Mobile Operating Systems Lesson 03 PalmOS Part 1

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Mobile Operating Systems

Lesson 03

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PalmOS

• 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

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PalmOS Features

• 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

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PalmOS Features

• A file in format of a database

• IP-based network connectivity and WiFi (in later version only)

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PalmOS

• 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

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Polling for events at specific

intervals

• Each polled event─ sends interrupt signal • Handled by an event handler

• Functioning as maskable non-prioritized ISR

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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)

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PalmOS Hardware Support

• Compiles for a specific set of hardware, its performance is very finely tuned

• Optimized to support a very specific range of hardware, CPU, controller

chips, and smaller screens of Palm OS-based devices

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Display Screen Support

• Generally wide screen • 160 × 160 pixels

• Optimized layout of desktop programs displayed on screen

• 256 colour touch screen

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PalmOS Memory Support

• 16 MB memory

• 256 MB internal flash (non-volatile ROM) • 256 MB card consisting of flash memory

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PalmOS Memory Space Partitions

• Program memory dynamic heap─ for process stacks and global variables • Multiple storage heaps─ for data and

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PalmOS File Format

• Format of a database • Multiple records

• Information fields about the filename, attributes, and version of the database for the application

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PalmOS Connectivity

• IP-based network connectivity • WiFi (in later version only)

• Wireless communication protocols

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PalmOS APIs

• Simple APIs compared to Windows CE • Simple APIs for developing the GUIs ─

buttons, menus, scroll bar, dialogs, forms, and tables

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PalmOS Desktop and Desktop Programs

• Desktop for Windows and Mac both and other essential software

• SMS, Address, Card-Info, HotSync, To-Do-List, SMS, Security, Date

Book/Calendar, Calc, Welcome, and Clock

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PalmOS PIM

• Address book

• Data book for task-to-do and organization

• Memo pad

• SMTP (simple mail transfer protocol) email download

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PalmOS PIM

• Offline creation and sending of POP3 (post office protocol 3) email

• Internet browsing functions using Blazer (a browser for handhelds)

• Windows organizer

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PalmOS Query Development Platform

• Query development support

platformPalm query applications (PQA) written using HTML and ported at Palm device

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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

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PalmOS Ports

• Serial and infrared ports for

communication with mobile phones and external modems

• Synchroniszing a PC personal area

computer using HotSync after resolving the conflicts in different versions of files during data exchange

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Port Protocols

• IrDA or serial device

• System mounted on a cradle

• Connects to computerPCs through IR or serial port

• A cradle is an attachment on which the handheld device can rest near a PC and

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Device handling

• Assumed as a new flash drive of a PC

• HotSync facilitates drag and drop of files from device to PC and vice versa

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Cards

• MMC (multimedia card)

• SD (secure digital) memory card • SDIO (secure digital input/output)

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Third Party applications support

• Examplesgames

• Travel and flight planner • Calculator

• Graphic drawings

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Application layer in architectural

layers of PalmOS

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OS and hardware layer in

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Lowest level layer in OS

• Kernel

• Directly interfaces the assembler, firmware (software installed in the

hardware devices in the system), and hardware

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PalmOS 4.x

• Adds improved security

• Improved GUIs,VUIs, telephony libraries • Standard interfaces for access to the

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PalmOS 5.x

• Supports(i) a standardized API for high resolution screen

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PalmOS 5.x

(iii) instead of persistent battery-backed

RAM, a non-volatile file system using flash memory─ saves the files and data in case the battery charge is draining out

(iv) ARM, the processor─ providing efficient code and an energy-efficient architecture

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Advanced PalmOS Handheld

• Merged PDA and smart phones

• Feature to double as a hard drive using USB cable to PC

• Enables the drag and drop of files

between the Palm and PC in a manner similar to the drag and drop functions in

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Recent Developments

• Integration in Wndows CE

• A few Windows mobile handheld devices in use are Palm look-alikes

• But these do not deploy PalmOS platform but Windows CE

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PalmOS Deficiencies

1. Instead of multi-tasking, PalmOS provides for running a sub-application from within an application

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PalmOS Deficiencies

2. Not an ideal platform for running

multimedia applications because due to PalmOS is not for designing real-time systems

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PalmOS Deficiencies

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

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Summary

• PalmOS designed for highly efficient running of small productivity programs for devices with a few application tasks • No multiprocessing support

• Simple

• File record as database • HotSync

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End of Lesson 03 PalmOS─ Part 1