# 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