Computer Science AS OCR
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1-1-structure-and-function-of-the-processor as5 主题
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1-2-types-of-processor as3 主题
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1-3-input-output-and-storage as2 主题
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2-1-systems-software as8 主题
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2-3-software-development as5 主题
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2-4-types-of-programming-language as4 主题
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3-1-compression-encryption-and-hashing as3 主题
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3-2-databases as3 主题
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3-3-networks as8 主题
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3-4-web-technologies as13 主题
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html as
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css as
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css-styling as
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javascript as
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variables-and-constants-in-javascript as
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outputs-in-javascript as
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selection-in-javascript- as
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for-loops-in-javascript- as
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while-loops-in-javascript- as
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strings-in-javascript- as
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operators-in-javascript- as
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nested-statements-in-javascript as
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functions-and-procedures-in-javascript as
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html as
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4-1-data-types as8 主题
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4-2-data-structures as4 主题
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4-3-boolean-algebra as1 主题
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5-1-computing-related-legislation as4 主题
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5-2-moral-and-ethical-issues as9 主题
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6-1-thinking-abstractly as3 主题
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6-2-thinking-ahead as1 主题
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6-3-thinking-procedurally as3 主题
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6-4-thinking-logically as2 主题
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6-5-thinking-concurrently as2 主题
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7-1-programming-techniques as9 主题
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8-1-standard-algorithms-and-big-o-notation as8 主题
lan-and-wan- as
Exam code:H046
LAN & WAN
What is a local area network (LAN)?
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LANs are networks that are contained within a small geographical location
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Typically, all the hardware used to make a LAN is owned by a single entity
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This makes them more secure than WANs, which have connections owned by third-party companies
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A LAN is a network that is built using hubs and/or switches that connect several devices
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It is common for one hub or switch to be connected to a router, which will allow the LAN to connect to other networks, such as the Internet
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A LAN can offer many advantages, such as:
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Centralised management – A LAN allows centralised management of updates, backups and software installations
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Security – A LAN can secure its devices with the use of firewalls, antivirus software and other security features to prevent unauthorised access
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File Sharing and collaboration – A LAN allows users on the network to share resources such as printers and other peripherals. Users of the network can also collaborate and share files and folders
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Disadvantages of a LAN include:
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If hardware fails, the network may not function properly or even at all
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Networks are more prone to attacks than standalone computers
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Access to data and peripherals can be slow depending on network traffic when compared to locally stored data and locally connected peripherals
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Maintenance – LAN networks require maintenance to ensure that software is up to date. Upgrades and backups can be costly
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What is a wide area network (WAN)?
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A wide area network (WAN) connects multiple local area networks (LANs) over a large geographical area
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A WAN allows users in different locations to share data and resources as if they were on the same network
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WANs usually use third-party connections such as leased lines, fibre, or satellite links
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These connections are provided by ISPs or telecommunications companies rather than owned by a single organisation
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For example, a company may connect its LANs in London and Manchester to create a WAN
Advantages of a WAN
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Enables communication and data sharing between offices or sites in different locations
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Allows access to central servers and shared databases from anywhere with a connection
Disadvantages of a WAN
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Typically slower than LANs due to greater transmission distances
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More expensive to set up and maintain because of leased lines or ISP costs
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More vulnerable to security risks as data travels across public networks
Worked Example
The internet can be considered an example of a WAN.
Describe what is meant by the term ‘WAN’.
2 marks
How to answer this question:
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For 2 marks, you need to make 2 points about what a WAN is
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Since the question uses WAN as an acronym, it is a good idea to show you know what WAN stands for
Answer:
Example answer that would get full marks:
A WAN (short for Wide Area Network) is a network spread over a large geographical area such as a country.
Worked Example
A coffee company has coffee shops located across the country. Each shop has its own Local Area Network (LAN)
The company wants to connect the shops in a Wide Area Network (WAN).
Describe two characteristics of a LAN.
2 marks
How to answer this question:
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You need to make 2 points about how a LAN is different from a WAN:
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LANs cover a small geographical area
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The hardware that makes up the LAN is typically owned by one company
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For this reason, a LAN is considered to be more secure than a WAN
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Answer:
Example answer that would get full marks:
LANs are considered more secure than WANs since the LAN’s connections are owned by the organisation that owns the LAN.
Responses