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Lesson 2
Objective
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The Web server Describe the elements of a Web server. |
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In this lesson, we will review the basic elements of a Web server. You probably understand the nature of a Web server and will find
some of this information to be review.
Operating system
You have the choice of many different operating systems, such as:
Server files
A Web server commonly serves HTML and several image formats (GIF, JPEG, and PNG). It can also deliver program files of almost any
type, including Java, ActiveX, streaming video and audio, PDF, DOC, and TXT. The ability of a Web server to present files is a matter
of placing the proper files in the proper directories. The Web server can then present these files as long as the server recognizes
the format, or MIME type, of the media you place in the dirctory. Most Web servers have pre-defined MIME settings that allow the
server to handle the media you will use in your E-commerce server (e.g., HTML files, GIF and JPEG images, streaming media, and so
forth). However, it may be necessary to configure your server to handle a MIME type that it does not recognize.
HTTP
A Web server uses the Hypertext Transfer Protocol (HTTP). This protocol enables the Web server to receive requests and transmit
replies. E-commerce sites use many aspects of HTTP, including its ability to use cookies , to operate seamlessly with other
servers, and to work with databases.
Services and daemons
Generally, a Web server runs as a daemon process on UNIX machines and as a service on Windows NT machines.
CGI scripts
You can extend the features of a Web server through additional programs and servers. These programs are called common gateway
interface applications, or CGI scripts. You can also use proprietary solutions, such as Allaire Cold Fusion or Microsoft Active
Server Pages (ASP). Many server types exist. For example, you can use Real Player to provide streaming video and audio from your
site. Microsoft SQL Server, Oracle 8i, and IBM DB2, for example, allow a Web server to work with databases.
Client/server scripting
Web servers often deploy both client-side and server-side scripting. Client-side scripting includes the use of JavaScript and
VBScript. If you embed these scripting languages into an HTML page, you are engaging in client-side scripting. Server-side scripting
is the use of scripting languages to create programs that run on the Web server itself.
In the next lesson, the hardware factors affecting Web server performance will be described. |
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