Encryption & Defragmentation

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Encryption Software

Encryption software is essential whenever sensitive data is being transferred or stored.

What is encryption?

Encryption is the "scrambling" of data.
It works by applying a special encryption algorithm to the data in the file.
Encryption processes are very mathematical processes. Strong encryption algorithms can be the result of years of professional research.

What is decryption?

Decryption is when an authorised party uses a special key to un-scramble the data.
The key prevents unauthorised users from accessing the data.

Encryption in operating systems

Good encryption utilities will work closely with the operating system to encrypt and decrypt files in real time as you need to access them.

Defragmentation Software

Defragmentation software is a common type of utility software.

Fragmentation

When files are written to secondary storage, they are not always written in one continuous block. They may be split up.
If a single file is stored in different places on a storage device, we say that the file is fragmented.
Fragmented files take longer to load.

Defragmentation

Defragmentation software reorganises the data on the storage device so that data from the same file is stored in adjacent blocks.
Defragmentation software will increase the performance of the computer.

Solid state drives

Solid state drives (SSDs) provide random access to data.
This means that fragmented data does not take any longer to load.
SSDs should never be defragmented because this will push the device towards its read/write cycle limit, which shortens its lifetime.

1Components of a Computer

1.1Structure & Function of the Processor

1.1.1Structure of the CPU

1.1.2Fetch, Decode, Execute Cycle

1.1.3Factors Affecting CPU Performance

1.1.4CPU Architecture

1.2Types of Processors

1.2.1CISC & RISC

1.2.2Multicore & Parallel Cores

1.3Input, Output & Storage

1.3.1Computer Systems

1.3.2Magnetic Storage

1.3.3Optical Storage

1.3.4Types of Optical Storage

1.3.5Types of Memory

1.3.6Flash Memory

1.3.7Virtual Memory

2Software & Software Development

3Exchanging Data

4Data Types, Data Structures & Algorithms

4.1Data Types

4.1.1Data Types

4.1.2Arrays & Strings

4.1.3Representing Numbers

4.1.4Binary Arithmetic

4.1.5Hexadecimal

4.1.6Converting Binary Numbers

4.1.7Floating Points in Binary

4.1.8Floating Point Arithmetic

4.1.9Bitwise Manipulation

4.1.10Character Sets

4.2Data Structures

4.2.1Arrays, Linked Lists & Queues

4.2.2Graphs, Hash Tables & Stacks

4.2.3Trees

4.3Boolean Algebra

4.3.1Computational Logic

4.3.2Boolean Logic

4.3.3Karnaugh Maps

4.3.4Boolean Identities

4.3.5Flip Flops & Adder Circuits

5Legal, Moral, Cultural & Ethical Issues

5.1Computing Related Legislation

5.1.1Data Protection Act (1998)

5.1.2Computer Misuse Act (1990)

5.1.3Copyright Designs and Patents Act (1988)

5.1.4Regulation of Investigatory Powers Act (2000)

5.2Moral & Ethical Issues

5.2.1Online Activity Tracking

5.2.2Censorship

5.2.3Cultural Issues

5.2.4Environmental Issues

5.2.5Layout, Colour Paradigms & Character Sets

6Elements of Computational Thinking

6.1Thinking Abstractly

6.1.1Abstraction

6.2Thinking Procedurally

6.2.1Decomposition

6.3Thinking Logically

6.3.1Pseudocode & Flow Diagrams

7Problem Solving & Programming

7.1Programming Techniques

7.1.1Programming Fundamentals

7.1.2Modularity

7.2Programming Construction

7.2.1Integrated Development Environments

7.2.2Testing

8Algorithms

8.1Algorithms

8.1.1Interpreting, Correcting & Completing Algorithm

8.1.2Sort Algorithms

8.1.3Insertion & Merge Sort

8.1.4Search Algorithms

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