Full HTML for

Basic foilset Overview of Tango Collaboratory

Given by Marek Podgorny at XII and DISA Meetings on January--March 98. Foils prepared 12 April 98
Outside Index Summary of Material

This presentation discusses Tango in context of an overall review of Collaboration Systems

Table of Contents for full HTML of Overview of Tango Collaboratory

 Denote Foils where Image Critical
Denote Foils where HTML is sufficient
1 TANGO Collaboratory - an Overview DISA XII Presentations January--March 98
2 Collaboratory systems: Taxonomy
3 Collaboratory systems: Taxonomy II
4 Collaboratory systems: Taxonomy III
5 Collaboration Transparency
6 Event Broadcasting: Criticism
7 TANGO Collaboratory
8 TANGO: Highlights
9 TANGO: Highlights II
10 TANGO: Control Application
11 TANGO: application control
12 TANGO Applications
13 TANGO: Status
14 TANGO/Wisdom
15 Video on Demand/TANGO Integration

Outside Index Summary of Material

HTML version of Basic Foils prepared 12 April 98

Foil 1 TANGO Collaboratory - an Overview DISA XII Presentations January--March 98

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
Marek Podgorny
NPAC, Syracuse University
HTML version of Basic Foils prepared 12 April 98

Foil 2 Collaboratory systems: Taxonomy

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
Basic architectures
  • Shared display: single instance of application, user input & display replicated via conference agent
    • Entire functionality of application is shared
    • Examples: Shared X (HP), NetMeeting (MS), ProShare (Intel), ShowMe (Sun), Timbuktu (Farallon)
    • Advantages: simple to implement
    • Disadvantages:
      • functional: simplistic, inflexible, awkward session control model, insecure (no data access control), no support for asynchronous collaboration, race condition problems
      • performance: generate heavy data traffic, unacceptable on WANs
      • incompatible with Web programming model assuming local intelligence
HTML version of Basic Foils prepared 12 April 98

Foil 3 Collaboratory systems: Taxonomy II

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
Basic architectures
  • Event broadcasting: each workstation runs its own copy of application.
    • (A) Virtual instance: all events shared (collaboration transparency)
    • (B) Independent data views: some events shared
    • Examples: Habanero (NCSA - B), Java Collab. Toolset (Old Dominion - A ), ProMondia (Univ. of Nuernberg - B), UARC (Univ. of Michigan - B), TANGO (NPAC - B)
    • Disadvantages: new category of SW, difficult to implement
    • Advantages: infinitely flexible and adaptable, generate little network traffic, perfectly fit Web/Java paradigm, can implement security, can support asynchronous collaboration....
HTML version of Basic Foils prepared 12 April 98

Foil 4 Collaboratory systems: Taxonomy III

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
Is chat server a collaboratory?
  • Chat servers multiply and offer 1D, 2D and even 3D interfaces:
    • Comic Chat (MS - 2D), Passport (BlackSun - 3D), Traveler (OnLive - 3D), The Palace (2D) .........
  • While technically similar, these products are geared towards creation of Gibsonian Cyberspace rather than towards a collaboratory
    • Collaboratory paradigm easily breaks when combined with orthodox cyberspace visualization paradigm
      • two avatars reading a Word document on a screen of the virtual computer rendered in VRML browser???
    • Conclusion: chat servers are not a collaboratory!
HTML version of Basic Foils prepared 12 April 98

Foil 5 Collaboration Transparency

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
Concept: design a system that allows using an application designed for a single individual to be used by a group of people without changing anything in the application
  • Shared display applications implement collaboration transparency
Proposed extension of the paradigm to the event broadcasting architectures (Old Dominions' JCT, Virginia Tech's JAMM)
  • technical approach: modification of the Java AWT to distribute events
  • our evaluation: we support event distribution model, but consider collaboration transparency an unrealistic limitation.
HTML version of Basic Foils prepared 12 April 98

