Definition of a Computer System

Lesson Objectives

By the end of the lesson you should be able to:

1. Define a computer system
2. State and explain the components of  a Computer System

Definition of a Computer System

A computer system refers to a collection of computer components that function as a whole to achieve a desired goal

Components of Computer Systems

Computer hardware - refers to physical tangible parts of a computer

Computer hardware is categorised into:

• input devices
• output devices
• central processing unit
• storage devices

Software - refers to a set of instructions that guides the computer to perform certain tasks

Software is categorised as:

• System Software
• Application software

Liveware/Orgware - refers to the computer user

Computer Hardware Lesson I

Lesson Objectives

By the end of the lesson you should be able to:

1. Define input devices
2. Describe variuos types of input devices

Computer Hardware

Input devices

Input devices are hardware components used to enter data into a computer. These devices convert data into machine readable form so as to be processed by the computer. They are classified as:

1. Pointing devices: These are devices used to controller a pointer or cursor on the screen. Examples of pointing devices include: mouse,joystick, laptop touchpad, stylus,
2. Keying devices: These are devices used to enter data into a computer by used a set of keys. They convert data into binary form that can easily be processed by the computer. Examples of keying devices are: keypads and keyboards
3. Scanning devices/Scanners:This captures data from an object and converts it into binary form that can be understood by the computer for processing purposes. There are two types of scanners, that is, Optical and magnetic scanners

Computer Hardware Lesson III

Lesson Objectives

By the end of this lesson you should be able to:

• State and explain various special purpose memories
• Define software
• classify software into various categories

Special Purpose Memories

There are three types of special-purpose memories:

1. Buffers
2. Registers
3. Cache Memory

Buffers

These are memories found within input and output devices. They hold data awaiting processing or data that has been processed to free the CPU.

Registers

Registers are special-purpose memories located inside the CPU.

Examples of registers

• The accumulator that holds the result of the last processing step of the ALU
• The Address register that holds the next piece of data waiting to be processed
• The instruction register temporarily holds an instruction just before it is interpreted into a form that the CPU  can process.
• Storage register that temporarily holds a piece of data that is on its way to and from the CPU and the main memory

Cache memory

A special memory found within the processor used to temporarily hold frequently accessed data and instructions that the processor is likely to reuse.

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Computer Software

Computer software refers to a set of instructions that guides the computer on how to perform specific tasks.

Software Classification According to Purpose

• System software
• Application Software

System Software

This software is designed to manage system resources and avail them to the user.

System software includes:

• operating system
• firmware
• utility software
• network software

An operating system is system software that manages the computer hardware and provides a platform for the installation of application software

Firmware refers to the tangible electronic component of a computer with embedded  software for example BIOS in ROM

Utility software is a system software meant to maintain, optimize, and configure a computer.

Networking software is meant to facilitate communication  between two or more computers on a network e.g Network Operating System

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