Lesson Objectives By the end of this lesson you will be able to: (a) Define hardware, giving examples (b) Define software, giving examples (c) Describe the difference between hardware and software (d) Identify the main components of a general-purpose computer: central processing unit, main/internal memory (including ROM and RAM)

Hardware or Software? 1. Printer - 2. Adobe Acrobat - 3. Windows 7 - You have 2 minutes to discuss with the person sitting next to you, which is hardware and which is software… 1. Printer - 2. Adobe Acrobat - 3. Windows 7 - 4. Motherboard - 5. Scanner - 6. Graphics Driver - Hardware Software Software Hardware Hardware Software

Definitions… Hardware is a general term for the physical components that make up a computer system. Write down 3 examples of hardware. Software is a general term for the programs that control the computer system. Write down 3 examples of software. For a computer system to be useful it has to consist of both hardware and software.

With the person sitting next to you... You have 2 minutes to discuss and label the diagram below: Backing Storage Input Main Memory Process Output

Title: Components of a Computer System Draw the following diagram in your book: INPUT PROCESS OUTPUT MAIN MEMORY BACKING STORAGE

Used to convert images on paper into digital format Matching Up… In pairs match each device to it’s type and description For example: Scanner Input Used to convert images on paper into digital format

Answers… Keyboard Input It is made up of buttons called keys. The keys are arranged into different sections. The most common type is known as a QWERTY. Mouse A pointing device which controls what happens on the screen. The left button is usually used for selecting and the right button brings up menus. Monitor Output The pictures displayed on it are made up of pixels. The two most commonly used ones are known as CRT’s and TFT’s. Printer These are used to create a hard copy of your work. Most produce their output on paper. They come in colour and black and white. Central Processing Unit Process The brain of the computer where all the searching, sorting, calculating and decision making takes place. RAM Main Memory This is volatile memory. The data is held on a chip, but only temporarily. The data disappears if the power is switched off. ROM The data stored is not erased when the power is switched off - it is permanent. This is called non volatile memory. Stick Backing Storage They are small, lightweight and rewritable. They consist of a small printed circuit board which is encased in plastic or metal casing. DVD They can be written to once and are used in all modern computers. They have a large storage capacity.

Components of a Computer System You will be looking at input, output and storage devices later in the course. For the rest of this lesson we will look at the Central Processing Unit (CPU) and Main Memory. What do you think the CPU does?

Central Processing Unit The CPU is the brain of the computer. It is the device that carries out software instructions. The Pentium processor made by Intel is an example of a CPU. CPUs usually plug into a large socket on the main circuit board (the motherboard) of a computer. They get very hot when they are operating so usually have a large fan attached to their top to keep them cool. No Past exam Questions

Main Memory The CPU needs to store data whilst its carrying out the processing required. The data or instructions that are to be processed by the CPU must be placed into main memory. Memory can be classed into two types: RAM and ROM

Random Access Memory (RAM) Random Access Memory (RAM) is the part of the computer that temporarily stores the instructions that the computer is running, and the data it is processing. RAM is a volatile storage device. This means that if the computer’s power is turned off the contents of RAM disappear and are lost. When a computer is in use, its RAM will contain: The operating system software The application software currently being used Any data that is being processed

RAM – Notes from Mark Schemes Random Access Memory A temporary store of data Holds the date that is currently being used by the user It is volatile so data is lost when the computer is turned off It can be read from or written to The data in RAM can be changed It is needed so that users are able to make changes to the data they are working on/to store the program or data they are currently using

Read-Only Memory (ROM) Read-Only Memory (ROM) is used in most computers to hold a small piece of software: the 'boot up' program. This 'boot up' software is known as the BIOS (Basic Input Output System), it checks the computer’s hardware and then loads the operating system. ROM is non-volatile storage. This means that the data it contains is never lost, even if the power is switched off.

ROM Notes from Mark Schemes Read Only Memory It is non-volitile so not lost when the computer is turned off Stores things such as: BIOS, Programs in washing machine, program instructions for games The data cannot be changed It is used so that programs/coding/software can be stored permanently/cannot be changed

Lesson Summary This lesson we looked at: What hardware and software are Some examples of them The main components of a computer system The CPU Main Memory – RAM and ROM

Plenary Questions – What is… Hardware = Software = CPU = Physical Components Programs The Brain

Past Exam Questions

RAM – So that users are able to make changes to the data they are working on/to store the program or data they are currently using (1) ROM – So that programs/coding/software can be stored permanently/cannot be changed (1) [3]

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