IDG logo

Advertise with InfoWorld

SiteMap News Test Center Opinions Forums Careers Stock Quote Subject Indexes About Us Search Subscribe Home [Window Manager]

March 30, 1998

Two utilities help improve Explorer's use of data cache

Users of Microsoft Internet Explorer 3.0 and 4.0 are reporting problems with the browser that affect both its performance and its capability to perform functions such as Subscriptions to Web sites.

These problems relate to the way Internet Explorer handles its cache. A browser cache stores on your hard drive the text and graphics found on Web sites you visit. When you revisit those sites, viewing the same pages should be much faster because most or all of the information is cached.

Because a cache of any kind has a finite amount of disk space to work with, the oldest files in a cache are normally deleted first when room for newer files is needed.

Rather than deleting the oldest data first, however, Internet Explorer appears to delete cached data at random, according to David Pochron, president of Enigmatic Software. Pochron has written a utility, CacheMonitor, that allows Windows users to see how Explorer is managing (or mismanaging) its cache. You can also download CacheSentry from Pochron's site to manage Explorer's cache correctly.

Explorer's handling of its data cache seems to be a primary reason for problems with its Subscription feature. Subscriptions allow you to add a Web site to your list of Favorites, then "subscribe" for offline viewing. When you click Update All Subscriptions, the browser should download material that is new or changed on the Web sites you've selected. This allows you to peruse the material offline.

Users of Explorer 3.0 and 4.0, however, report that material they browsed only a few minutes earlier is sometimes no longer present in their cache and therefore cannot be viewed offline. Using CacheMonitor, it's possible to see what's happening. I watched in amazement as Explorer 4.0 intermittently deleted Web pages from its cache at random. Some had been read just 2 minutes earlier.

CacheSentry doesn't have a sophisticated setup routine yet, but if you can create shortcuts under Windows 95 or Windows NT, you can handle the installation of CacheSentry yourself, and I recommend you do.

First, download CacheMonitor.exe from It's a 39KB file that you should put into its own folder. Simply run it while using Explorer to browse the Web. CacheMonitor starts a windowed DOS session in which you can watch Explorer manage its cache. Lines that begin with "Bad Delete" show instances when Explorer is deleting files out of its cache randomly. You close CacheMonitor by clicking its window and pressing Ctrl+C.

CacheSentry is available at Download the .ZIP file and unzip the contents into the same folder as CacheMonitor. You must then run Explorer and click View, Options, General, Settings. Set Explorer to use the largest cache size possible. This ensures that Explorer won't ever manage the cache, so CacheSentry can.

Finally, right-drag CacheSentry.exe into your Startup group to create a shortcut to it that will run the program every time you start Windows. Run CacheSentry at this point, then right-click CacheSentry's icon in the System Tray to configure its settings once. You can then forget about it.

I'd like to thank Davis Straub, co-author with me of Windows 95 Secrets, for pointing out CacheSentry.

Brian Livingston is the co-author of several best-selling Windows books, including the most recent Windows 95 Secrets (IDG Books). Send comments to Unfortunately, he cannot answer individual questions.

Missed a column? Go back for more.

Copyright © 1998 InfoWorld Media Group Inc.


Copyright © 2002. InfoWorld Media Group, Inc. is a member of complies with the ASME guidelines with IDG extensions For New media.