gives an option to terminate a process, active programs, or reboot the computer.
- The alternate (Alt) key: Like the Shift keys, the Alt keys are modifier keys that are used to change (alternate) the function of other pressed keys. For example, the key combination Alt + Tab, that is, pressing and holding the Alt key and then pressing the Tab key, enables to switch between open windows.
Function keys
The keys, F1 through F12, are called function keys. They may have various uses, depending on the installed operating system. A computer program that is currently opened may also change how each of these keys operates. A piece of software may use function keys independently or combine function keys with other keys, such as the Alt or Ctrl keys. For example, when you press Alt + F4 in Microsoft Windows, the active window closes.
Chapter Summary
Computer hardware is an important component of modern computing systems. Computer hardware refers to the physical components of a computer system. It includes the tangible parts that you can see and touch. Hardware is subdivided into input, output, processing, storage, and devices. Input devices, such as mice and keyboards, are used to send data to the computer for processing. Output devices are used to present the processing results to the user. To work properly, input devices need special software to be installed on the computer. This software is known as a device driver.
Processing is done by the central processing unit (CPU), which consists of two main parts, namely, the control unit (CU) and the arithmetic logic unit (ALU). The CU controls the overall functioning of the computer, including memory access and instruction fetching and decoding.
The ALU is responsible for performing arithmetic and logic operations. Computer memory consists of primary and secondary memory. Forms of primary memory include random access memory (RAM), registers, and cache memory. Secondary memory is characterised by higher capacity, slower access speed, and non-volatility. Secondary storage comes in many forms, including magnetic discs, flash discs, and optical discs. Primary memory has a relatively low capacity but higher access speed than secondary memory.
Registers and cache memory are located inside the CPU. Common units for denoting the storage capacity of computer memory are megabytes (MB), gigabytes (GB), and terabyte (TB). The role of input devices is to input data into the computer, while the output devices are used to present processed data to the user.
Revision exercise 3
- Explain the differences between primary and secondary storage devices.
- What is the importance of an output device?
- What is the role of speakers as output devices in a computer system compared to printers?
- What are some common uses of a joystick in computer systems?
- What are some advantages and disadvantages of using a touch screen as an input device?
Chapter Four: Computer Software
Introduction
The intermediary connecting users and hardware is called software. The software enables computers to perform diverse tasks and plays a central role in our daily lives. The development and evolution of software continue to shape technology and society. In this chapter, you will learn the concept of computer software. The competencies developed will enable you to deepen your understanding of computers.
Chapter Summary
Computer software refers to the programs that enable a computer to be specific tasks. Software can be categorised into two types: system so and application software. System software includes operating systems of Windows, MacOS, Unix, and Linux, which manage the computer's response and allow communication between hardware and software components. System software also includes device drivers which enable hardware computers to work with the operating system, and utility software, which is used to provide specialised tasks.
On the other hand, application software, on the other hand, consists of processes designed for specific tasks, such as word processors, web browsers, players, graphics editors, and more. Software developers create and make these applications to cater for the diverse needs of users.
Chapter Five: Computer System Handling and Care
Introduction
Handling and caring for computer systems is essential for ensuring the proper use and protection of computers in reference to practices and precautions taken. In this chapter, you will learn the concepts of computer handling and care, hardware care, software care, and safe handling practices. The competencies developed will enable you to use computers safely.
Chapter Summary
Computer handling is caring for the computer system and its accessories so that they perform their work properly. Computer system handling involves a wide range of tasks and responsibilities. They include hardware and software management, proactive maintenance, security measures, data protection, and disaster preparedness. The goal is to ensure that the computer system operates optimally and meets the requirements of its users. By proactively addressing these aspects, organisations and individuals can ensure that their computer systems operate reliably, securely, and efficiently. Computer care measures include power management, using utility software for optimising performance, and securing computers from viruses and other malware.
Chapter Six: Computer System Maintenance
Introduction
During the process of using computer systems, various problems may occur and lead to poor performance and operational costs. Regular maintenance of a computer system is a vital practice that helps to avoid these problems and ensure reliable performance and cost-effectiveness. In this chapter, you will learn the concept of computer system maintenance, and how to perform preventive, corrective, and routine maintenance of computer systems. The competencies developed will enable you to demonstrate the ability to manage computer systems effectively.
