1. GCSE Computer Science
Unit 1 - Revision

2. CPU - Components

3. CPU Number of cores – how does it affect performance?
Processor speed – what is the negative for increased speed?
Cache memory – where located?
Reduced Instruction Set Computer (RISC) and Complex Instruction Set Computer (CISC). Compare speed and chance of overheating.

4. Computer Memory Permanent Volatile Data can be changed Speed
Permanent
Volatile
Data can be changed
Speed
Cache memory 

ROM

RAM 
Flash memory 

5. Secondary Storage Flash drive
Solid State Drive (SSD) - could be in computer. Faster, less power consumption.
Magnetic Tape (back up networks)
Magnetic – hard drive, tape
Optical – CD, DVD, etc.
Cloud storage

6. HCI – User interface Graphical User Interface – WIMP, Menu Driven
Command Line
Voice
Touch Screen

7. Binary How many bits are in a byte?
What are the largest and smallest denary values that can be made using 8 bit binary?
Convert 57 to 8 bit binary.
Convert to denary.

8. Hex What base is hexadecimal? Convert 179 to hexadecimal.
Convert 2D to denary.
Convert E3 to binary.
Convert to hex.
Why is hex used by technicians rather than binary?

9. Characters, Images, Sound
Compare ASCII and Unicode. Explain the advantages of Unicode compared to ASCII.
If an image is 10 pixels wide by 40 tall, and it is black and white, state the file size in bytes.
What affect does adding colour have to the file size?
State three items of metadata.
What does increasing the sample rate of the sound have on quality and file size?

10. Instructions Opcode - instruction
Operand – value or memory location of value

11. Logic Gates AND – both input must be 1 for output of 1
NOT – reverses input, e.g. 1 becomes 0
OR – either input must be 1 for output of 1
Complete the truth table below A
NOT A B
NOT A AND B 1

12. Data Types String ‘hello world’ Real – 34.23 Integer - 78
Character – ‘s’
Boolean - True/False

13. Data Types
State the most appropriate data types for the following fields.
Name – ‘Daniel James’
Year – 10
Form – ‘B’
Form Tutor – ‘Mr Smith’
Computer Science Effort Grade (A-E) – ‘A’
Average Test Mark – 78.66
Resit paper? – No
Student Ref – ‘bish1034’

14. Disk Organisation File transfer Formatting Compressing System restore
De-frag
Control Panel
Virus Protection
Firewall

15. Operating System Peripherals Printing Backing storage Compression
De-fragmentation
RAM
Processes / Software
Security

16. Defrag tool, Virus checker
What is the disadvantage of a fragmented disk?
Explain the process of defragging the disk.
State three functions of a virus checker.

17. Application Software
State an example of use for School awards evening:
Word processor
Database
Spreadsheet
Drawing package
Presentation software

18. IP and MAC address What is an IP address?
An IP address (Internet Protocol address) is the unique identification number given to every device that is connected to the internet.  It represents the unique location on which you are connected to the internet, allowing devices all over the world to communicate with each other.
If you take your laptop to McDonalds and connect to the internet, the IP address will differ from when you connected to the internet in Starbucks.  This is because the location you are using to connect to the internet has changed.
An IP address may look like:

19. IP and MAC address What is a MAC address?
A MAC address (Media Access Control address) is a unique number that identifies the actual device that is connected to the internet or network.
A MAC address does not change when you connect to the internet from different locations, it is part of the network interface card (NIC) inside your device.
A MAC address is made up of 48 bits, shown as 6 groups of hexadecimal digits.
A MAC address may look like: E A6 B0 68

20. IP and MAC addresses
What is the difference between an IP and MAC address?

21. DNS – Domain Name System Server
Explain the steps involved when entering a web address (e.g.

22. Networks State 3 topologies
Data collisions speed, reliability, adding extra workstations, cost.
Compare a star and ring topology.
State 3 advantages of a LAN compared to stand alone computers.
State 3 disadvantages of a LAN.
Draw and label the different topologies.

23. Packet Switching / routing
For transferring data on network.
Files are split into packets to be sent on network.
They may follow different routes (routing table) but eventually reach destination.
Then re-assembled and viewed.

24. Networks
Packets of data (Source address, destination address, data, checksum, how to reassemble, tracking info)

25. Protocols / rules Send/receive data
TCP/IP – Transmission Control, Internet Protocol
FTP – File Transfer
HTTP – Hypertext Transfer Protocol

26. Security Access Levels Passwords (strength, brute force attack)
Encryption
Acceptable Use Policy
Disaster Recovery
Backup
Archiving

27. File types / compression
Provide examples of the following file types:
Html
Jpeg
Mp3
Fla
Png
Lossy / Lossless compression

28. Programming Errors Provide examples of the following Truncation
Rounding
Logic
Syntax
Run time

29. Programming State two advantages of using libraries.
What is the difference between global and local variables?
What is a constant?

30. Libraries Already tested Quicker to enter code
Less code, easier to manage
Random numbers, time, etc.

31. Programming
State all outputs if the user enters 5: Output “Y9 Maths Data” Input X If X > 5 Then output “Pass” Else output “Fail” End if If X > 3 Then output “You do not need to resit” Else output “Resit required”

32. Software development environment - facilities
Editor
Compiler
Interpreter
Linker (for libraries)
Loader
Debugger
Trace
Variable watch
Break point
Memory inspector
Error diagnostics

33. Compilers & Interpreters
Convert high level code to machine code.
Interpreter – one line at a time, every time code is run.
Compiler – all lines are converted once, does not require conversion on next run, unless code amended.
Compilers
Lexical – comments and spaces removed
Syntax – syntax errors identified
Semantic – suitable data types for variables
Code generation – machine code generated.

34. Legislation Data Protection Act
Protects individuals who have details stored by various organisations.
Number of rules that must be followed.
State 3 rules of the DPA.
State 3 organisations that store data about individuals.
Computer Misuse Act
Hackers & Viruses
Copyright Act
Illegal downloads