Friday, 19 April 2013

Unit 28 - P2 + P3

The functionality of a website can be affected by server and user side factors, the website may run slower if the user's computer has a poor processor, or if their internet connection and download speed are slow. The server side problems include the number of hits on the site and the capacity of the web server.

User Side Factors:
  • Download Speed - If the user has a slow download speed, the web page will take much longer to load and things such as videos or images may not load at all if the download speeds are too slow.
  • Browser - Different browsers may not always support certain file types used in website, such as flash videos, this can be fixed by either using a different browser, or downloading a flash player.
  • Cache Memory - The cache memory helps to load pages that are frequently visited more quickly, if a user visits a lot of pages very frequently, it is advisable to configure a higher cache memory capacity in the browser settings.
  • Processor Speed - If the user does not have a good processor, the web page will take longer to load and display content due to the amount of calculations made per second. A better processor would typically make website pages load quicker especially if they contain images and videos.

Server Side Factors:

  • Available Bandwidth - Bandwidth determines how much the user can download through their ISP, it is usually measured in seconds. A higher bandwidth means that the user can download more data in the same amount of time. Even if a user had high speed internet but low bandwidth they would still be restricted to a slow download speed.
  • Executions to be Performed before Page Load - Before the web page is fully loaded, certain aspects of the page must be loaded first; for example, the head, which hosts the CSS and JavaScript, and then the body and so forth. This is why a web page that loads slowly will only display the background and other colours at first, then the structure, followed by the body which holds information.
  • Number of Hits - The number of hits on a web page is the number of requests sent by a user's computer to the server hosting the web page. While it does not indicate the number of people visiting the site, it does give a rough estimate.
  • File Types - As mentioned earlier, certain browsers will not be able to display certain file formats, whilst problems with not being able to view images/videos/audio may be down to the browser of the user, it is also a server side factor as the web page creators have chosen to use those certain file types.

Data Protection Act:

This was designed to protect the personal information of living and identifiable people, anonymous data is not protected under the act. It only applies to information held on computers or a relevant filing system, including sales diaries and paper databases. The act states that any personal information that is held in a lawful manner must keep that information to themselves and may only use it for the purposes they require it for. 


Security Risks:
  • Hacking - Hacking is illegally gaining access to another computer for any reason, it is most commonly done to steal or delete certain data but can also be done for the purpose of downloading viruses onto the computer. Hacking involves re-programming the system so that it will perform functions that were not previously authorised by the owner.
  • Identity Theft - Stealing another person's personal information over the internet normally done by use of hacking or false websites; e.g. Bank Details, Name and Address, Phone Number etc. Identity theft over the internet is very common, as many people will happily enter their details into a form on the internet without checking that it is a secure site.
  • Viruses - Programs specially designed to corrupt or steal data from another computer, they are commonly disguised in files downloaded from the internet, or in email attachments, viruses compromise the security of a computer by performing actions such as shutting down anti-virus software and even stopping a computer from performing basic actions. A virus on a website can spread to the computer of everyone that uses the site, not just the computer hosting the website.

Security Protection Mechanisms:

There are several ways of protecting information on a website, these include; Firewalls, Strong Passwords and Secure Socket Layers (SSL).

  • Firewalls - A firewall is part of a network that is designed to prevent unauthorised access. It will permit or deny network transmissions based on set rules. There are two types of firewall, software and hardware. Hardware firewalls can be included as part of a router, software firewalls are programs that are on the computer, such as the Windows Firewall. Firewalls also help to prevent the spread of viruses, so if your computer is infected, there is far less chance that the virus can be transferred to other computers.
  • Passwords - Password strength defines how easy a password would be to work out, passwords containing a combination of randomised numbers and both lower and upper case letters will be the hardest to guess as there are far more combinations than just using one of the three.
  • SSL - The secure socket layer provides communications security over the internet, SSL encrypts the data of network connections above the transport layer and at a lower sub-layer of its application layer using a keyed message authentication code for message integrity. Websites with SSL will have a certificate to show that they are secure websites, this will make people far more likely to use the website. 
This is a screenshot of Tesco.com's Terms and Conditions.