THD204 - TMA03 Part 2- World Wide Web Tools
To access information via World Wide Web you require an Internet account with an ISP (Internet Service Provider) who will usually provide you with all the required software. The software usually consists of a DUN (Dial Up Network - sets the PC to the necessary phone number for connection to the ISP and handles the dial-up procedure), a Browser and E-mail client software, which should auto-install on insertion of the CD into the CD drive. Once connected you fill in the necessary forms online and on completion your account is created.
Web Browser
A web browser is an application programme that provides a way to look at, and interact with, most of the information on the World Wide Web. A specialist FTP browser will be required for some operations i.e. uploading personal Web Pages. Web browsers use HTTP to make requests of Web Servers throughout the Internet on behalf of the user.
I currently use Internet Explorer, Netscape and Opera browsers, all of which run on Windows and there are versions that run on the Apple computer. You might ask why I use so many browsers when one will do, this is primarily because I have my own Web Site and I need to check whether pages are displayed correctly. Different browsers have subtle differences in how they handle web pages.
The browsers I use are broadly similar in operation and have some built-in support for multimedia applications, this can be increased by downloading "plugins", helper applications, which extend the browsers functionality i.e. Real Audio, Shockwave, Flash etc. The browsers themselves are typically WIMP (Windows, Icons, Menus and Pointers) applications requiring little keyboard input from the user, thus allowing access to the web with minimal keyboard skills. Navigation is carried out mainly by selection of hypertext links with the mouse, using a Search engine or by entering the web address into the browser. Some typing is required when specifying search criterion for a Search engine or entering an address into the browser i.e. www.microsoft.com most modern browsers will put the http:// in for the user giving http://www.microsoft.com.
The browser will also take a TCP/IP address such as http://193.89.100.90 though it is unlikely the user will know the TCP/IP address of a site, usually the user types in the URL (Uniform Resource Locator). The user's ISP will have a connection to a DNS (Domain Name System server) which looks up the typed URL and converts into Internet Protocol. The domain name is as useful and meaningful way of remembering an Internet address; www.microsoft.com is definitely easier than remembering a TCP/IP address, which has the form xxx.xxx.xxx.xxx where x represents a number.
Internet Explorer is currently provided free of charge by Microsoft in any version of their Windows software it is actually built in to Windows, part of the reason for the anti-trust case against Microsoft in the States. Some of its useful features include:
- Favourites - a 'bookmark' facility that allows the user to store addresses of frequently used sites for easy access.
- History - addresses of websites visited are stored for a time specified by the user.
- Search Engines - a selection of search engines to help finding of information on specified subjects.
- Other features that are user customisable are:
- Home page - sets the page to which the browser will point when going online.
- Settings for the size of the cache for webpages - Temporary Internet Directory size, and settings for the length of time History is to be kept.
- Content Advisor - restricts the content viewable.
- Internet Programs - set which programs are to be used for mail, HTML editing, etc.
- Advanced options - many customisable selections here e.g. making the browser open a new window or not for each link clicked.
- Another useful feature is the ability to make pages viewable offline thus cutting online time.
Search Engines
What is a search engine?
A search engine is an enormous index of the web pages available i.e. www.yahoo.com. The search engine itself usually consists of three parts:
- 1) A "spider" (also known as a "crawler" or a "bot") which goes and searches every WebPage that wishes to be searchable. To make a web page searchable the designer inserts HTML META tags in the start of the HTML code giving a description of content and keywords, the "spider" can then read this.
- 2) A program that creates the index from the "spider" results.
- 3) A program that receives the users search request then interrogates the index and returns the results to the user.
Actually there is a fourth way of getting your web page into the index and that is to submit it directly to the search engine, Yahoo employ people to look at and categorise web pages to their directory and some that are not deemed suitable are removed or not included.
Use of Search engines
The use of search engines allows information that would be difficult to find ploughing though books to be available very quickly. However the quality of the information could be suspect unless it can be verified as coming from a reputable source. The Internet is an open network so anybody can post information therefore casting doubt on its integrity. Using search engines can be extremely time-consuming due to the volume of information produced from the search criterion.
To use the search engine first you will have to go to its site i.e. www.yahoo.com, www.lycos.com etc. Once there type in you desired search criterion and click search, the search engine now searches its database for matches and then displays the results. There will probably be many thousands of hits this can then be reduced by modifying the search criterion and re-searching. Most search engines have advanced features that allow the use of Boolean operators in the search criterion that will help in significantly reducing the amount of "hits".
Security
Security is a major issue either for protection against viruses or against hackers. Whilst online a good virus-checker should be running to check downloads and e-mails for viruses. Protection against hackers can be gained by using a firewall; a freeware version is available from www.zonealarm.com.
When online banking or any form of e-commerce where personal details are to be entered e.g. credit card details should be completed though a secure server usually uses SSL (Secure Socket Layer). The e-commerce site itself should switch to SSL or similar security protocol when details are required, in Internet Explorer a closed padlock symbol is shown at the bottom right-hand side in the taskbar when connected to a secure server.
Skills Required
Some rudimentary knowledge of how to operate Windows is required. Minimal skills are required to access the Internet - interface is WIMP (Windows, Icons, Menus and Pointers) so minimal typing skills are required as navigation is achieved in the most part by clicking on hyperlinks.