Chapter Summary
Computer system maintenance refers to a set of activities and practices to ensure smooth functioning, reliability, security, and best performance. Proper maintenance helps extend the life of the system, reduces downtime, and minimises the risk of data loss or hardware failure, computer maintenance includes software installation and managing disks. The specific installation and managing steps may vary based on the Operating System you are using (Windows, macOS, or Linux). The general guide on how to manage disks before software installation involves data backup, checking disk space, disk partitioning, disk formatting, boot order, and reboot.
Computer system maintenance are preventive maintenance, corrective maintenance, and routine maintenance. Corrective maintenance, also known as "breakdown maintenance" or "run-to-failure" maintenance is a strategy where maintenance activities are performed after a problem or failure has occurred. In this approach, the equipment or system is used until it breaks down, and then repairs or replacements are carried out to restore it to working condition.
Routine maintenance is the process of identifying, analysing, and resolving problems or issues that occur in a system, device, software, or equipment. It involves a systematic approach to diagnosing and fixing problems to restore the system's functionality and ensure it operates as intended.
Chapter Seven: Computer System Troubleshooting
Introduction
Sometimes computers can have problems that prevent them from working properly. Fixing these problems is important to make sure computers work as expected. In this chapter, you will learn about computer system troubleshooting. The competencies developed will enable you to effectively manage technical issues, increase efficiency and reduce expenses, retrieve lost data, improve security, and help others.
Chapter Summary
Troubleshooting is the process of identifying, analysing, and resolving problems or issues that occur in a system, device, software, or equipment. The goal is to fix the identified problems and restore the system's functionality to ensure it operates as intended. Troubleshooting involves investigating various components, configurations, settings, and interactions within the system.
There are four areas to consider when doing computer troubleshooting. These areas are hardware, software, performance, and electrical troubleshooting.
Common hardware problems include booting failure, application slowness, stuck applications and frozen computers. Software troubleshooting involves systematic diagnosis of the problem. It extends to gathering information and implementing solutions to restore the software to its intended functionality.
Performance troubleshooting involves diagnosing problems that may be causing a computer to run slowly or experience other problems. Electrical troubleshooting involves diagnosing problems that may be causing electrical malfunctions, such as power outages, electrical shocks, equipment failures, or circuit overloads.
Chapter Eight: Problem Solving
Introduction
In daily life, there are always problems that need to be solved. These problems may be simple or complex. For example, we often need to solve simple problems, such as a mathematical equation, or solve a more complex problem, such as analysing data and writing a report. These problems can be solved by hand using pen and paper or computer. Solving a problem by hand usually takes a lot of time and money. Solving a problem requires a systematic approach that involves understanding that problem, deciding on a strategy and laying down a set of steps to be followed to solve the problem (an algorithm). In this chapter, you will learn the concept of problem solving; and algorithm development and representation. The competencies developed will enable you to identify problems and develop algorithms for solving real-life problem.
Chapter Summary
Problem-solving is a cognitive process fundamental to human existence. It involves identifying challenges, developing algorithms, and implementing solutions. Effective problem-solving demands creativity, critical thinking, and determination. Importance of problem-solving skills are important in developing a solutions, as they help design a good algorithms, break the problems into a smaller subproblems and help in the effective implementation of a solutions.
Steps for problem solving using a computer include:
- identify the problem,
- understand the problem,
- identify alternative ways to solve the problem,
- select the best way to solve the problem from the list of alternative solutions,
- list instructions that enable you to solve the problem using the selected solution, and,
- evaluate the solution.
An algorithm is a precise set of instructions or steps designed to solve a specific problem. Algorithms serve as the backbone of computer programs and problem-solving processes. They enable a systematic and efficient solutions, impacting fields from technology to science, underpinning our digital world. Algorithms have a definite beginning, an end, and a finite number of steps. A good algorithm is finite, programming language independent unambiguous; receives input and produces an output. Algorithms are represented using flowcharts and pseudocodes. A flowchart is a diagrammatic representation of algorithm using various symbols connected by arrows.
An algorithm, where all the steps are executed one after the other is said to run in sequence. Decision-making involves selecting one of the alternatives based on the outcome of a condition.
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