Entry Level Computing

Revision Booklet

Content Hardware

– Components of a computer– Basic function of the common internal components of a

computer– Basic functions of common peripherals

Software– Operating system and its functions– Application and system software– System utilities

Logic– Convert between denary and binary numbers– Logic gates AND, OR and NOT– Sequence instructions into a logical order

HardwareComputer

hardware refers to the physical parts or components of a computer.

Input devicesAn input device is any piece of computer

hardware used to provide data to a computer system.

Examples include:– keyboard– mouse– scanner– digital camera– webcam– microphones

Input devicesDevice Use

Mouse Moving around a computer.

Keyboard 

The most common way of quickly typing in text into a computer.

Touch screen Moving around a computer or applications using your hands instead of a mouse.

Scanner Captures images from photographic prints, posters, magazine pages, and similar sources for computer editing and display. 

Camera Produces digital images that can be stored in a computer and displayed on screen.

Microphone This would be used to make recordings or as voice control – giving the computer commands.

Output devicesAn output device is any piece of

computer hardware used to communicate the results of data that has been processed.

Examples include:– monitor– printer– Speaker/headphones

Exam tip:Make sure that you can

identify the basic functions of different

devices

Output devicesDevice Use

Printer Used for producing a hard copy of information which can be taken away from a computer.

Touch screen Used for interacting with a computer.

Speakers/headphones

Used for hearing sounds, music.

Projector Displaying information from a computer for an audience on a large screen.

Monitor Used for displaying information.

Storage devicesA storage device is a piece of computer

equipment which can be used to store data.

Examples include:– hard disk drive– DVD/CD/Blu-Ray– USB Flash drive

A hard disk drive (HDD) is a data storage device used for storing and retrieving digital information using rapidly rotating disks (platters) coated with magnetic material.

Exam tip:Make sure that you can identify which devices

are input, output or storage.

Practice question 1Which is the odd one out?

Practice question 2

Put a tick() to indicate whether the device is input or output:

Device Input Output

Mouse

Speakers

Digital Camera

Scanner

Printer

Practice task 3Which two of these items are storage devices? Put ticks() in two of the boxes.

Item Tick the correct answer

KeyboardDVDMonitorHard diskPrinter

Internal components of a computer

Motherboard or logic board is the main circuit board in the computer.

It contains many components like the RAM, CPU, expansion slots and the heat sink.

The motherboard connects all the peripherals together.

Peripheral – a computer device that is not part of the CPU. It can be external (e.g. keyboard, mouse, printer or scanner) or internal, such as a DVD drive.

Central Processing Unit (CPU)

The CPU (Central Processing Unit) is the part of a computer system that is commonly referred to as the "brain" of a computer. The CPU is also known as the processor.

The CPU is where processes such as calculating, sorting and searching take place. Whatever is done on our computers, such as checking emails, playing games and doing homework, the CPU has processed the data we use.

Random Access Memory (RAM)

RAM is the main memory that stores programs and data currently being used by the computer.

RAM is a type of volatile memory which means that it requires electricity to store data, so when the computer is powered down all the memory is wiped.Here are some examples of what's stored in RAM: the operating system applications the graphical user interface

(GUI)

Read Only Memory (ROM) ROM (read only memory) is a flash

memory chip that contains a small amount of non-volatile memory.

ROM is memory that cannot be changed by a program or user.

ROM retains its memory even after the computer is turned off. For example, ROM stores the instructions for the computer to start up when it is turned on. Exam tip:

Make sure that you know the difference between RAM and

ROM

Power supplyThe power supply unit supplies all the

computer components with electricity

Heat sink and fan One of the main problems with computers are that

they can overheat easily. To stop this problem, fans are added to cool the computer down.

The main fan is positioned on the CPU because the CPU is prone to overheating. Firstly, a thermal compound is put on top of the CPU followed by the heat sink, and the fan is placed on top of it.

