Year 10 · ICT · Summer 2 · Website authoring and images; the Year 10 mock

Revision: theory topics 1 to 7

Exam practicePresent ▶

What this lesson covers

2.1 Input devices

Cambridge IGCSE ICT 0417 · Topic 2: Input and output devices · Paper 1

4.1b Types of network and cloud computing

Cambridge IGCSE ICT 0417 · Topic 4: Networks and the effects of using them · Paper 1

7.4 Implementation

Cambridge IGCSE ICT 0417 · Topic 7: The systems life cycle · Paper 1

You will learn to

Use the command word to decide what kind of answer a theory question needs.
Answer timed questions on theory topics 1 to 7.
Explain why one-word answers such as 'faster' or 'cheaper' rarely earn marks.
Evaluate your answers with the mark scheme and update your RAG list.

Success criteria

I can say the difference between Describe and Explain.
I can write an advantage that says what is better, and better than what.
I can colour each syllabus point red, amber or green from my marks.

The syllabus points for these sections

Describe the use of each input device in the syllabus.
Give an advantage and a disadvantage of each.
Choose a suitable input device for a given situation and justify the choice.
Name the right sensor for a measurement.
Compare Wi-Fi and Bluetooth.
Describe cloud computing and give advantages and disadvantages.
Compare the internet, an intranet and an extranet.
Describe LAN, WLAN and WAN and compare them.
Describe direct changeover, parallel running, pilot running and phased implementation.
Give advantages and disadvantages of each method.
Choose the most suitable method for a given scenario and justify it.

Key words

Say each word, then read what it means. Every one is in the glossary too.

Input device: Hardware that sends data or instructions into a computer.
Direct data entry (DDE): Reading data straight from its source with no manual typing.
Sensor: An input device that measures a physical quantity such as temperature.
Actuator: An output device, such as a motor or valve, that makes something move or happen.
OCR: Optical character recognition: turns a scanned image of text into editable text.
Barcode: A pattern of lines that stands for a number, read by a light beam.
Chip and PIN: A bank card chip read by a terminal; the user types a PIN to prove identity.
Trackerball: A pointing device where you roll a ball; the device stays still.
Network: Two or more devices connected so they can share data and resources.
IP address: An address that identifies a device on a network or the internet.
Switch: Connects devices on a LAN and sends data only to the right device, using MAC addresses.
LAN: Local area network: covers one building or site.
WLAN: Wireless LAN: devices connect by Wi-Fi.
WAN: Wide area network: covers a large area, joining many LANs.
Intranet: A private network for members of one organisation.
Extranet: Part of an intranet that authorised outsiders can reach.
Cloud computing: Storing data and running software on remote servers over the internet.
Systems life cycle: The stages used to create a new system: analysis, design, development and testing, implementation, documentation, evaluation.
Systems analyst: The person who studies the current system and plans the new one.
System specification: A list of the hardware and software the new system needs.
Check digit: An extra digit calculated from the other digits, used to detect input errors.
Data capture form: A paper or on-screen form used to collect data.
Test plan: A table listing each test, its data, the expected and actual outcomes and any remedial action.
Direct changeover: The old system stops and the new one starts immediately.
Parallel running: Old and new systems run together until the new one is trusted.
Pilot running: The new system is tried in one branch before the rest.
Phased implementation: The new system is introduced one part at a time across the organisation.

The explanation

Read it here, or open the study page below to go one step at a time with things to try.

Command words in ICT theory

Every question starts with a command word. It tells you what kind of answer earns the marks.

Command word	What it asks for	ICT example
State or Give	A short fact. No reason needed.	Give one input device used at a till. A barcode reader.
Identify	Name or pick out one thing.	Identify the implementation method that runs both systems: parallel running.
Describe	What something is like, or what happens, in order.	Pilot running: the new system is used in one branch first.
Explain	Why or how. Give a reason, joined with 'because' or 'so'.	A switch is more secure than a hub, because it sends data only to the right device.
Compare	How two things are alike or different. Mention both in each point.	An intranet is only for staff, but the internet is open to everyone.
Evaluate	Points for and against, then a conclusion.	Cloud storage for a school: pros, cons, then a judgement.

★Remember

As a rough guide, one mark needs one clear, separate point.

Answers that score

Short words like 'faster', 'cheaper' or 'easier' rarely score on their own. Say what is better, and compared with what.

