Palm OS Programming, 2nd Edition

Expandable

Palm devices are simple, but are designed to be expandable. This was true from the very first Palm device to the current models. Let’s look at hardware and then software to see what this means.

Hardware Expandability

Palm devices come with very few types of built-in hardware features. While hardware features have changed over the last six years, this has been not so much an addition of features as an improvement of the existing ones. See Table 1-4.

Table 1-4. . Palm hardware features

Feature	Early units	Current units
ROM/Flash RAM	512K	2 MB
RAM	128K	8 MB
Screen type	Black and White	Grayscale and color
Infrared	No	Yes
Connection type	Serial	USB and serial

There are Palm OS devices that have bar code scanners, modems, MP3 players, and memory sticks; they are just not on every device. Likewise, you can buy modems, cell phone attachments, keyboards, and Global Positioning System (GPS) add-ons for a Palm handheld. From this, it is easy to see that Palm’s strategy is to have this minimal set of basic features and encourage licensees and other hardware device makers to offer optional device enhancements.

There has also been quite a bit of hardware differentiation for expandability among the Palm OS licensees: Handspring has their Springboard modules, Sony devices have MemoryStick expansion, Handera supports CompactFlash cards, and Palm’s m500 and m505 support MultiMedia cards and Secure Digital (SD) cards.

Software Expandability

Palm has used the same strategy ...