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# System prepended metadata

title: A-Level Computer Science 9608

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# A-Level Computer Science 9608

##  Chapter 1: Information representation

- Number systems
  - Denary Numbers
  - Binary Numbers
  - Hexadecimal numbers
  - Nibble
  - Conversion between them

- Number and quantities
  - Decimal prefix: kilo, mega, giga, tera (10^{3x})
  - Binary prefix : kibi, mebi, gibi, tebi (2^{10x})

- Internal Coding of numbers
  - Value range and byte used
  - One’s complement vs Two's complement
  - Binary arithmetic
  - Overflow
  - Binary coded decimal

- Internal coding of text
  - US ASCII vs ISO Latin-1
  - Unicode

- Images
  - Vector graphics, drawing object, drawing List, property
  - Bitmaps, pixel
  - Colour depth
  - Bit depth and RGB colour scheme
  - Image resolution vs screen resolution
  - File header
  - Difference usage of vector graphics and bitmap

- Sound
  - Band-limiting filter & Analog Digital Converter
  - Sampling rate & sampling resolution

- Compression
  - Lossless
  - Lousy

## Chapter 2 : Communication and networking technologies

- The evolution of the purpose and benefits of networking
    - Wide area network (WAN)
    - Local area network (LAN)
    - Difference between LAN and WAN
        - location
        - medium
        - ownership
    - The benefits of connecting PCs in a LAN
    - Internet advancement
    - The client-server model
        - thin vs thick client
    - File sharing
- Network Topologies
    - requirements for a data communications system :
        1. sender
        2. receiver
        3. transmission medium
            - air vs cable
            - simplex vs half duplex vs full duplex
        4. message
            - broadcast vs multicast vs unicast
        6. protocol
    - point-to-point
    - bus topology
    - mesh topology
    - star topology
    - hybrid network
- Transmission media
    - Cable : Twisted pair vs Coaxial vs Fibre-optic
    - Wireless : Radio vs Microwave vs Infrared
- LAN Hardware
    - Wired LAN
        - repeater
        - bridge
        - Network Interface Card (NIC)
        - hub
        - switch
    - Wireless LAN
        - use radio frequency
        - Wireless Access Point (WAP)
        - Wireless Network Interface Card (WNIC)
- Ethernet
- The Internet Infrastructure
    - Internet Service Provider
        - access ISP, regional ISP, backbone ISP
    - Router
    - Public switched telephone network (PSTN)
    - Cell phone network
- Applications that make use of the Internet
    - The World Wide Web (WWW)
    - Cloud computing
        - private cloud vs public cloud
    - Bit Streaming
- IP addressing
- Domain names
    - root servers, primary servers, secondary servers
    - top level domain, domain name, subdomain
    - name resolution
