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View Full Version : File cacheing and how a browser works.



Formula Jr
11-13-2005, 01:22 PM
When you first click on a web site, the first thing you computer receives is a relatively small text file. Its in a particular fomate call HTML. When you requested this file, your browser knew how to treat it because when you typed in the site name you added http:/ infront of the site name. In the body of this text file are commands to go find retrieve and display lots of graphical or audio files. These can be menus, buttons, gif animations, movies, sound and all the stuff that makes a page look pretty once the browser has assembled the entire set of resources specified in this small text file onto one page for display.
Realizing that the graphical content of web pages didn't change that much, people who wrote browsers figured out that you didn't have to download all this stuff every single time you requested and assembled a screen of the same site.
So they came up with file cacheing. What file cacheing does is save some of this graphical content on your harddrive. And then when you request that web site a second time, the browser checks to see if that file is on your harddrive first instead of trying to download it again. Its alot faster getting a file off your harddrive than through any internet connection.
For instance:
The Sponsor Banner is first loaded as a requested url off the net.
Its address is: http://www.donzi.net/leftmenu/lakeside_banner_adv.jpg

This is pulled off the Donzi board server and into your computer every single time if you don't request that your browser save it on your hard drive.
if it is cached on your hard drive it becomes just another JPG file that you computer has local access to. Same thing for the other graphical buttons on the left; club listing, advertising......etc, and the movie clip in the upper right hand corner.

You may have heard about ISPs that offer web accellerators. This is really the same as file cacheing.

Most browsers can be tweaked to save more of the repeated content of a web site.

I don't use IE, but if I rememeber its the same as Netscape 7.3 which I'll describe.

click: edit, advanced, cache and the cache menu will come up.
the default size is usually 50mb or so. I bumped that up to 250mb.
There are also selections of when or if you want to cache things, check for new stuff, when you request a page. You can say never, if something has changed, or all the time.

I set, if something changed.

I also set the link prefetching option on. This actively goes and looks for links in the html text and pre caches them, even if you haven't clicked through the button. It does this in the back ground while you are figuring out what you want to look at.

So when I hit donzi net off my bookmark list, most of the graphics involved with the page are loaded from my harddrive and not off the net. This speeds things up considerably.

anyway, hope I haven't confused any one.

bookmaster
11-14-2005, 10:35 AM
Owen, Thanks for taking the time to post that.