servers & clients : 

The Server is where the web site files live. The web server software runs on the server machine, responding to client requests by sending files back to the client. The server also processes CGI requests, runs programs, and accesses databases.

• Server software runs on the server machine
• The web site files are on a hard disk attached to the server
• The server software formats and delivers each web page element based on HTTP requests
• Elements are delivered to many clients at the same time
• A "hit" indicates that one element (not a page!) was delivered (e.g. an image)
• A web page is composed of many elements, therefore each page accessed generates many hits
• Hits vs. page visits vs. site visits
• Web server performance issues
  • Number of elements served
  • Number of bytes server

The client is the computer where the web page is viewed. The browser software runs on the Client computer and sends requests to the Server computer. When the client receives files from the server, the Client assembles the web page and displays it.

• The web browser runs on the client
• The client requests elements from the server
• It receives and "parses" the elements delivered by the server
  • First reads the HTML
  • Formats the page, and displays the text
  • Gets additional elements (images, audio, etc.) specified in the HTML
  • Displays additional elements
• Manages the interactions with the user (e.g. forms, scrolling, image maps, etc.), minimizing the amount of work the server has to do
• Runs client-side software (JavaScript, Java, plug-ins)

• The HTML file, which describes the page layout, defines links to other web pages, and contains the text for the page
• Elements that come from the same server where the .HTML files is, or from a different server
  • Image files (.gif, .jpg, .png)
  • Audio files (.mp3, .au, .ram, .mov)
  • Other multimedia objects (QuickTime movies, Flash, Real, etc.)
• JavaScript

See this directory for an example: Sample Web Site

1. Always use PC formatted disks on both platforms. The Mac can read PC disks, but the PC cannot read Mac formatted disks.
2. Always use the correct 3 character file suffixes (e.g. .psd for Photoshop, .doc for Word, .htm or .html for Dreamweaver). This is critical. The PC won't know what to do with your files if you don't use the proper suffixes.
3. Have MacOS 8.1 or later installed on your Mac. Earlier MacOS versions can work with transferring files between the two systems in a very limited way (only 8 characters are supported in the filename).

For the web page file names, be sure you use "index.html" (or "index.htm") for your first web page. Using this special name will tell the server to display this page as the default page for any directory of html files. Other HTML files should have meaningful names such as products.html or drinks_snapple.html, rather than names such as page1.html. Name your files as if you are giving the web site to someone else who won't be able to ask you any questions, for example, you 6 months after the project is finished when you can't remember anything about it.

Web file naming rules:

• No spaces in the filenames
• Use all lowercase letters
• No special characters in the filenames: For example none of the following are acceptable in web filenames: "!~:&(,
• The files MUST have the proper suffix (.html, .gif, .jpg)
• Be consistent in your naming of files, for example use the same prefix in a series of files. Also, to ensure that the files alphabetize correctly, always "zero-pad" your filenames when they have numbers in them. In other words, if you have a series of files numbered 1-20, the first file should be something like myfile01.jpg, and the last file should be named myfile02.jpg.

And again, it's critical that you name your files correctly from the start. If you attempt to rename your files after you've created your site, you will, in all likelihood, break the links between your web pages.

all materials on this web site © copyright 2003, Philip van Allen