Handheld devices present unique obstacles to user interface
design. The standard approach is to simulate a PC environment
and apply it on a smaller scale. There are two major problems
with this approach. First, the usage model for handheld
devices is fundamentally different than that of PC's and laptops. Handheld
devices are accessed frequently for short bursts (e.g., checking
one's schedule or looking up a phone number), whereas PC's are
accessed infrequently for long sessions (e.g., creating spreadsheets
or writing memos). This results in different tradeoffs and
design decisions.
For example, it becomes critical to minimize the number of
steps to perform common functions. The second problem is
that PC designs are designed for 640 x 480 resolution. On
smaller screens, every pixel matters and control objects designed
for larger screens take up valuable real estate that could be
put to better use displaying information.
We have designed an operating system specifically for handheld
computers that addresses these issues. The presentation
focuses less on theory and more on the real-life application
of our design, covering the following topics

Lessons learned from early PDA software design
PalmPilot design goals and informal metrics used to measure
our success.
Special emphasis will be placed on addressing the conflicting
goals of minimizing the number of objects displayed for simplicity
vs. maximizing the number of objects for fast access.
PalmPilot design process