A heat sink is made out of metal and draws heat away from the processor.

Adapter cards (Expansion cards)

On the motherboard, there are expansion slots. In these expansion slots go several printed circuit boards, or adapter cards as they are most commonly known.

The sound card is an adapter card that allows the computer to have extended sound capabilities, and for sound components to be used, for example, headphones.

The video or graphics card is an adapter card that allows the computer to show graphics on the monitor.

Practice task 4a) CPU stands for ______________ ____________ ________.b) RAM stands for _____________ ___________ _______. It

is (permanent/temporary) memory where the computer stores all of the programs and data whilst they are being used.

c) ROM stands for ____________ ___________ _______. It is (permanent/temporary) memory that the computer uses when it is booting up.

d) The _______________ connects all the computer components together.

e) All the processing or work done on a computer is performed by the _______________.

SoftwareSoftware is the name given to

programs that run on a computer.There is a close relationship between

hardware and software. Without software, hardware is very limited and without hardware, software would not be able to run. They need each other.

Two main types of software

Systems softwareApplications software

Systems softwareSystems software helps run and

maintain the computer. It includes the operating system, drivers

and utility software.

Operating system (OS) The biggest part of systems software is the operating system. It

is an essential part that allows other systems software, and application software, to communicate with hardware.

The operating system is needed to perform a number of tasks:– it provides a user interface– manages the hardware resources– manages the use of memory– manages the opening, closing, saving and deleting of files– most operating systems have features that look after the

security of the computer with usernames and passwords. Examples of operating systems include Windows, Linux, Mac

OSX, Android and iOS.

Application softwareApplication software is used to carry

out tasks on a computer, such as writing an email, making a poster, doing homework and messaging friends.

Some of the applications we might use to do this include a word processor, web browser and graphics software.

Application software categories

Word processors and desktop publishing software

Spreadsheet and database software Multimedia software Presentation and slideshow software Image editing/graphics manipulation software Video editing software Communications software Gaming software Web browsers Apps for portable devices

Exam tip:Make sure that you

know the uses of the different application

software

Utility softwareUtility software is system software

designed to help analyse, configure, optimise or maintain a computer.

Categories:– Computer security– Disk organisation– System maintenance

Computer Security Antivirus – computer software used to prevent, detect and

remove malicious software Spyware protection – computer software used to detect

and remove spyware from the computer Firewall - is a network security system that controls the

incoming and outgoing network traffic based on applied rule set.

Spyware is the generic name we give to programs

that contain additional functionality designed to

secretly monitor your activities on your computer.

A computer virus is a harmful computer program

designed to damage a computer’s systems files.

Disk Organisation Formatting disk is the process of preparing a data

storage device such as a hard disk drive, solid-state drive, or USB flash drive for initial use.

File transfer is the movement of one or more files from one location to another.

Disk cleaners are computer programs that find and delete potentially unnecessary or unwanted files from a computer. The purpose of such deletion may be to free up disk space, to eliminate clutter or to protect privacy.

Defragmentation can detect computer files whose contents are scattered across several locations on the hard disk, and move the fragments to one location to increase efficiency.

System Maintenance System information and diagnosis. This is very useful

for people if they need to know the details of the system, perhaps to see if an application they are considering getting will be compatible. These utilities will also test the system if there are any problems.

A System clean-up tool will search the computer for settings which are no longer needed or for programs which are slowing down the computer. It can help improve the performance and speed up the boot-up time so that the computer starts up much faster.

Automatic updates help to ensure that your system is protected from possible threats or security loopholes that could be exploited by malicious programs or people in order to gain access to your system.

Practice task 5a) John has noticed that someone keeps accessing his files over the

internet and he has not given them permission. What does he need to do to prevent this from happening again?

Put a tick in the correct box.

Tick the correct answer()

Create a backup of his files

Do a system restore

Install a firewall and make sure it is configured properly

Run a virus scan

Practice task 61. To publish a magazine, ______ software would be best.

