Palm webOS by O'Reilly - Chapter 1 Summary - Part 2

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Palm webOS by O'Reilly - Chapter 1 Summary - Part 2
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Page 4 of 4

Section not required to build webOS apps - included for interest
webOS based on Linux 2.6 kernel
Combination of open source and Palm components providing user space services
referred to as Core OS
Access through Mojo and various services; no direct interaction with core OS
Users interact with apps and UI system manager which is responsible for the system UI
collectively known as Application Environment

App runtime envrionment managed by UI system manager
presents system UI manipulated by user
Framework provides access to UI widgets and Palm servivces
Environment supported by core OS environment: embedded Linux OS with custom sub-systems handling:
- telephony
- touch and keyboard input
- power management
- storage
- audio routing
All core OS capabilities managed by application environment and exposed:
- to end user as system UI
- to developer through Mojo APIs
App environment refers to System User Experience and feature set exposed to app developer, represented by Mojo Framework and Services
Core OS covers everything else:
- Linux kernel and drivers
- OS services
- Middleware
- Wireless subsystem
- Media subsystem
UI System Manager (UISysMgr) is responsible for almost everything visible to the user
App runtime provided by app manager:
- loads individual apps
- hosts built-in framework and some special system apps, status bar, launcher
- runs in a single process
- schedules and manages each running app
- handles all rendering through interfaces to Graphics sub-system and on-device storage through interfaces to SQLite
apps rely on framework for UI features and service access
UI features built into framework and handled by app manager directly
service requests routed over Palm Bus to appropriate service handler

Core OS based on version of Linux 2.6 kernel
standard driver architecture managed by udev with proprietary boot loader
Supports ext3 filesystem for internal (private) file partitions and fat32 for media file partition
media file partition can be externally mounted via USB
Wireless Comms system provides connection management that automatically attaches to WAN and WiFi networks when available
Switches conneections dynamically, prioritizes Wifi connections when both are available
EVDO or UTMS telephony and WAN data supported depending on device model.
webOS supports most standard Bluetooth profiles and provides simple pairing services
Bluetooth subsystem tightly integrated with audio routing to dynamically handle audio paths based on user perferences and peripheral availability
Media server based on gstreamer
includes support for:
- numerous audio and video codecs
- file and stream-based playback
- mainstream image formats
- image capture through built-in camera
video and audio capture not supported in initial webOS products but inherently supported by architecture

Includes tools, sample code, Mojo Framework, access to Palm Developer wiki with formal and informal training materials, tutorial and reference documentation
Registered developers also get direct technical support by email or hosted developer forum

Palm Developer Tools (PDT) installed from SDK and include targets for:
- Linux
- Windows (XP/Vista)
- Mac OS X
Tools enable you to:
- Create new Palm Project using sample code and framework defaults
- Search reference documentation
- Debug your app in webOS emulator or attached Palm device
- Publish an app
Tools include:
SDK bundle installer: Installs all webOS tools & SDK for 3rd party editors
Emulator: Desktop Emulator and Device Manager
Command-Line Tools:
- Create New Project
- Install & Launch in Desktop Emulator or Device
- Open Inspector/Debugger Window
- Package & Sign App
Tools can be installed as command-line on every platform; include bundles for integration into popular HTML editors and plug-ins for Eclipse and Aptana Studio.
Refer to Palm Developer Portal for most current list of supported editors and tool bundles

SDK installation includes copy of Framework and sample code
Don't need to include Mojo framework with app code because framework resident on device
Framework code included in SDK for reference purposes and debugging
Sample code includes samples for most significant framework functions including application lifecycle functions, UI widgets, each of the services.