1. Palm OS CS 450 Section 3 Jason Kelske Matthew Jennings Stephen Jou Allan Topp Graham Kerster

2. Palm OS Most Popular OS for PDA’s Produced by Palm, Handspring, IBM, Sony, Samsung, some cell phones User Interface offers: –Ease of Use –Convenience Set the building blocks for the next era of mobile computing

3. OS Objectives Flexibility –Backward Compatibility 16 bit 32 bit –Platform Ease of Use –User Interface –I/O Mobility

4. Power Management Portability and Battery life Small and light weight – Easily accessible – Easy to carry around Battery – Uses minimal charge – Does not require huge batteries – Does not require a lot of batteries – Rechargeable

5. Power Management System Manager – Controls transitions between different power modes Three Modes – Sleep Mode – Doze Mode – Running Mode – Provides an API for controlling some aspects

6. Power Management Three Modes – Sleep Mode Power is off or after a time period with no user inputs Display and main clock shuts down Real time clock and interrupt generator continues to run Wake up upon an I/O interrupt Minimal battery usage – Doze Mode LCD remains on Displays the main clock Return to running mode upon I/O interrupt Some battery usage

7. Power Management –Running Mode CPU runs as long as it takes to process the users input Max battery usage

8. Data and File Management No Traditional File System –Data Stored in Chunks or Records in a Database Databases –Record –Resource

9. Memory Management Memory for Palm OS is on a removable card Card contains both ROM and RAM –Volatile vs. Non-Volatile Memory is divided up into “Heaps”

10. Memory Management (Image from kb.palmsource.com) Memory Partitioning

11. Memory Management (Image from kb.palmsource.com) Each heap includes: a header a master pointer table chunks a terminator

12. Memory Management Movable Chunks vs. Fixed Chunks Lock count Position on the Drive Heap Compaction

13. Process Management Single Process, event driven –Process must be single threaded Kernel can have multiple threads –Process runs until completion Kernel alerts can take control away from the process –When completed, OS switches to new process or to basic OS –Synchronization and deadlock not an issue among processes

14. Event Manager Translates I/O events from display to meaningful events for applications –Event Manager fires events to current application –Application runs in Event Loop until stopping event received –Application receives event and uses the appropriate handler

15. Conclusion Palm OS set the trend for most mobile communication 2 out of 3 PDA’s use Palm OS 85% of business’s include Palm OS in their handheld standards list Windows CE

16. Thank You ! Questions, Comments?