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

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Palm OS CS 450 Section 3

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Palm os cs 450 section 3

Palm OSCS 450 Section 3

Jason Kelske

Matthew Jennings

Stephen Jou

Allan Topp

Graham Kerster


Palm os

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


Os objectives

OS Objectives

  • Flexibility

    • Backward Compatibility

      • 16 bit

      • 32 bit

    • Platform

  • Ease of Use

    • User Interface

    • I/O

  • Mobility


Power management

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


Power management1

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


Power management2

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


Power management3

Power Management

Running Mode

CPU runs as long as it takes to process the users input

Max battery usage


Data and file management

Data and File Management

  • No Traditional File System

    • Data Stored in Chunks or Records in a Database

  • Databases

    • Record

    • Resource


Memory management

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”


Memory management1

Memory Management

Memory Partitioning

(Image from kb.palmsource.com)


Memory management2

Memory Management

  • Each heap includes:

  • a header

  • a master pointer table

  • chunks

  • a terminator

(Image from kb.palmsource.com)


Memory management3

Memory Management

  • Movable Chunks vs. Fixed Chunks

    • Lock count

    • Position on the Drive

    • Heap Compaction


Process management

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


Event manager

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


Conclusion

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


Thank you

Thank You !

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