1. PalmOS

2. Palm OS • An OS for handheld devices
• Designed for highly efficient running of
small productivity programs for devices
with a few application tasks
• Offers high performance due to a special
feature that it supports only one process
which controls all computations by the
event handlers

3. • Single process (no multi-processing and
multi-threading)
• Compiled for a specific set of hardware,
performance very finely tuned
• Memory space partitioned into program
memory and multiple storage heaps for
data and applications

4. IP-based network connectivity and WiFi
Integration to cellular GSM/CDMA phone

5. • No multi-processing or multi-tasking • Simplifies the kernel of the OS─ there is an infinite waiting loop in the only process that kernel runs • The loop polls for an event

6. • Each polled event─ sends interrupt signal • Handled by an event handler • Functioning as non-maskable non- prioritized ISR

7. Example: Polling for the events
For a request to run an application or sub-application
For a search program request to process a query
Notifications (like time-out alarm)
GUI actions (such as touching or tapping the screen with stylus)

8. Display Screen Support
• Generally wide screen • 160 × 160 pixels • Optimized layout of desktop programs displayed on screen • 256 colour touch screen • Higher resolution support in new versions

9. PalmOS Memory Support 16 MB memory
256 MB internal flash (non-volatile ROM)
256 MB card consisting of flash memory which the user inserts into the device

10. PalmOS APIs Simple APIs compared to Windows CE
Simple APIs for developing the GUIs ─ buttons, menus, scroll bar, dialogs, forms, and tables
Using HTML markup language

11. PalmOS Desktop Programs
SMS, Address, Card-Info, HotSync, To- Do-List, SMS, Security, Date
Book/Calendar, Calc, Welcome, and
Clock

12. PalmOS PIM Address book Data book for task-to-do and organization
Memo pad
SMTP (simple mail transfer protocol)
download

13. PalmOS Client side Applications
GUI development support on C/C++ platform using Palm SDK
For Java application using J2ME and advanced tools, for example, Metrowerk CodeWarrior

14. Architectural layers of PalmOS

15. PalmOS Deficiencies
1. Instead of multi-tasking, PalmOS provides for running a sub-application from within an application
2. Not an ideal platform for running multimedia applications because due to PalmOS is not for designing real-time systems
3. Does not offer much expandability
4. Inability to adapt to different sorts of hardware may also be considered a limitation for this operating system