Network Computingwww.networkcomputing.com

I got to thinking recently, after another astronaut copy bombardment in some advertisement, that a rather interesting astronautism is, "do you copy?" Clearly, on the Internet or intranet--as well as in many other applications--we do copy. Over and over again.

Copy This, Web Browser Think about all the copy operations that actually occur "automagically" on the Internet. A Web browser makes a copy of each page presented and caches that onto your local disk. (Those hidden cookies that Web sites love to foist on you also end up on your personal disk, but that's really more like littering, don't you think?)

Yet, it still takes time after pressing the BACK button to actually get the page you just viewed. Going from a headline news page down to the detailed article and back up again takes much longer than it should (coming off my disk, anyway--I have only 1 MB assigned for RAM ca ching on my 16-MB machine.). Notice that it does go back to the network Web server just to check that things haven't changed. So, does it improve performance? Somewhat.

More significantly, local caching lowers the impact on the network, since it does not alwa ys require redownloading everything that was already moved over the network. It also lowers the burden on Web servers since users don't always have to send everything over and again for re-viewings.

What Else Can You Do? Unfortunately, this local browser cache turns out to be only marginally useful to the end user. If the PC is offline, you may not get to see those pages, even though they are (or were once) in the browser cache. They are definitely gone if you quit the browser. Nor do you have much control over what stays in the cache. It's just a first-in, first-out bucket. Why copy the stuff if you're not prepared to do something with it?

Many vendors have noticed this copy simplicity problem, and have lept into the intelligent co py void. Traveling Software, Forefront, ZooWorks and many others are offering control over the copied content. Many operate as local proxy servers so that you can still use your own favorite browser. The user can mark pages to keep local and view them later when disconnected. The user can schedule the system to check for changes on an automatic basis and pre-fetch those pages in the background. Some offer the ability to search an index of the local copy (sometimes without retaining the local copy at all). These are all laudable approaches to improving the user experience that also have a modest yet positive effect on performance.

But, let's face it. It's taking increasingly longer to download pages on the Internet. Part of this is the volume of users on each site--a problem only good Web-site management can address. Another part is the volume of the traffic on the network. Unfortunately, these user copy solutions aren't necessarily helping. Pages are still downloaded at least once and usually multiple ti mes by a user.

Some products even exacerbate the problem. Newer pre-fetching caching solutions like Peak Technologies' Net.Jet will predownload the pages referred to by the page you're looking at so they are already in your local cache before you've even visited th em, or even if you never visit them. (How good are those ad statistics now?) So, they are actually increasing the load on the server and network. Even as PointCast polling has been turned off by corporate firewall managers, some site managers will turn off Net.Jet client access.