Foil 6 Event Broadcasting: Criticism

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
Sharing possible only if applications deterministic
  • applications ARE deterministic or can be made so
Copies of applications must be present everywhere
  • but they are, being applets or downloaded via a push channel
Environments must be identical
  • Java VM takes care about this
Initial state of a newcomer impossible to define
  • not so for good OO design and object serialization mechanism
Cannot maintain consistency among copies
  • Difficult ? Impossible. Variety of sync mechanisms available
Web model enables event broadcasting!
HTML version of Basic Foils prepared 12 April 98

Foil 7 TANGO Collaboratory

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
TANGO is a software framework supporting computer-based communication and collaboration
  • Initial design and implementation for Command and Control under a DoD contract
  • Runs in Web environment and uses standard Web technologies
  • Allows for implementation of arbitrary collaboratory applications (examples will follow)
  • Multiplatform run-time and multi-language API
    • UNIX/Windows; Java (applet or application), C, C++, JavaScript, VRML2
HTML version of Basic Foils prepared 12 April 98

Foil 8 TANGO: Highlights

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
Technically, TANGO is a distributed system based on event broadcasting
  • TANGO does not assume collaborative transparency, although current design allows for it for certain applications
Core system is implemented in Java and as a browser plug-in
Base programming module is a Java applet
  • however, other forms supported as well, including Java, C/C++ applications, and JavaScript/VRML 2 modules
HTML version of Basic Foils prepared 12 April 98

Foil 9 TANGO: Highlights II

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
Global architecture is a mesh of servers
  • migration via hand-off mechanism (work in progress)
Session metaphor is a meeting room with tools
  • a more flexible "application session" model has been shown indigestible for early users
Asynchronous collaboration is (will be) enabled via session recording to database backend
TANGO modules can be downloaded from anywhere
  • can interact via a server at arbitrary location
HTML version of Basic Foils prepared 12 April 98

Foil 10 TANGO: Control Application

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
Application select
buttons
Application
Domains
Open/close and
floor control
Session
information
User information
HTML version of Basic Foils prepared 12 April 98

Foil 11 TANGO: application control

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
TANGO session, sync, and
floor control buttons built
into the application control
panel.
HTML version of Basic Foils prepared 12 April 98

Foil 12 TANGO Applications

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
Generic tools: chats (1D, 2D, 3D*), whiteboards (paint and draw)
Multimedia tools: audio/video conferencing, collaborative indexed streaming video
Shared browsers: slide shows, fully synchronized, shared JavaScript, customizable client-side apps
Virtual University: WebWisdom - interactive contents delivery system, a set of applets for physics curriculum
Domain specific applets: 2D and 3D (collaborative VRML) Visible Human, collaborative AutoCad*
*under development
HTML version of Basic Foils prepared 12 April 98

Foil 13 TANGO: Status

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
Core system implemented by a team of 3 programmers within ~6 months, available.
  • TANGO server for Unix and Windows NT
  • TANGO Plug-ins for Wndows95/NT, IRIX, Solaris
APIs for Java, C/C++, and JavaScript available
Two generations of GUI implemented
"Lessons learned" are being incorporated into TANGO II, scheduled for release in the Fall `97
  • new sessions paradigm, database support, multi-server support
HTML version of Basic Foils prepared 12 April 98

Foil 14 TANGO/Wisdom

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
Collaborative version of WebWisdom aimed at distance education
Uses the NPAC Collaborative System TANGO which has a well defined JavaScript API using LiveConnect for Java to JavaScript connectivity.
Supports asymmetric use with one multiframe WebWisdom ("master") controlling multiple clients running simpler single frame system.
With replicated course material, only control information is passed over the expensive network connection
HTML version of Basic Foils prepared 12 April 98

Foil 15 Video on Demand/TANGO Integration

From Overview of Tango Collaboratory XII and DISA Meetings -- January--March 98. *
Full HTML Index
Master-slave video client architecture
  • Master client for the teacher
    • has all capabilities of the stand-alone video client, including random access capability
    • uses unicast for server access
    • forwards video streams to a multicast address
  • Slave client for students/general audience
    • start/stop capability only
    • session control via TANGO session manager (more secure than standard MBONE)
No need for separate on-demand and broadcast video servers
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