O2S Components Framework Day 1, Session 1, Part 3 July 2006 Quanta JustPlay Seminar Justin Mazzola Paluska jmp@mit.edu

Acknowledgements The O2S Components Framework is mostly the work of the Hubert Pham so he should get all of the credit for its implementation. These slides are derived from Hubert's slides.

Contents Motivation Objective Approach Model

Motivation Planner: high level goal  plan O2S Component Framework: plan  actualize

Motivation Developing asynchronous, distributed software is (still) painful: slow performance adaptiveness is difficult stubs (distributed objects) hard to debug failures!

Motivation Traditional distributed applications: logic intertwined with implementation

Objective A distributed software component framework that optimizes for: Simplicity Construction API and Environment Debugging Adaptiveness Performance Platform and Language Independence

Approach

Approach

Approach

Approach Construct applications by instantiating distributed components and interconnecting them together: circuit diagram model Monitor and debug by processing serial messages from implementation

Approach Generic Components on a variety of platforms Data Streams using a variety of protocols

Approach Synchronous Simple Environment Adaptable Language and Platform Independent Asynchronous Parallel Low Performance Overhead

Approach: Example def setup_voice_rec(): voice_rec = system.lookup("Voice Recognizer", grammar = "voice_shell") event_queue = system.get_event_queue(handler = handle_event) voice_rec.set_recognition_target(event_queue) voice_rec_input = voice_rec.get_audio_sink() mic = hand_held_device.get_mic() system.connect(voice_rec_input, mic) def handle_event(new_event): if new_event.recognized_token == "Hello":

O2S Model Synchronous Simple Environment Adaptable Language and Platform Independent Asynchronous Parallel Low Performance Overhead

O2S Stack The O2S Stack establishes the Control Environment Properties: Many implementation technologies available for every layer Each layer depends only upon the abstractions established by the layer immediately beneath Can swap out any implementation for another

Transport Low level RPC and wire encoding for basic primitives. A Few Known Implementations: XML-RPC SOAP Sun RPC O2S uses off-the-shelf XML-RPC

Network Object Provides network object packaging; transparency in passing and receiving references to remote objects; data serialization and marshaling. Some Implementations: Sun Java RMI OMG Corba O2S NPOP

O2S NPOP Network Portable Object Packaging Language and Platform Independent Pass object references between methods, processes, and hosts Automatic Stub Generation Object Interning and Reference Tracking Named by a URI to an XML specification

O2S NPOP

System Management Provides “host-level” abstractions and services: health monitoring event messaging directory services for network object discovery

System Management A Few Implementations: Sun Jini (uses RMI); JXTA UPnP IETF Service Location Protocol O2S Architecture

O2S Architecture Entity host management runtime environment for remote objects Registry health monitoring + subscription/notification (bootstrap) directory services Event / Message Passing

O2S Architecture Health Notification Subscription

Component Structuring Provides a framework for constructing, interconnecting, bundling (abstracting), and hotswapping sets of distributed modules. Some Implementations: Weaves [Gorlick91] O2S Components In SVN HEAD, but not in the current snapshot

O2S Model Synchronous Simple Environment Adaptable Language and Platform Independent Asynchronous Parallel Low Performance Overhead

Implementation Environment Plaforms MS Windows GNU/Linux Apple OS X – PowerPC and x86 Devices HP iPAQ Nokia Mobile Phones GumStix

Implementation Environment Low-Level Networking Protocols TCP Sockets Bluetooth UDP Datagrams (SVN HEAD) RTP (Soon!)

Implementation Environment Languages Python Java, C External Interfaces X10 home automation Galaxy VR & Flite TTS SIP VoIP + Asterisk (Soon!) AOL Instant Messenger

Questions? Day 1, Session 1, Part 3 July 2006 Quanta JustPlay Seminar Justin Mazzola Paluska jmp@mit.edu