Scores nothing	Scores
It is faster.	Scanning a barcode is faster than typing the number, so queues are shorter.
It is cheaper.	Video conferencing saves travel costs, because staff do not travel to meetings.
It is more secure.	Biometrics cannot be forgotten or shared like a password.

!Watch out

Link every answer to the scenario in the question. A general answer often loses marks.

Time, marks and the RAG list

Paper 1 (Theory) lasts 1 hour 30 minutes. It has 80 marks. 90 ÷ 80 is about 1.1 minutes per mark.

Do the timed questions in silence.
Mark them with the real mark scheme.
Write each missing point in a different colour.
Colour each syllabus point: red (cannot do yet), amber (makes mistakes), green (can do under time).
Revise the reds first.

!Watch out

Check the paper length on the current Cambridge 0417 syllabus for the year your pupils sit the exam.

2.1 Input devices

What an input device does

An input device lets data or instructions go into a computer.

Some are manual: a person operates them, like a keyboard. Others capture data automatically, like a sensor.

When you answer an exam question, name the device, say what it is used for, then give a reason linked to the situation.

e.g.Example

Weak answer: "A barcode reader is fast." Strong answer: "A barcode reader is faster than typing the product code, because the code is read in one scan, so the queue moves quickly."

Keyboards and numeric keypads

A keyboard is used to type text and commands. Most use the QWERTY layout.

A concept keyboard has flat keys with pictures or words. Fast-food tills use them.

A numeric keypad has only numbers and a few keys. It is on ATMs, chip and PIN terminals, phones and the side of large keyboards.

Device	Use	Advantage	Disadvantage
Keyboard	Typing documents, emails, data into forms	Fast, accurate entry of text for a trained typist; familiar to most users	Slow for people who cannot type; long use can cause RSI; takes up desk space
Numeric keypad	Entering PINs at an ATM, prices at a till, phone numbers	Faster than a full keyboard for numbers; small, so fits on a card terminal	Keys are small and can be hard to press; PIN can be seen by shoulder surfing

Pointing devices

A pointing device moves a pointer (cursor) on a screen and selects things.

A mouse is moved on a desk. A touchpad is a flat pad on a laptop: you move a finger on it. A trackerball is like an upside-down mouse: you roll the ball and the device stays still.

Device	Use	Advantage	Disadvantage
Mouse	Selecting icons and menus in a GUI; drawing	Faster to select options than using keyboard shortcuts; easy to use	Needs a flat surface; can cause RSI with long use
Touchpad	Pointing on a laptop	Built in, so no extra device to carry; works where there is no desk	Harder to control precisely than a mouse, e.g. for drawing
Trackerball	People with limited hand movement; control rooms; some medical equipment	Does not move, so needs less space and less wrist movement; easier for some disabilities	Not as fast as a mouse for most users; costs more

Remote controls, joysticks and driving wheels

A remote control sends infrared or radio signals to a TV, projector or air conditioner from a distance.

A joystick controls movement in games and flight simulators. A driving wheel controls steering in driving games and car simulators.

Device	Use	Advantage	Disadvantage
Remote control	Changing TV channel; controlling a projector or a multimedia system	Can be used from a distance, so the user does not need to move	Infrared needs a clear line of sight; small buttons hard for some people; easy to lose
Joystick	Games; flight simulators; controlling robot arms	Easier to control movement in any direction than with keys; feels realistic	Harder to use for selecting menus or typing
Driving wheel	Driving games and training simulators	More realistic than a keyboard, so training is more useful	Expensive; takes up space; only useful for one kind of task

Touch screens and light pens

A touch screen is a screen you touch to select options. It is used on phones, tablets, ATMs, information kiosks and self-service tills.

A light pen is a pen with a light sensor. You point it at a screen to draw or select. It is rare now and is used in some design and medical work.

Device	Use	Advantage	Disadvantage
Touch screen	Phones, ATMs, kiosks, self-service checkouts	Fast and intuitive, no training needed; no keyboard or mouse, so saves space	Screen gets dirty and scratched; limited options per screen; hard for some disabilities
Light pen	Drawing directly on screen; selecting on medical or design screens	More precise than a finger; no desk space needed	Can be tiring to hold up against a screen; not suitable for all screen types

Scanners, digital cameras and microphones

A scanner turns a paper document or photo into a digital image.

