Web: Lecture 2b

Lecture 2b: Web Searching and Downloading

Find information on the web using addresses, navigational features of web sites, and various search tools and techniques.
Download and view Internet files of different data formats using browsers, FTP clients and archiving software.

Links can be put on text, pictures, or buttons.
Most web pages have some sort of navigation bar of text or picture links on the left or at the top or bottom.
Some Web sites (like this one) use frames to separate navigational pages from content pages.
Some Web pages have forms similar to paper fill-in forms that include buttons, menus, lists, text boxes, check boxes, radio buttons, etc.
Some sites have a site map or site outline which lists all pages.

If you know a web site address you can type it in the address box and go there directly.
- Many large web sites have their own local search engines to search internal databases.
Several tools quickly search multiple sites on the Internet:
- A subject guide or directory is a web site that organizes its content hierarchically by subject (topics and subtopics).
- A search engine searches the web for one or more keywords you type and displays a list of pages found.
- A meta-search site submits your search to more than one search engine.
- Using a human search service, you can hire a real person to perform your search for you.
Specialized search sites allow you to search for specific content, e.g:
- people names/addresses/phone numbers, multimedia, software, maps, library books, products, newsgroups, mailing lists
Scholarly databases give access to abstracts and full text of articles published in academic journals, newspapers and encyclopedias.

Keyword searching finds documents containing the word or words you are searching for.
Use more than one word to narrow the search if you get too many pages.
Use Boolean operators to refine your search.
- word1 AND word2 finds only pages with both terms. (The default for most search engines is AND.)
- word1 OR word2 finds pages with either term.
- word1 NOT word2 finds pages with word1 but without word2.
Use + to include a term in a search, - to exclude it (filter out unrelated pages you don't want).
- +word1 +word2 -word3 finds pages with word1 and word2 but without word3.
Use quotes to search for an exact phrase, e.g. "Uganda Martyrs University".
Wildcard searching allows specifying parts of words but not all search engines allow it.
Some search engines allow other search criteria such as file or media type, file name, size, modification date, etc.
Browsers have search settings or preferences to customize which sites to search for what types of content.

If you write a research paper and use a web page or site as a source, you must acknowledge it just like you do a book.
Resources can be cited using one of several style guides:
- American Psychological Association, Modern Language Association, Chicago Manual of Style
The citation format also depends on what is being referenced:
- individual work, part of a work, journal or newspaper article, other types of online communication

To download and open a file, it helps to know what kind of file it is.
- Files on the web include many types or formats.
- Common formats include text, picture, sound, movie, animation, archive, or program.
The file format is generally indicated by its extension.
- An extension contains a dot and one or more characters, e.g. .htm or .html. It follows the filename.
Why do most extensions have three letters? Which extensions are primarily used on certain operating systems?

Documents: .htm or .html or .shtml (formatted hypertext), .txt (plain text), .doc (Microsoft Word document), .pdf (Adobe Acrobat Portable Document Format), .rtf (Rich Text Format)
Image files: .gif (Graphics Interchange Format), .jpg or .jpeg (Joint Photographic Experts Group), .png (Portable Network Graphics), .bmp (Windows bitmap)
Audio files: .wav, .au, .snd, .aiff, .ra or .ram (Real Audio), .mid (MIDI), .mp3
Video files: .avi, .mov, .qt (QuickTime), .mpg or .mpeg (Motion Pictures Experts Group), .rm
Animation files: animated .gif (GIF89a), .swf (Shockwave Flash)
Archives: .zip (WinZip), .sit (StuffIt), .gz or .tar.gz or .tgz (GNU Zip)
Programs: .exe (executable), cgi-bin/ (Common Gateway Interface binary), .js (JavaScript), .class, .jar, .jsp (Java), .vbs (Visual Basic Script), .asp (Active Server Pages), .php (Apache's Hypertext Preprocessor), .cfml (ColdFusion), .pl (Perl)

To download a link to any type of file or a picture, right-click on it.
- You can then choose to open in a new window, save, copy, print, or view its properties.
- If you click certain types of files, you are asked if you would like to open or save the file.
- If you select save, you will be asked for a filename and folder where the file will be saved.
The time it takes to download is displayed and depends on several factors:
- the size of the downloaded file (1 MB = 1,000 KB = 1,000,000 bytes)
- the speed of the web server and your Internet connection (and possibly your processor speed and memory)
- the location of the source file and the traffic on the server and on the network between the source and destination

Many freeware or public domain programs can be downloaded and installed for free.
- You should pay for shareware if you continue using it after a trial period.
- After downloading, you normally install the program by double-clicking it.
- To run a program if it does not appear in a menu or icon, type its full path name in the shell or command prompt.
An archive is a collection of files, usually compressed to take less space.
- You may need special software to uncompress and extract files.
- Some archives are self-extracting; you extract files simply by double-clicking the archive.
- Some programs are distributed in archives and need to be extracted before installing or running.

File Transfer Protocol (FTP) is both a protocol and a type of software for transferring files.
- Most browsers in use today have built in FTP features, but separate FTP client software packages also exist.
Files are accessed from FTP servers much like web pages from web servers, except the URL begins with ftp:// instead of http://.
- FTP sites are becoming less popular because web pages and programming can provide equivalent or better service.
FTP is often used by computer professionals for downloading software and documentation.
- FTP can be used to upload (publish) a website you created to a web server.