Information and Communication Technology (0417) | Hardware and software

Welcome to the Core of ICT: Hardware and Software!

Hello! This chapter is the foundation of everything we study in ICT. Think of a computer system like a human body: it needs physical parts to exist and intelligence (instructions) to function.
By the end of these notes, you'll clearly understand the difference between the physical bits (hardware) and the instruction sets (software), and how they work together to process information. Let's dive in!

1.1 Defining Hardware and Software

The Two Halves of a Computer System

Every ICT system relies on two essential elements working together:

1. Hardware (The Physical Stuff)

Hardware consists of the physical components of a computer system. You can touch it, feel it, and sometimes accidentally drop it!

Analogy: If a computer were a car, the hardware would be the engine, wheels, and chassis.

Examples of hardware include:

• The keyboard and monitor (what you use).
• The CPU and RAM (internal brains).
• Hard drives and external storage devices.

2. Software (The Invisible Instructions)

Software refers to the programs (sets of instructions) that tell the hardware what to do. It controls the operation of the computer or processes electronic data.

Analogy: If a computer were a car, the software would be the instructions in the manual telling you how to drive it, or the computer chips controlling the engine.

1.2 The Main Components of Hardware

To perform its tasks, a computer needs four core types of hardware components. The syllabus focuses on both internal components (inside the machine) and external components (peripherals).

A. Internal Processing Components

Central Processing Unit (CPU) / Processor

The CPU is often called the "brain" of the computer.

• Role: The CPU's primary role is to execute instructions entered into the computer in order to process data and produce an output.
• It controls all the other parts of the system and performs all the calculations and logic operations.

The Motherboard is the main circuit board that connects the CPU, memory, and all other internal components, allowing them to communicate.

B. Internal Memory (Primary Storage)

Internal memory (or primary storage) is where the CPU holds data and instructions it is currently using. We focus on two types: RAM and ROM.

Random Access Memory (RAM)

RAM is the computer’s working space. It holds the operating system, current applications, and data currently being processed.

• Characteristic 1: Volatile. This is the most important characteristic! When the computer is switched off, all data in RAM is lost.
• Characteristic 2: Read/Write. The CPU can both read data from it and write new data to it.
• RAM is generally much faster than backing storage.

Analogy: Think of RAM as your physical desk. While you are working, all your current documents are spread out on the desk (RAM). When you finish and turn off the light, you clear the desk and everything disappears (Volatile).

Read-Only Memory (ROM)

ROM holds permanent, essential instructions needed to boot (start up) the computer system (like the BIOS).

• Characteristic 1: Non-Volatile. The data is not lost when the power is switched off.
• Characteristic 2: Read-Only. The data cannot usually be easily changed or erased by the user.

C. Other Key Hardware Components

These components handle specific tasks or allow connection to other devices:

• Graphics Card: Processes and outputs images to the monitor.
• Sound Card: Processes and outputs sound to speakers or headphones.
• Network Interface Card (NIC): Allows the computer to connect to a network (like the Internet or a LAN).
• Camera: An input device for capturing images or video.
• Input and Output devices: Devices that enable data entry (Input) or display/present results (Output). (Covered in detail in Chapter 2).

D. Backing Storage (Secondary Storage)

Backing storage (or secondary storage) is used for the long-term, permanent storage of data and programs.

• Characteristic: Always non-volatile (data is safe when power is off).
• Examples: Fixed or portable magnetic hard drives, Solid State Drives (SSD), CDs, DVDs, Blu-ray discs.

2.0 Understanding Software

Software is categorised based on its purpose: whether it helps the user directly or helps the computer manage itself.

2.1 Application Software

Application software (or "apps") provides services that the user requires to solve a specific task. These are the programs you use daily to create, communicate, or entertain yourself.

Examples of Application Software (You must know these examples):

• Word Processing: Creating and editing documents (e.g., writing an essay).
• Spreadsheet: Performing calculations and financial analysis (e.g., budgeting).
• Database Management Systems: Storing, organising, and retrieving data efficiently (e.g., student records).
• Control & Measurement: Programs used to monitor systems (e.g., climate control in a smart home).
• Graphics Editing, Video Editing, Audio Editing: Tools for manipulating multimedia.
• Computer Aided Design (CAD): Software used by engineers and architects to design objects.
• Applets and Apps: Small applications designed for specific tasks, often on mobile devices.

2.2 System Software

System software provides the services that the computer requires to operate efficiently. It manages the hardware and provides a platform for application software to run on.

Analogy: If Application Software is the map, System Software is the engine and steering wheel that make the car actually move.

Examples of System Software (You must know these examples):

• Operating Systems (OS): The most important system software (e.g., Windows, macOS, Android). It manages all hardware and software resources. (Covered in detail in Syllabus 1.3).
• Device Drivers: Small programs that allow the OS to communicate with specific hardware components (e.g., printer drivers).
• Utilities: Programs that perform maintenance tasks (e.g., anti-virus software, file compression tools).
• Compilers and Linkers: Tools used by programmers to translate code into machine-readable instructions.

3.0 Analogue and Digital Data

Computers work with data in a specific format, which means real-world signals sometimes need conversion.

What are the characteristics of Analogue and Digital Data?

Analogue Data

Analogue data is continuous, infinite, and changes smoothly over time.
Example: A wave representing sound, temperature reading from an old-fashioned thermometer, or the volume knob on an old radio.

• Characteristic: Represented by continuously varying physical quantities (like voltage).

Digital Data

Digital data is discrete, countable, and represented in steps, typically using the binary system (0s and 1s). This is the only way a computer can understand and process information.

• Characteristic: Represented by distinct, separate values (0 or 1, ON or OFF).

Analogy: A ramp is Analogue (continuous change in height). A staircase is Digital (specific, discrete steps).

The Need for Conversion

Since the real world is analogue but computers are digital, we often need converters:

1. Analogue to Digital Conversion (ADC)

Purpose: Analogue data must be converted to digital data so it can be processed by a computer.
Example: When you use a microphone (which captures analogue sound waves) on your PC, the sound card uses an ADC to turn the waves into binary data that the computer can record and store.

2. Digital to Analogue Conversion (DAC)

Purpose: Digital data must be converted back to analogue data so it can be used to control devices in the real world.
Example: When a computer controls a speaker, the DAC converts the stored binary audio file back into an analogue electrical signal that makes the speaker cone vibrate, producing sound. This is also essential for controlling devices like motors or actuators in control systems.