A digital camera takes photos and videos and stores them on a memory card.

A microphone turns sound into an electrical signal. Uses: video calls, voice recognition, recording.

Device	Use	Advantage	Disadvantage
Scanner	Digitising old photos and documents; with OCR, turning print into editable text	Faster than retyping or redrawing; makes a digital backup of paper	Quality depends on the original; large image files
Digital camera	Photos for websites, ID cards, reports	Images can be checked at once and deleted; easy to transfer to a computer	High-quality images use a lot of storage; good cameras are expensive
Microphone	Voice recognition, video calls, voice notes	Faster than typing for many users; hands-free	Background noise affects quality; voice recognition makes errors

Sensors

A sensor measures a physical quantity, such as temperature, and sends the reading to a computer. The data is usually analogue, so an ADC converts it.

Sensors take readings automatically and continuously, day and night. A person does not need to be there.

Sensor	Measures	Example use
Temperature	How hot or cold	Central heating, greenhouses, ovens
Light	Light level	Street lights turning on at dusk; phone screen brightness
Pressure	Force or weight	Burglar alarm mats; car airbags; checking tyre pressure
Moisture / humidity	Water in soil or air	Watering plants in a greenhouse; museums
Infrared / motion	Movement or heat from a body	Security lights; automatic doors
Sound (acoustic)	Noise level	Burglar alarms detecting breaking glass
pH	Acidity	Fish tanks; checking river pollution
Gas (e.g. CO2, oxygen)	Gas levels	Greenhouses; carbon monoxide alarms

?Why?

Advantage: readings are more accurate and more frequent than a person could take, and work in dangerous places. Disadvantage: a faulty sensor gives wrong data, and sensors cost money to install and maintain.

!Watch out

A sensor does not "control" anything. It only measures. The microprocessor decides and an actuator acts.

4.1b Types of network and cloud computing

Wi-Fi and Bluetooth

Both send data by radio waves, so no cables are needed.

Wi-Fi connects devices to a network and the internet over a range of about 30 to 100 metres.

Bluetooth connects two devices close together, usually under 10 metres, such as a phone and wireless earphones.

	Wi-Fi	Bluetooth
Range	Longer (about 30–100 m)	Short (usually under 10 m)
Data transfer rate	Faster	Slower
Number of devices	Many on one network	Few, usually pairs
Security	Better, with strong encryption (WPA2/WPA3)	Weaker; can be intercepted if left discoverable
Power use	Higher	Lower
Typical use	Laptops in a school, internet at home	Earphones, smartwatch, wireless keyboard, car hands-free

Cloud computing

Cloud computing means storing files and running software on remote servers, reached over the internet, instead of on your own computer.

Examples: online file storage and online office apps. A school might keep all student work in cloud storage.

The servers are owned by a cloud provider and kept in large data centres.

Advantages	Disadvantages
Files can be reached from any device, anywhere with internet	Needs a reliable internet connection; no internet means no files
Provider makes backups, so data is safe if your laptop breaks	Security and privacy depend on the provider; data could be hacked
Easy to share and work on the same file together	Ongoing subscription costs
Storage can be increased easily without buying hardware	Data may be stored in another country with different laws

Internet, intranet and extranet

The internet is a worldwide network of networks. It is public: anyone can connect.

An intranet is a private network inside one organisation. It uses the same technology as the internet, but only members (staff, students) can use it. Example: a school intranet with timetables and homework.

An extranet is part of an intranet that selected outsiders can reach with a password. Example: a supermarket lets its suppliers check stock levels.

	Internet	Intranet	Extranet
Who can use it	Anyone	Members of one organisation	The organisation plus authorised outsiders
Content	Public, not checked	Private, controlled by the organisation	Selected private content
Size	Worldwide	Usually one organisation	One organisation and its partners
Reliability of information	Varies a lot	More reliable, because it is managed	More reliable

!Watch out

The internet is not the same as the World Wide Web. The internet is the network. The web is the pages you reach over it.

LAN, WLAN and WAN

A LAN (local area network) covers one building or site, such as a school. Devices are connected by cables.

A WLAN (wireless LAN) is a LAN where devices connect by Wi-Fi through wireless access points (WAPs).

