Webserver

[Fact 1]: The response will describe the content of the file and contain the file itself.A Web server can be either implemented into the OS [[kernel will usually work faster, because, as part of the system, it can directly use all the hardware resources it needs, such as non-paged memory, CPU time-slices, network adapters, or buffers.Web servers that run in user-mode have to ask the system the permission to use more memory or more CPU resources.

[Fact 2]: The result is the local file system resource: /var/wwwThe Web server will then read the file, if it exists, and send a response to the client's Web browser.

[Fact 3]: Not only do these requests to the kernel take time, but they are not always satisfied because the system reserves resources for its own usage and has the responsibility to share hardware resources with all the other running applications.

[Fact 4]: As a consequence, the only way for a user-mode web server to match kernel-mode performance is to raise the quality of its code to much higher standards, similar to that of the code used in web servers that run in the kernel.

[Fact 5]: The resource is typically a real file on the server's secondary memory, but this is not necessarily the case and depends on how the web server is implemented.While the primary function is to serve content, a full implementation of HTTP also includes a way of receiving content from clients.

[Fact 6]: Also, applications cannot access the system's internal buffers, which causes useless buffer copies that create another handicap for user-mode web servers.

[Fact 7]: A is a computer program that delivers |style sheets]] and JavaScripts.A client, commonly a web browser or web crawler, initiates communication by making a request for a specific resource using HTTP and the server responds with the content of that resource, or an error message if unable to do so.

[Fact 8]: This is a significant issue under Windows, where the user-mode overhead is about six times greater than that under Linux.High performance kernel mode Web server for WindowsTo partially overcome above load limits and to prevent overload, most popular Web sites use common techniques like:

, by using:

to block unwanted traffic coming from bad IP sources or having bad patterns;

to drop, redirect or rewrite requests having bad HTTP patterns;

Bandwidth managementtraffic shapingWeb cacheLoad balancerRAM''', disks) to each computer;

tuning OS parameters for hardware capabilities and usage;

using more efficient computer programs for Web servers, etc.;

using other workarounds, especially if dynamic content is involved.

World Web Server Usage Statistics

RFC 2616, the Request for Comments document that defines the HTTP 1.1 protocol.

C64WEB.COM — Commodore 64 running as a Web server using Contiki.

[Fact 9]: This feature is used for submitting In 1989 Tim Berners-Lee proposed to his employer CERN a new project, which had the goal of easing the exchange of information between scientists by using a hypertext system.

[Fact 10]: As a result of the implementation of this project, in 1990 Berners-Lee wrote two programs:

a browser called WorldWideWeb;

the world's first web server, later known as CERN httpd, which ran on NeXTSTEP.Between 1991 and 1994 the simplicity and effectiveness of early technologies used to surf and exchange data through the World Wide Web helped to port them to many different operating systems and spread their use among lots of different social groups of people, first in scientific organizations, then in universities and finally in industry.In 1994 Tim Berners-Lee decided to constitute the World Wide Web Consortium .For a static request the URL path specified by the client is relative to the Web server's root directory.Consider the following URL as it would be requested by a client:http://www.example.com/path/file.htmlThe client's user agent will translate it into a connection to www.example.com with the following HTTP 1.1 request: GET /path/file.html HTTP/1.1Host: www.example.comThe Web server on www.example.com will append the given path to the path of its root directory.

[Fact 11]: On Unix machines, this is commonly /var/www.