General Concepts (Grade 12 NSC Matric Computer Application Technology): Revision Notes

Computers and Their Uses

Introduction

Throughout history, many inventions have fundamentally changed how we live our lives, and the computer stands out as one of the most transformative. Computers have revolutionised our world by enabling us to make incredible technological and scientific breakthroughs, from exploring the deepest parts of our oceans to venturing into outer space. Most importantly, they help us stay connected with people across the globe, making our world feel smaller and more accessible.

One thing is certain: without computers, our lives would be dramatically different!

Types of computers

Let's briefly recap these important types:

Servers are powerful computers designed to serve multiple users simultaneously. They have robust processors, large hard drives, and substantial memory capacity. In network environments, servers store vast amounts of data that other computers can access and share. They also enable resource sharing, such as printers, across the network.

Workstations are high-performance computers designed for individual professional use. They're faster and more capable than regular personal computers, making them ideal for businesses and specialised applications used by engineers, architects, and graphic designers.

Personal computers (PCs or Desktops) were once called "microcomputers" because they were compact compared to the massive business systems of their time. These are the most common and affordable type of computer, physically smaller with relatively modest memory and processing power. They're designed for individual use and aren't built to be portable since they consist of separate components.

Laptops and Notebooks combine all computer components - display, keyboard, processor, memory, hard drive, and trackpad - into one portable package. They run on battery power, making them completely portable and convenient for users who need computing power on the go.

Tablets are even more portable than laptops, being smaller and lighter. While generally less expensive than brand new laptops, their processors and components are typically less powerful than traditional laptops, making them ideal for basic computing tasks and media consumption.

Smartphones are handheld computers that use flash memory instead of traditional hard drives for storage. They feature virtual keyboards and touch-screen technology, combining computing power with excellent portability and battery life.

Embedded systems are specialised computer systems built into other devices to perform specific tasks. You'll find them in everyday items like automatic teller machines (ATMs), MP3 players, and many other electronic devices.

What is a computer and how does it work?

Whether you're holding a smartphone or working with a powerful server, all computers operate using the same five fundamental principles. These core functions work together seamlessly: input, processing, storage, output, and communication. Each component plays a vital role, but they all collaborate to make the computer function effectively.

The information processing cycle illustrates how computers transform raw data into useful information through these five interconnected stages. Understanding this cycle is crucial for comprehending how any computing device operates.

Input

The input stage is where data enters the computer system. There are numerous ways to input information, corresponding to the variety of input devices available. You're already familiar with input devices from Grade 10, such as keyboards, touchscreens, and microphones.

When you input data - whether by typing on a keyboard or speaking into a microphone - the computer receives this information and converts it into binary code (a series of 1s and 0s). This conversion is essential because computers can only understand and process information in this binary format.

Processing

The Central Processing Unit (CPU) serves as the computer's brain, taking the binary code from the input stage and performing the necessary calculations to transform it into meaningful information. The CPU collaborates with the computer's memory to receive instructions on how to display and manipulate the input data.

This processing involves storing information as pixels in the computer's memory, which can then be sent to output devices for display in a user-friendly format. Remarkably, this entire process happens in a fraction of a second, demonstrating the incredible speed of modern computers.

Storage

Storage is where the computer saves input data in its memory banks. This process follows several steps:

1. Initially, the CPU writes data to the computer's temporary storage, known as Random Access Memory (RAM)
2. The computer then waits for the user's instruction to transfer data from RAM to more permanent storage
3. When commanded, the computer saves the data to the disc drive in either a default location or a user-specified location
4. Users can retrieve this stored information at any time

Output

During the output stage, the computer takes the processed pixels and displays them in a format that users can understand and interpret. Various output devices accomplish this task, including printers, screens, video displays, and audio devices.

These output devices transform raw computer data into usable, visible information that humans can understand. This transformation might result in sound waves from a song, text in a document, or images on a screen - essentially converting digital information back into formats we can perceive and use.

Communication

Communication enables computers to share information with users and connect with other computer systems. This stage facilitates the exchange of data across networks, enabling the global connectivity that defines modern computing.

Why do we use computers?

Computers have become integral to our daily lives because they excel in several key areas that significantly improve our productivity and quality of life:

• Enhancing productivity across various tasks and industries
• Assisting scientists in finding cures for diseases through data analysis and modelling
• Helping architects design and construct complex new buildings with precision
• Empowering people in developing countries by providing access to global opportunities and education

Let's explore some specific reasons why computers have become so essential in our modern world.

Saving time

One of the most significant advantages of modern computers is their ability to save enormous amounts of time and effort. From finding the quickest route to the mall using Google Maps to sending urgent emails to work colleagues, computers complete tasks much faster and with greater ease than traditional methods.

Communication costs

Computers have dramatically reduced the cost of communicating with people worldwide. Video conferencing is significantly cheaper than purchasing plane tickets for face-to-face meetings, and sharing files over the internet is more economical than traditional mailing methods.

Efficiency

Computers enable us to obtain, store, and retrieve data both quickly and efficiently. For instance, you can research any topic on the internet in less than an hour, a task that previously might have taken days in a library. Many repetitive human tasks can be time-consuming and prone to errors, but computer technology reduces completion time while minimising or eliminating mistakes.

Saving labour

The automotive industry provides an excellent example of how computers and automation reduce labour requirements. While a person might take two months to two years to assemble a car by hand, computer-controlled automation can produce a fully assembled and painted vehicle in approximately 8 hours.

This dramatic reduction in production time demonstrates how computer technology and robotics have revolutionised manufacturing processes across numerous industries.

Accuracy and reliability

Humans are emotional beings who can be affected by various internal and external factors. We experience tiredness, make mistakes, and sometimes struggle with tasks we don't enjoy. In contrast, computers are programmed to perform specific tasks in precise ways for set durations, executing them accurately, efficiently, and reliably every time.

Effect on time and distance

The efficiency, accuracy, and reliability of computers have transformed how we communicate with each other, enabling us to:

• Have conversations with friends and family in other countries using Voice over Internet Protocol (VoIP)
• Conduct business meetings with colleagues in different cities using platforms like Skype
• Send instant messages to people across the world via email
• Access online banking services to pay bills, view account balances, transfer funds, and much more

Financial institutions have enhanced consumer security by adding features like the ability to freeze missing credit cards to prevent fraudulent charges. These technological controls will only expand as biometric and facial recognition technologies advance.

Environmental benefits - saving paper

Computers enable users to compile data using spreadsheets, write letters using word processors, send messages via email, and complete forms through online applications. Each of these computer-based conveniences reduces the time and effort required for these activities while importantly reducing paper consumption.

Global communication, including social networks and web tools

One of the most appreciated features of computers is their ability to connect and form networks. These networks can link computers in homes or offices, enabling users to share files. Networks can span great distances, with the internet being the largest network, consisting of hundreds of thousands of computers worldwide.

Computer networks have enabled users to discover new and exciting ways to upload and share information, including:

Social networks are specialised computer networks that facilitate social interactions between users by enabling them to share personal information, including likes, dislikes, videos, and photos. Popular social networks include Facebook, Twitter, Snapchat, and Instagram.

Web tools encompass various online platforms:

• Blogs function as online diaries where users share daily experiences with others. Examples include "Boing Boing" and "PlayStation Blog"
• Wikis are collaborative websites allowing users to share information on virtually any topic, from television show plots to photosynthesis processes. Wikipedia represents the most famous wiki, though many other topic-specific wiki websites exist
• Vlogs (video blogs) are blogs where content is primarily presented in video format rather than text