Computer Science
- Created by: AOconnor
- Created on: 13-05-18 20:24
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- Computer Science
- WiFi
- Compatible device must contain WiFi certified chip to connect to wireless LAN signal between 2.5-5GHz
- Frequency ranges are divided into channels so devices can run without interference and signal loss
- Encryption standards
- WEP
- Oldest and least secure
- Easily hacked
- WPA/WPA2
- Use modern encryption methods with secure password to protect WLAN access
- WEP
- Network Protocols (rules of data transmission)
- Ethernet
- Connects NICs, routers and switches
- Data link layer
- Can handle large amounts of data
- Connects NICs, routers and switches
- TCP/IP
- Allow computers on multiple networks to transmit and receive data packets
- Internet and Transport layers
- Allow computers on multiple networks to transmit and receive data packets
- HTTP
- Rules followed by web servers, clients and browsers which host/present websites based on client requests
- Application layer
- Rules followed by web servers, clients and browsers which host/present websites based on client requests
- HTTPS
- Encrypts communication between server and client (online banking)
- FTP
- Connects clients and servers to exchange files
- Used to upload files to web server
- Application layer
- Used to upload files to web server
- Connects clients and servers to exchange files
- POP
- Used to login and retrieve email messages from mail server
- All messages are downloaded to device
- Application layer
- Used to login and retrieve email messages from mail server
- IMAP
- Allows access to mail server but messages are not downloaded, only read
- Allows synchronised access
- SMTP
- Used to send email messages to mail server
- Application layer
- Used to send email messages to mail server
- Ethernet
- Layers
- Set of protocols with specific functions
- Advantage
- It is self-contained so different developers can concentrate on one aspect of the network
- Fragmentation and defragmentation
- Fragmentation
- Data saved onto system and deleted once processed
- When new data must be saved, new files are created
- Files may be larger than spaces left from deleted files
- Files split up
- Files may be larger than spaces left from deleted files
- When new data must be saved, new files are created
- Data saved onto system and deleted once processed
- Defragmentation
- Files on hard disk moved
- Empty spaces collected
- Files moved to be stored together
- Fewer accesses needed
- Files moved to be stored together
- Empty spaces collected
- Files on hard disk moved
- Fragmentation
- Open source vs Proprietary software
- Open source software
- Created to be shared openly online at no cost, with no limits on editing, copying or distribution
- Proprietary software
- Owned by individual or company
- Permission to use software is purchased through a license
- Software cannot be edited or shared in any way
- Owned by individual or company
- Open source software
- Legislation
- Data protection act
- Protects personal information held about individuals and organisations
- Computer misuse act
- Prevents hacking and the damage of computer systems
- Creative commons licensing
- Provides licenses that allow people to share, use and edit pieces of work depending on license given
- Public domain license means no restrictions
- Attribution license means original creator must be credited when work is used
- Attribution-non-commercial license means work can only be used for non-commercial purposes
- Provides licenses that allow people to share, use and edit pieces of work depending on license given
- Freedom of information act
- Provides public with right to access information held by central and local governments
- Copyright, designs and patents act
- Provides creators with right to control how their products are accessed and sold
- Data protection act
- WiFi
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