Palm OS Programming, 2nd Edition

Designing the Conduit

A conduit is a desktop application made in a desktop development environment. It uses HotSync synchronization to connect the desktop to the handheld. Conduits are responsible for the transfer of data to and from the handheld and the desktop. The user views the data using some application (a spreadsheet, for example, for viewing expense report items). The conduit needs to make sure that this desktop application has the data it needs to handle processor-intensive tasks. Before looking at the design of the Sales application conduit, let’s examine this issue of off-loading processor-intensive tasks.

Processor-Intensive Tasks

Here is another design rule to remember: use the conduit to transfer the data, moving processor-intensive tasks onto the PC and off of the handheld. If you can’t move tasks, you should almost always get rid of them.

Palm devices are noted for being both fast and cheap—two of the key features that have made them so popular. One of the reasons they are cheap is they have little bitty processors that don’t have much horsepower. Your job as a good application designer is to avoid taxing the handheld’s processing abilities. Don’t turn it into a slow device—there are already plenty of those around. This means that you may end up making design decisions about your database that don’t make sense from a desktop database designer’s point of view, but do make sense when you take into account the desktop’s superior processing abilities. Here is an example. ...