Cambridge International AS & A Level ICT: every topic, by paper

Distinguish data and information.

Data are raw facts without meaning; information is data processed and given context so it has meaning.

Distinguish direct and indirect data sources.

Direct: collected first-hand for the purpose (surveys, observation). Indirect: collected for another purpose and reused (e.g. electoral register).

Give four factors affecting the quality of information.

Accuracy, relevance, age (up to date), completeness, level of detail.

What is a mainframe computer?

A large, powerful computer used by organisations for bulk data processing.

What is a supercomputer used for?

Complex calculations such as weather forecasting and scientific simulations.

Give three features of mainframes.

High reliability and uptime, huge throughput of transactions, and backward compatibility with older software.

Distinguish monitoring and control systems.

Monitoring systems record and display readings; control systems also act on them to change conditions.

Name four sensors used in monitoring and control.

Temperature, light, pressure, humidity, moisture, pH, infrared, sound.

Why is an ADC needed?

Sensors produce analogue signals that must be converted to digital for the computer.

What is e-safety?

Using the internet safely and responsibly, protecting personal data and wellbeing.

Give three ways to stay safe online.

Don't share personal information; use privacy settings; only use trusted websites; don't meet online contacts alone.

What is phishing?

Fraudulent emails that try to trick users into giving personal details.

What is the digital divide?

The gap between people who have access to modern IT and the internet and those who do not.

Give three causes of the digital divide.

Cost of devices and connection, lack of infrastructure, lack of skills (also age and disability).

How does geography cause a digital divide?

Rural areas often have poor broadband or mobile coverage compared with cities.

What is a LAN?

A local area network covering a small area such as a building.

What is a WAN?

A wide area network covering a large geographical area, e.g. the internet.

What is a WLAN?

A wireless LAN using radio waves (Wi-Fi) to connect devices.

What is an expert system?

A computer system that mimics the decision-making of a human expert in a specific field.

Name the main components of an expert system.

Knowledge base, rules base, inference engine and user interface (plus explanation system).

What is the knowledge base?

A store of facts about the specialist area, collected from experts.

Distinguish relative and absolute cell references.

Relative references change when copied; absolute references ($A$1) stay fixed.

What does =SUMIF(A2:A20, "Red", B2:B20) do?

Adds the values in B2:B20 where the matching cell in A2:A20 is "Red".

What does COUNTIF do?

Counts cells in a range that meet a condition.

What is a flat-file database?

A single table of data.

What is a relational database?

Data stored in several linked tables to reduce redundancy.

Distinguish primary and foreign keys.

A primary key uniquely identifies each record; a foreign key links to the primary key of another table.

What is sampling rate?

The number of sound samples taken per second (Hz).

How does a higher sampling rate affect sound files?

Better quality but larger file size.

What is bit depth for sound?

The number of bits stored for each sample; more bits give more accurate amplitude values.

What is augmented reality?

Overlaying computer-generated images on a view of the real world.

What is virtual reality?

A fully computer-generated environment the user can interact with, usually through a headset.

What is 3D printing?

Building objects layer by layer from a digital model.

What is e-commerce?

Buying and selling goods or services online.

Give two advantages of online shopping for customers.

Shop 24/7 from anywhere; compare prices easily; wider choice.

Give two disadvantages of online shopping for customers.

Can't see or try goods; delivery delays; risk of fraud.

What is email?

Electronic messages sent over a network.

What is VoIP?

Voice over Internet Protocol: making voice calls over the internet.

Give two advantages of video conferencing.

Saves travel time and cost; people in different locations can meet face to face.

Name the stages of a project life cycle.

Initiation, planning, execution, monitoring and control, and closure.

What happens at project initiation?

Goals, scope, feasibility and stakeholders are identified.

What is a Gantt chart?

A bar chart showing tasks against time, their durations, overlaps and milestones.

Distinguish bitmap and vector graphics.

Bitmaps are made of pixels; vectors are made of mathematically defined shapes.

Why do vector graphics scale without losing quality?

Shapes are redrawn from their definitions at any size.

What is resolution in bitmap images?

The number of pixels, often given as pixels per inch.

What is mail merge?

Combining a template document with a data source to produce personalised documents.

What are merge fields?

Placeholders in the master document that are replaced by data from the source.

How can mail merge select only some records?

By filtering the data source, e.g. only customers in one city.