XPDNC - Suitable Solutions


About your Browser Cache


Cache is an area on your hard disk used for temporary storage of retrieved web pages. Browsers allow you to set aside the number of megabytes for cache use. When the cache is filled up, the browser starts to reuse previously accessed portions of the cache.

A web page is stored on the host server at a unique address. When the host server gets a request from your browser to send a particular page, the server simply transmits whatever the page author has set out at the supplied address. When the page author changes the page specifics stored at the unique address, the page is said to have changed.

When you ask your browser to display a page for the first time, you send a unique address to the host server. This unique address corresponds to the page you want. The page is retrieved from the host server and sent to your computer which stores it in its browser cache. Should you request this same page again, your browser checks its cache.

The browser will display the stored content it finds that corresponds to the page address you are again requesting. The browser looks to the cache to see if there is content available, and if so, the page you saw before is displayed. By first going to the cache, the browser can usually display the same page more quickly than retrieving the page from the host server a second time. Typically, when you click your browser Back button, the page presented is retrieved directly from the cache.

As stated above, many web pages change over time. For a single browser session the use of web page caching provides a smoother, quicker interaction with the Internet. However, there are some drawbacks. In particular, you may need to get the freshest copy of a page from the host server. With the page caching system, the browser will display the same content that it finds in its cache every time you ask for the page. To get the most recent content from the host server, you need a way to overcome the browser page caching feature temporarily.

Sometimes the Stop button is clicked before a page has been fully retrieved terminating the transmission in progress. Other times the page just doesn't fully load. In either case, the bottom of the page portion includes the message - Transfer interrupted! When you try to retrieve that same page at some later time, the browser could present the page portion up to the point of the terminated transmission that occurred previously. The browser is simply displaying the content within its cache that is available. You need to bypass the corrupted browser cache page and get the freshest page from the host server.

There is an added problem also. Consider the situation where your computer is hooked directly to the Internet. Whenever you tell your browser to get the freshest page available, the browser sends the request out to the host server, and the page is served up directly. Now think about the typical Internet hookup. There are Internet Service Provider (ISP) computers that are between your computer and the intended host server. These intervening computers have their own cache of pages. Often when you request a page from a host server, the page you get is a copy of the page stored by the ISP in its cache. In this way, the ISP can present the same content to many surfers without having to fetch the same content once for each request made. This is a great thing for content that never changes. But for content that changes over time, you need to be able to tell your browser to get the freshest page available from the host server.




Replacing cached pages 

Netscape uses Reload and Shift-Reload

Click the Reload button or use the top menu options View, Reload.

Netscape does attempt to display the most recent content it can find out about. If a fresh copy of the content is available, the browser requests this page from the host server. If this browser determines the content in your cache is current you will be presented with that copy.

Use Shift-Reload to request the page content from the host server.

Hold down the shift key and then click on the Reload button. This will cause the freshest page to be requested. Note: with a Mac, hold down the option key and click on Reload

Netscape retrieves a fresh version directly from the host server. This retrieval takes place regardless of whether the page has been updated or not. Using Shift-Reload instructs the browser to not consult cache for pages.


Explorer uses Reload

Click the Refresh button or use the top menu options View, Refresh.

The intent of the Refresh is for Explorer to replace the page stored in your browser cache with the updated page. Sometimes you may need to Refresh several times.


Emptying your cache

Sometimes the Reload / Refresh choices will not provide you with the most recent content because of internal cache directory problems. In these cases you will need to use your configuration options to empty the cache. This action basically tosses out the contents of the cache. Your computer may appear to run slower for the first little while after you flush the cache. Of course, this is because the browser must now contact the host server for each new page requested instead of grabbing it from the much faster local cache. But this symptom clears up quickly. Please consult the Help option of your browser to fully explain how to empty your cache.




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