Teach Computing

Revision notes, activities, lesson plans, teaching ideas, and other resources for GCSE, A-Level, and IB Computer Science teachers and students.

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Device specifications

Device Specifications is a simple site with a huge database of smart phones...

Smart phone specs explained

This excellent site is a detailed guide to smart phone specifications, expl...

Software as a Service (Saas)

This short video gives an overview of Software as a Service (SaaS), which s...

Amazon EC2 - Elastic Cloud Server

Amazon Elastic Cloud (Amazon EC) is a good example of Infrastructure as a S...

Changeover notes

IGCSE ICT provide short but clear notes and diagrams covering the different...

CommandPoint CAD

CommandPoint by Northrop Grumman offers a range of CAD systems for various ...

CAD+911 System

TriTech Software Systems is a company that specialises in Computer Aided Di...

London Ambulance CAD failure

The 1992 London Ambulance Service CAD failure is probably the most notoriou...

Washington State 911 Failure

A 911 emergency telephone system in Washington State and Oregon shut down f...

Resources discount offer

3.3 Hardware

Click here for recommended Cambridge A-Level Computer Science textbooks.

3.3.1 Logic gates and circuit design


XOR and Half-Adder

This video starts by recapping the truth table for an exclusive-OR (XOR) gate, and then goes on to show how its properties can be used to help create a half-adder in conjunction with an AND gate. The video helps demystify the concept by building up the half-adder and explaining with examples why an additional gate is needed.

Updated: 2015-04-29

3.3.2 Boolean algebra

Boolean expression simplification

Logic Simplification Examples Using Boolean Rules

This is an excellent video which goes clearly through the individual steps of simplifying Boolean expressions. The video starts with a clear list of simplification rules and explains why they work. There are then two examples, complete with logic circuit diagrams, which are worked through line by line until they are fully simplified. This is probably the clearest explanation of Boolean simplification I have seen. (The video is a lot better than the screenshot makes it look!)

Updated: 2015-11-24

3.3.3 Karnaugh Maps

3.3.4 Flip-flops

3.3.5 RISC processors

3.3.6 Parallel processing

CERN Grid Computing

CERN Grid Computing system

This brief tour of the CERN computer grid gives a good overview of the computing system and the power available.

The second video features interviews with CERN employees who explain how the grid computing system works and how the data is transmitted to and processed by multiple tiers of computers spread across Europe.

Updated: 2015-05-27