Computer as a system: objective, components and environment

The four questions, asked of a computer

Your book calls a computer a complex system designed to process data and perform tasks according to a set of instructions. Its objective is to perform computations, process data and execute tasks efficiently, like running word processors, browsers and games.

Interface components let people use the computer: input devices like the keyboard and mouse, and output devices like monitors and printers.

Processing components: the CPU does computations and executes commands. RAM is transient storage for the CPU, while a hard drive or SSD stores data permanently. Your book also lists the operating system and application software here.

Communication components connect the parts. The motherboard is the main circuit board. The system bus carries signals between the CPU and other parts, as three buses: data, address and control.

The environment is everything outside that interacts with the computer: the power supply, the network and peripherals such as scanners and external discs. A user types, the network carries data, and power keeps it all running.

Three groups of components: interface (in and out), processing (CPU, RAM, storage, software) and communication (motherboard, buses). Power, network and peripherals are the environment.

Key terms

RAM

Holding data and instructions the CPU is using now.

Storage

Keeping data and software for future processing.

Motherboard

Connecting all components with cables and circuits.

System bus

Carrying data, addresses and control signals between the CPU and other parts.

Short questions with model answers

1. Q1. Describe the main components of a computer system.

   • Interface.
   • Processing.
   • Communication.

   Interface, processing and communication components, as in section 1.4.2.

2. Q2. You double-click report.docx. What does your book say happens first?

   • Step 1: user action.
   • Step 2: input device.

   Your book prints only these first two steps (p. 14); ask your teacher for the rest of the path to the screen.

Common mistakes

• ✗ Calling RAM permanent storage.

  ✓ RAM is transient; the hard drive or SSD is permanent.

• ✗ Naming only the data bus as the system bus.

  ✓ Your book names three: data bus, address bus and control bus.

• ✗ Saying the operating system performs the calculations.

  ✓ The CPU calculates; the OS receives input from interface components and decides what to do.

MCQs

1. 1. What role does the Operating System (OS) play in a computer?

   1. (a) It performs calculations and executes instructions
   2. (b) It temporarily stores data for the CPU
   3. (c) It receives input from interface components and decides what to do
   4. (d) It provides long-term storage
   Show answer

   (c) Exercise MCQ 7 (p. 22); p. 13.

2. 2. Which of the following transports data inside a computer among different components?

   1. (a) Control unit
   2. (b) System bus
   3. (c) Memory
   4. (d) Processor
   Show answer

   (b) Exercise MCQ 10 (p. 23); p. 13.

3. 3. Which is transient storage for the CPU?

   1. (a) RAM
   2. (b) Hard drive
   3. (c) SSD
   4. (d) External disc
   Show answer

   (a) Processing components, p. 13.

4. 4. Which belongs to a computer's environment, in your book?

   1. (a) The CPU
   2. (b) The motherboard
   3. (c) RAM
   4. (d) The power supply
   Show answer

   (d) Section 1.4.4, p. 15.

5. 5. The three buses of the system bus are:

   1. (a) Input, output, storage
   2. (b) CPU, RAM, SSD
   3. (c) Data, address, control
   4. (d) LAN, WAN, Internet
   Show answer

   (c) Communication components, p. 13.

Quick revision

• A computer's objective is to compute, process data and execute tasks efficiently.
• Its components are interface, processing and communication components.
• Its environment is the power supply, the network and peripherals.