Web Me Wireless: Web Clipping and PQAs

Gimme a Clip o' That

An Introduction to Web Clipping and PQAs

While the Palm Pilot has had a variety of terminal and browser options to go along with its add-on modem, it was the bandwidth and display issues that went along with the integrated wireless service in the Palm VII that inspired 3Com and Palm Computing to develop Web Clipping.

The goal of Web Clipping is to minimize both display requirements (to fit on the Palm’s screen), and bandwidth usage. Although there’s always a lot of talk in the Web development world of keeping page load times low and keeping things zippy for users with slow connections, in this case, the need is more urgent. The base wireless plan for the Palm VII is $9.95/month, and this includes 50 KB (yes, that’s Kilobytes!) of transfer. Every additional KB costs the user $.30. Needless to say, if you’re forcing buckets of data down the user’s narrow wireless connection, you’re pulling money right out of their pockets - and they certainly won’t be using your Web services on their Palm VII again any time soon!

50 KB certainly doesn’t sound like much of a monthly transfer allowance on today’s Web, but remember, we’re not dealing with transferring Web pages, but rather Web Clippings (think of getting individual articles clipped out from the newspaper, rather than the whole Sunday Times). In order to minimize the amount of transfer, Palm Computing decided to use a completely different model for user/server transactions. Web Clipping uses a "query & response" model rather than the standard Web hyperlink system. In this system of "application partitioning," the query portion of the application is stored locally to the user, in what Palm calls a Palm Query Application, or PQA [also now known as a Web Clipping Application, or WCA - ed.]. The PQA is basically a mini-Web site, preinstalled on the User’s Palm VII. It’s usually a small form that transmits an even smaller amount of data to the remote Web server.

Typically, Web Clippings returned from the server are small, dynamically generated Web pages created by a CGI script in response to a user query. They can also be static pages on an Internet server. Size is of the essence here - Palm recommends that the query sent up to the server be kept down to about 40 bytes, and that the Web Clipping sent back is under 360 compressed bytes.