JSS 1 First Term

Learning Objectives

• State the functions of the major parts of a computer.
• Explain how the parts work together to produce output.
• Trace a task from typing a name to printing it.
• Compare primary and secondary storage by function.

Input and Output Functions

An input device sends data and instructions into the computer. A keyboard types letters and numbers. A mouse points, clicks and selects. A scanner changes a printed page into a digital file. A microphone sends sound. A webcam sends a picture.

An output device presents the result. The monitor shows it on screen. A printer produces a paper copy. A speaker produces sound. A projector enlarges the screen for a class.

Soft copy means a copy shown on the screen.

Processing and Storage Functions

The processing function is done by the processor. It performs arithmetic and logical operations, and it follows instructions stored in memory. Without the processor, data would enter the computer and never be changed into a useful result.

Storage has two forms. Primary storage is temporary and very fast. RAM is the main example. Secondary storage is slower but permanent and larger. The hard disk, solid state drive, flash drive, memory card and optical disc are all secondary storage.

Arithmetic operation means a calculation such as addition or multiplication.

How the Parts Work Together

Consider a simple task. A learner types a name on the keyboard. The keyboard sends the letters to the processor through RAM. The processor processes the letters and sends the result to the monitor, where it appears. If the learner presses Print, the processor sends the result to the printer, which produces a hard copy.

The same task repeated shows the four stages. Input is typing. Processing is the work the processor does. Output is display or printing. Storage happens when the work is saved to the hard disk.

The Information Processing Cycle

Every task a computer performs follows the information processing cycle: input, processing, output and storage. Understanding this cycle helps you explain why a computer behaves in a particular way, and why a file that was never saved is lost when the machine is switched off.

Computer Hardware

Hardware is every physical part of the computer that you can touch. Inside the system unit the motherboard is the main circuit board, and every other part connects to it, which is why it is called the backbone of the computer.

The processor, or CPU, is the brain of the computer, and its speed is measured in gigahertz (GHz). RAM is the working memory that holds the programs and data in use, and it is cleared when the power goes off. The hard disk keeps the operating system, programs and files permanently.

Computer Software and the Operating System

Software is the set of programs and instructions that tell the hardware what to do. System software runs and manages the computer itself, and the operating system is its most important example. Application software helps the user perform a task, such as a word processor, a spreadsheet or a web browser.

The operating system is the first program to load when the computer is switched on. It manages the processor, the memory, the storage and the connected devices, and it provides the interface of icons, windows and menus that the user sees. Examples are Windows, macOS, Linux, Android and iOS.

Driver means a small program that lets the operating system communicate with a device.

Utility means a system program that performs maintenance tasks such as antivirus scanning.

Practical Work

1. Type a short paragraph on the computer, save it, then print it. Record what happened at each stage of the information processing cycle.
2. Write the steps involved from pressing a key to the letter appearing on screen.
3. Compare the speed of opening a file from RAM with opening one from the hard disk. Record which is faster and explain why.
4. Record the size of a folder and a single file to show how secondary storage holds large amounts.

Scenario-Based Questions

1. A pupil types an assignment for two hours but forgets to save it, then the computer is switched off. Explain which stage of the information processing cycle was missed and what happens to the work.
2. Explain why a computer with a slow hard disk is described as slow even when the processor is new.
3. Describe how a scanner, the processor and the printer work together in copying a page.
4. Give one reason RAM is called primary storage and one reason a hard disk is called secondary storage.
5. A computer displays the result of a calculation but cannot print it. Name two parts that could be faulty.
6. Write the information processing cycle as a flow diagram and label each stage.
7. Explain what would happen if a computer had no output device.