A WAN (wide area network) covers a large area, such as a country or the world. It joins many LANs. The internet is the biggest WAN. A bank with branches across Spain uses a WAN.

	LAN (cabled)	WLAN	WAN
Area	One building or site	One building or site	Cities, countries, worldwide
Connection	Cables	Radio waves (Wi-Fi)	Telephone lines, fibre, satellite, leased lines
Speed	Fast	Usually slower than cable; drops with distance and walls	Slower than a LAN
Security	More secure: need physical access to a cable	Less secure: signals can be picked up outside	Needs strong security
Advantage	Fast and reliable	Users can move around; no cables to trip over	Links offices far apart
Disadvantage	Cables are costly to install; users cannot move	Interference from walls and other devices	Expensive to set up and run

7.4 Implementation

Four ways to change over

Implementation means putting the new system into use. Staff are trained and data from the old system is transferred.

Direct changeover: the old system stops and the new one starts at once, for example over a weekend.

Parallel running: the old and new systems both run at the same time, until the new one is trusted.

Pilot running: the new system is used in one branch or department first. Once it works, it goes to the rest.

Phased implementation: the new system is brought in one part at a time, across the whole organisation.

e.g.Example

A chain of 40 supermarkets gets a new till system. Direct: all 40 shops switch on Monday morning. Parallel: every shop runs old and new tills side by side for a month. Pilot: one shop in Getafe uses it first, then the other 39. Phased: all shops get the new payments part first, then stock control a month later.

!Watch out

Pilot and phased are easy to mix up. Pilot = one place, whole system. Phased = whole organisation, one part at a time.

Advantages and disadvantages

Each method trades cost and speed against risk.

The key question: what happens if the new system fails?

Method	Advantages	Disadvantages
Direct	Cheapest: only one system runs and staff do the work once. Benefits are immediate. Fastest.	Highest risk: if the new system fails, there is no backup and work stops. Data could be lost. Staff must be fully trained before the switch.
Parallel	Lowest risk: if the new system fails, the old one is still working. Results can be compared to check the new system.	Most expensive: staff do every job twice, so extra staff or overtime are needed. Takes longest. Data entered twice can lead to errors.
Pilot	If it fails, only one branch is affected. Staff in the pilot branch can train others. Cheaper than parallel.	Slow to reach the whole organisation. If the pilot branch fails, it suffers on its own. The pilot branch may not be typical of the others.
Phased	If one part fails, only that part is affected and it can be fixed. Staff learn one part at a time.	Slow: takes a long time to fully implement. Parts of old and new systems must work together, which is hard. Costly to evaluate each phase.

?Why?

There is no best method. The right one depends on how bad a failure would be, how much money there is, and whether the system can be split into branches or parts.

Choosing the right method

Use direct when the system is small, simple, or the old system has already stopped working. Also when two systems cannot run side by side.

Use parallel when failure would be serious, such as payroll, banking or hospital records.

Use pilot when the organisation has many similar branches, such as shops or banks.

Use phased when the system splits into separate parts, such as a school system with attendance, marks and timetable modules.

e.g.Example

Try the toy. For each scenario, pick a method and read why. Scenario: a hospital moves patient records to a new system. Best answer: parallel running. A failure could put patients at risk, so the old system must keep working until the new one is proven.

!Watch out

In a 'choose and justify' question, the justification must link to the scenario. 'Parallel is safest' is weak. 'Parallel, because if the new payroll fails, 300 staff still get paid by the old system' is strong.

There is something to try for this step in the IGCSE library.

Study it

Open the study page and go one step at a time.

ICT topic 21

Check yourself

One question at a time. The reason shows after each answer.

Saved on this device.

Revision: theory topics 1 to 7

What this lesson covers

You will learn to

Success criteria

Key words

The explanation

Command words in ICT theory

Answers that score

Time, marks and the RAG list

What an input device does

Keyboards and numeric keypads

Pointing devices

Remote controls, joysticks and driving wheels

Touch screens and light pens

Scanners, digital cameras and microphones

Sensors

Wi-Fi and Bluetooth

Cloud computing

Internet, intranet and extranet

LAN, WLAN and WAN

Four ways to change over

Advantages and disadvantages

Choosing the right method

Study it

Website authoring

Images

File management

What a computer is

Networks and the internet

Digital life, law and ethics

Algorithms

Check yourself