1. Word processing2. Desktop publishing3. Spreadsheet4. Presentation

2. Maria is a sales rep calling on up to 20 businesses a week. To keep track of her appointments and her clients’ addresses and phone numbers, she should use a _____ software.1. Word processor2. Database3. Photo editing 4. Multimedia

3. Android is an example of an operating system. TRUE or FALSE?

Bits and binaryComputers use binary - the digits 0 and 1

- to store data.A binary digit, or bit, is the smallest unit of

data in computing. It is represented by a 0 or a 1. 

Binary numbers are made up of binary digits (bits), e.g. the binary number 1001.

Binary and Denary The binary system on computers uses

combinations of 0s and 1s. In everyday life, we use numbers based on

combinations of the digits between 0 and 9. This counting system is known as decimal, denary or base 10.

A number base indicates how many digits are available within a numerical system. Denary is known as base 10 because there are ten choices of digits between 0 and 9. For binary numbers there are only two possible digits available: 0 or 1. The binary system is also known as base 2.

Converting between denary and

binaryAll denary numbers have a binary

equivalent and it is possible to convert between denary and binary.

Practice task 7a) Convert the denary number 7 to binary.

__________b) Convert the binary number 0011 to denary.

__________c) Convert the denary number 15 to binary.

__________d) Convert the binary number 0010 to denary.

__________e) Convert the denary number 5 to binary.

__________f) Convert the binary number 0111 to denary.

__________

Logic GatesThere are different types of logic gates, which one

you use depends on what the gate is required to do:

NOT OR

AND

OR gateAn OR gate will give a high output if any

of the inputs is high.

AND gateAn AND gate will give a high output only

if all of the inputs are high.

NOT gateA NOT gate is slightly different because it

has just one input. It will give a high output if the input is low.

Sequencing of instructions

An algorithm is a plan, a set of step-by-step instructions that a computer follows to solve a problem.

To solve the problem, the instructions have to be followed in the right order.

If the instructions are not carried out in the right order, you won’t get the result you expected.

For example:A very simple algorithm for brushing teeth

might consist of these steps:– put toothpaste on toothbrush– use toothbrush to clean teeth– rinse toothbrush

Each step is an instruction to be performed.

Sequencing is the order in which the steps are carried out.

Why is sequencing important?

It is crucial that the steps in an algorithm are performed in the right order - otherwise the algorithm will not work correctly.

Suppose the steps for the teeth-cleaning algorithm were in this sequence:1. use toothbrush to clean teeth2. put toothpaste on toothbrush3. rinse toothbrush

A toothbrush would still be used to clean the teeth and toothpaste would still be put on the brush. But because steps 1 and 2 are in the wrong sequence the teeth wouldn’t get cleaned with the toothpaste, and the toothpaste would be wasted.

A human would realise they had forgotten to add toothpaste at the start of the process, but a computer would not know that anything was wrong.

Practice task 81. The logic gate that will have HIGH or 1 as its output when any

one of its inputs is high is:a) NOT gateb) AND gatec) OR gate

2. What input values will cause an AND logic gate to produce a HIGH output?a) All inputs are HIGHb) At least one input is HIGHc) At least one input is LOWd) All inputs are LOW

3. State the name of the logic gate shown

Answers to practice tasks1. Keyboard2. Mouse (Input), Speakers (output), Digital Camera (input), Scanner

(input), Printer (output)3. DVD and hard disk4. a.) Central Processing Unit b.) Random Access Memory,

temporary c.) Read Only Memory, permanent d.) Motherboard e.) CPU or processor

5. a.) Install a firewall and make sure it is configured properly6. 1.) B 2.) B 3.)True7. a.) 0111 b.) 3 c.) 1111 d.) 2 e.) 0101 f.) 7 8. 1.) OR gate 2.) All inputs are HIGH 3.) OR gate