Guide to Temporary Internet Files

What they are, why they are there and how you can configure them, brought to you - in perpetuity - by Kai Chandler

Anyone who has read my earlier series on PC Paranoia will be familiar with the trail that's left on your PC each time you go online.

Each page or image that you view may be stored in a folder on your hard disk as a Temporary Internet File. This folder is also called the cache. The files are stored to speed up future browsing. The theory is that if a file is called later, perhaps when you revisit the site, that file can be accessed more quickly from cache than webserver especially if you are using a slow modem link.

A good thing?

Surely anything that speeds up the internet is a good thing? Well, yes and no. While storing files in cache can speed your access to the Internet, there are a few downsides:

First, how can you be sure the file hasn't been updated since your last visit? If it has, you may not be viewing the current page.

Second, it takes time to sort through a large cache, especially on a slow system.

Third, all sorts of odd things can happen when browsing and some of them are caused by Temporary Internet files.

Practical PC top tip If you view a web page and think it may not be the current page, then you can force your browser to pull down the current page by selecting Control-F5 or hold down the Ctrl key while clicking the Refresh icon.

Finally, the cache can take up a significant proportion of your hard disk's space that would otherwise be free for programs and data.

The Temporary Internet files setup is controlled from Internet Options. You can find it by clicking the Start button, selecting Control Panel and then selecting the Internet Options icon. Another way is from Internet Explorer (IE) where it sits under the Tools menu.

There are several tabs in Internet Options. The one we want is called General and is the one that displays when you start Internet Options.

The section called Temporary Internet files contains three options.

Delete Cookies: Many websites leave a simple, harmless text file called a cookie on your PC- these are usually in the folder c:\windows\cookies. Cookies ensure that you are recognised next time you visit a site. Examples where they are used include sites that greet you by name, or tell you when you last logged onto their site. They are generally harmless but can be deleted. Note: the delete function applies to Internet Explorer 6 but not earlier versions.

Delete Files: This option deletes all your Temporary Internet files but leaves any cookies. It won't do any harm and may make your system slightly faster.

Settings: This option allows you to specify when to check for newer versions of stored pages, the location of the Temporary Internet files folder and how much space to allocate for Temporary Internet files.

The dilemma.

Should your system look for a file in the Temporary Internet files folder or download the file afresh? This is controlled by the most important setting: "Check for newer versions of stored pages." There are four options that determine when to check:

Every visit to the page: You'll always view the latest version - the browser checks the date of the file on the website and compares with what's in cache. If the current version is in cache, then that's what's displayed, otherwise it pulls down the current version from the webserver. This option is worth considering if you are using a fast ADSL connection where download time is not so significant.

Every time you start Internet Explorer: You'll always view the latest version when you first visit a site, but if that version is updated while you are online, IE will ignore it and continue to display the version in cache. However, if you are always online and have IE open in a session for a number of days and you revisit a page that you visited on a previous day then IE will cleverly pull down the latest version. This option is slightly faster than checking every visit.

Automatically: this is the default. It's actually the same as "Every time you start IE" but if a page is rarely updated, IE doesn't check every time.

Never: In this option, IE never checks so you always view what's in cache. This is quite dangerous as you may be viewing out of date information.

Where is your cache?

The location of your Temporary Internet files folder varies according to what version of Windows or Internet Explorer you have. Using IE6 and XP, it's in C:\Documents and Settings\default\Local Settings\Temporary Internet Files. The location is identified in Internet Options.

If you want to move the cache, perhaps to a faster drive, then the Move Folder function allows you to specify a new location.

How much disk space should you use for cache?

Some earlier versions of Windows allowed you to set a percentage of disk space but it's best to set a finite amount if possible. In the the screen image here it's set to 914MB. By default it's normally set to around 3% which with today's massive disk sizes, is probably way more than you'd need.

Can I see what's in cache?

If you want to see what's in your Temporary Internet files folder then just click on View Files or View Objects to list and view what's there.

What about privacy?

If you don't want other users to view your cache then you can ensure it's cleared at the end of each session. The option is on the Advanced tab of Internet Options. Scroll down to the security section and select "Empty Temporary Internet Files folder when browser is closed" There's more about this in the PC Paranoia series mentioned at the beginning of this article.

 

Kai Chandler reviews top tools for family friendly surfing at www.surfcontrols.com