The Internet Flashcards
How do search engines fill their database with sites?
Program called a web crawler which looks for new sites.
What is a meta tag?
A list of keywords the website owner has chosen and put in the header of the html document so the web crawlers know what the site contains.
What factors can increase your website ranking (aside from PageRank)?
Using searched for keywords in the title tag
Age of site
Last or frequency of updates
Number of keywords appearing in specific tags
Relevancy of domain name
What is the PageRank algorithm?
PR(A) = (1-d) + d( sum of PR(Tn)/C(Tn)) where PR(A) is the PageRank of the site, d is a damping factor (~0.85), C(Tn) is the number of links from site Tn to A.
What does URL stand for?
Uniform Resource Locator.
What is the purpose of a URL?
To show where the location of the required resource is on the internet (it is the web address).
What does DNS stand for?
Domain Name System.
What is the DNS?
They are designed to be easy to remember strings of text which point to the domain an internet resource resides in, for example .uk shows the resource is in the UK.
What is an IP address?
Internet Protocol (IP) address’s are the unique string of numbers assigned to a network/device, it shows where the data needs to be sent.
What is a WAN?
Wide Area Networks (WANs) are collections of LANs spanning more than a single location, the internet is an example of a WAN.
What is a LAN?
Local Area Networks (LANs) are several computing devices connected together on a single site.
Describe a bus topology.
All devices are connected to a central main cable which has the server at one end.
Describe a star topology.
All devices have their own dedicated connections to the central server.
Advantages and disadvantages of a bus topology?
Is cheaper as it requires less cable and dedicated hardware
Will fail if the main cable breaks
Is much slower with heavy traffic
Has lower security as PC’s can see all data on the cable
Advantages and disadvantages of a star topology?
Cable failures only affect one machine Fairly consistent performance Fast No chance of data collisions More secure Easy to add new devices May be very expensive If central server goes down the whole network is down.