## Revision

This is revision for the end of year examination in computer science.

Just because there is a topic here does not mean that it will be in the examination.

Similarly, if there is a topic that is not mentioned then that does not mean that it will not be examined.

## Binary

You are expected to know how ro convert between the three number bases in computing, Binary, Denary and Hexadecimal.

Here is a quick way of converting from Decimal to binary. Start with the number (106) and divide it by two, the remainder is 0. Now the number is 53 and when divided by two the remainder is 1. Keep doing this until there is nothing left. The answer is the remainders, backwards. Neat huh? Try it, it works.

106 | 01101010 | ||

106 | 0 | ||

53 | 1 | ||

26 | 0 | ||

13 | 1 | ||

6 | 0 | ||

3 | 1 | ||

1 | 1 | ||

0 | 0 | ||

You may be asked to convert from any of binary, denary and hexadecimal to binary, denary or hexadecimal.

This is binary and decimal

This is binary and hexadecimal.

## Glossary

binary | A number system that contains two digits, 0 and 1. Also known as base 2. |
---|---|

bit | The smallest unit of data in computing represented by a 1 in binary. |

CPU | Central processing unit - the brain of the computer that processes program instructions. Also called a microprocessor. |

denary | The number system most commonly used by people. It contains 10 unique digits 0 to 9. Also known as decimal or base 10. |

floating point | A data value in computer programming used to denote decimal numbers. |

integer | A whole number - in computing, a data type which represents signed (positive) or unsigned (negative) whole numbers. |

IP address | A unique address for each computer device on a network. |

octillion | 10 to the power of 27. A thousand quadrillion. |

overflow | An overflow error is caused when the processor does not have enough bytes available to process an instruction. |

PC | Personal computer. |

pi | Pi is the ratio of a circle's circumference to its diameter. A number with an infinite number of decimal places, starting with 3.14. |

register | The section of high speed memory within the CPU that stores data to be processed. |

signed | A signed number has a positive or negative indicator. |

word size | The size of an instruction a CPU can process. A 16 bit process can process words of up to 16 bits. |

## Set work

## Useful links (AQA Guides)

- Arithmetic operations in a programming language
- Boolean operations in programming languages
- Data structures (Arrays)
- Data structures (records)
- Data structures (Two-dimensional data structures)
- Data types
- Data validation and authentication
- Huffman code
- Input/output file handling
- Pseudo-code
- Programming concepts (Iteration)
- Programming concepts (Selection)
- Programming concepts(Variables and constants)
- Run-length encoding
- Random numbers
- Relational operations
- Subroutines
- String handling
- Structured programming
- Testing

## Questions

These are questions that relate to the AQA guides above.

## Revision

These are some revision topics and example questions that will aid revision for the year 10 examination on 23rd June 2017. Just because it is in this list does not mean that its in the exam and if it is not in the list it does not mean that the topic is not inthe exam.

- Revision topic - Binary
- Revision topic - Cybersecurity
- Revision topic - E-waste
- Revision topic - Hardware
- Revision topic - High and low level languages
- Revision topic - Huffman Code
- Revision topic - Images
- Revision topic - Logic
- Revision topic - Networks
- Revision topic - Operating systems
- Revision topic - Pseudocode
- Revision topic - Social Engineering
- Revision topic - Software
- Revision topic - Sound

## Mock examination

Here are the answers to the mock examination that you took in the summer.

For many students the objective here is to understand how to answer questions, to see where silly mistakes were made that cost easy marks and to appreciate how the examiner can aske questions relating to the theory that you already know.

## Coursework

Here is the information regarding your coursework as well as some worked examples to show you how coursework should be written up.

The coursework will be done twice, once with the example task for practice and then the real NEA task. You will only have 20 hours in which to complete the real task; there __cannot__ be any extra time given.

- Teacher's notes - regading coursework help and guidance that can be given.
- Sample task 1 - area trainer
- Sample task 2 - cows and bulls.
- Solution 1 - cows and bulls
- Solution 2 - cows and bulls
- Sample task 3 - simple card trick
- Solution 3 - simple card trick