Caching software speeds up the Web
IntroductionBandwidth on the Internet is a precious commodity, one that individuals as well as groups accessing the Web want to use as efficiently as possible. Two new products help by caching Web objects you’ve already downloaded. Connectix’s Surf Express Deluxe 1.5 and Maxum Development’s WebDoubler 1.0 have different audiences – Surf Express is for single users, whereas WebDoubler targets small groups of users – but both do a good job of speeding repeat accesses of Web pages. Cache the wave
Surf Express Deluxe comes on a CD that contains versions for Macs and Windows machines, and installation is quick and easy. When you reboot, the Surf Express extension intercepts Web requests from your browser and tries to satisfy them from the disk cache. You don’t need to configure Surf Express (although you can launch the Surf Express application to monitor the program’s performance); you simply launch your Web browser, and Surf Express replaces the browser’s existing caching mechanism with one that caches more data and retrieves it more quickly. You install WebDoubler (from a single floppy) on a Mac you’ve designated as a proxy server to other users on your network. You then configure the browsers of users whose Web requests you want to cache, so that they use the WebDoubler Mac as their proxy. Although caching is WebDoubler’s forte, the program is geared for other tasks as well; its plug-in–module architecture makes it readily extensible. In addition to HTTP-caching plug-ins, WebDoubler includes plug-ins for cache control, content filtering, and user authentication. And you can administer the program from any Web browser, making remote administration simple. Gnarly features
Surf Express lets you configure several important performance parameters. For example, you can specify the size of the largest file to cache, expiration times for DNS information, and a list of URLs that should always be cached or never be cached – for example, sites that change frequently, such as stock-reporting services. (WebDoubler lacks this fine control, although you can set the program’s “aggressiveness” level – how likely it is to cache a page that may change frequently – and it lets you distribute the cache over multiple hard disks for better performance.) Surf Express gives you a graphical display of performance, showing the percentage of your computer’s Web requests it’s retrieving from the cache (see ‘Surf Express statistics’). You can also search the cache for text strings. Surf Express includes a utility called SuperSonic Search that lets you invoke five popular search engines simultaneously and obtain a single report consolidating the results from all of them. But although SuperSonic Search is fast, it limits you to five predetermined search engines. This would have been a breakthrough a year ago, but Apple’s new multi-index search utility, Sherlock, far surpasses SuperSonic Search in features and ease of use. Whereas Surf Express boosts Internet performance for individual users, WebDoubler does that and also helps you administer a Web-security policy for an entire network; you can establish a database of users and privileges to provide customized caching and access controls. And WebDoubler uses the Platform for Internet Content Selection (PICS) to block end users from seeing inappropriate material. However, PICS filters access only to sites that have a previously determined rating or that contain a specific keyword, such as sex or xxx. This scheme isn’t nearly as reliable as using a professionally reviewed and updated list of prohibited sites. During testing, both products did a good job of caching pages and bringing them up quickly on subsequent accesses. The speedup can be truly remarkable if you’re running the cache software on a fast CPU – 20 to 40 times as fast over a modem as downloading the page from the Web. Accessing non-cached pages tended to be slightly but noticeably slower with WebDoubler than with Surf Express, but because the former caches data from multiple users, the likelihood of a cached hit is higher than with the single-user Surf Express. Moreover, enlarging the size of Surf Express’s cache beyond a certain point actually slowed overall throughput, whereas WebDoubler wanted as large a cache as possible.