Distributed Computing Session Notes

1) OpenDoc (Neil Katin - CI Labs)

• Overview
  • plug and play documents
  • Rich multipart
  • Architecture for making 'parts'
• Edit in place
  • parts written separately then combined
  • component part architecture
• Linking and Scripting
  • very high level concepts, save to a file, etc.
  • no one language will make everyone happy
  • common language for scripts to communicate w/parts
  • in order to run a python script, one needs an interpreter on your system (runned by OpenDoc shell)
• Six technologies
  • OpenDoc Doc Architecture
  • OLE interaoperability
  • OpenDoc Component Architecture
  • OSA (Automation)
  • Bento (How to store things on disk)
  • SOM (Corba implementations)
• Contrast with Visual Basic
  • OpenDoc + Scripting language + toolkit is simmilar
  • OpenDoc is a lower level framework by itself
• OMG
  • Submitted to Common Facilities Task force
  • competing with Fresco
  • Built on top of CORBA
• WordPerfect implementation is available via ftp
• Apple just release developer rel 2 (opendoc@apple.com)
• IBM OS/2 2 months behind, must buy developer package ($99)
• AIX port several months behind
• More info... contact CI labs info@cil.org

2) ILU (Bill Janssen - Xerox PARC)

• Full slides from here.

• Inter-Language Unifications
• Attempts to eliminate the differences between languages
• define interfaces bewteen libraries
• support over 100 languages supported
  • Smalltalk, C, C++, Modula-3, lisp Python, TCL
• you can write your own
• Like to be able to 'mix-and-match' languages
• want librariy use used in the same address space to be fast
• want to support CORBA
• Simple types
• Object Model supports methods only, no data slots
• asyncronous methods (send data, don't wait for reply)
• works with both comiled and interpreted languages
• uses multiple inheritence
• deal with heterogenaety rather than try to fight it
• ILU extends CORBA
• Been out for about a year (version 1.8 released Mar 95)
• Very open to suggestions for python implementation changes

3) CORBA (Saurabh Srivastava - SGI - Iteractive TV project)

• Extending Python to be an applications development environment
• for Interactive TV.
• The CPU and other resources at the setup-box is assumed limited
• 6 Meg of memory is typical for a consumer setup box
• Just launched a system in Orlando
• Just now at the point of being able to do 'killer applications'
• Chose Python for:
  • namespace scoping scales well
  • interoperability with C, C++
• Service Architecture
  • Client/Server
  • Each server is a single process on IRIX
  • clients can run on IRIX or the settop
  • name service provides a 'global' namespace at a well-known-port for client access
  • All servers advertize themselves using unique names
  • Two ways of supporting replicated services
  • Not TCP but reliable one-way messaging
  • IDL stubs manage transparency automatically
  • IDL stubs are C++ stubs not Python
  • The video channel is reserved and not transported over IP
• CORBA Interface
  • on settop box you have a python program running with a stub interface to the CORBA DII - looks like a python method call! Or you can go to IDL directly via the C++ stub (uglier)
  • Have plans to build a 'Mamba' (their name for python) authoring environment:
    • Debugger
    • Class Browser
    • Script editor
    • Timeline Editor
    • 3D Modeler
    • Properties Editor
    • Spatial Editor
    • Overview Editor
  • Also needed:
    • Project Management
    • Asset Management
    • Data driven templates
    • Rich set of transitions
    • support Set Tops of dirverse capabilites
    • Perview on IRIX i18n
  • Security is based on authentication via shared DES
  • secret key encryption
  • Status:
    • Nothing in the Authoring envirnment is finished
    • Extension modules IDL, etc, is finished
    • More work needs to be done on size (now big)

4) OLE (Jim Ahlstrom)

• Object Linking and Embedding
• Microsoft product - turn on your reality meter :-)
• A way for multiple applications to work together
• e.g. a Word processor and a spreadsheet
  • how do you deal with the spreadsheet from the WP?
  • this is about the only thing that's working today
• Container App
• Server App
• OLE 2.0 seems complicated
• Feature called inplace activation
  • When you pull in an app with OLE a new menu item
  • Hard with OLE, easy with something like NEXTSTEP that has late binding
• Feature called automation
• A way of 'pickling' data for transport between 'Object'
• They have a set of interfaces (like ObjC protocols)
• They have a ways of testing for interfacing
• 32-bit version is hot-off-the-press
• OLE also available for Microsoft Foundation Classes (better)
• Use OSF/DCE to (sort of) communicate across process boundries
• Doesn't work with CORBA or OpenDoc (booo hiss)
• Microsoft does not 'seem' interested in this technology
• OLE across a net is supported in Chiro (so OS change
• to this next version of NT will be necessary)
• DEC to provide the OLE to Corba linkage (3rd party)

5) Objects on the net (Guido van Rossum)

• Working on turning a python Class into a server
• Developed a class to represent the current directory using the platform independant features of the os module
• Next using MI the class becomes a server
• On the client side, we pickle everything while checking for exceptions, then sends the pickle over the socket, complete with possible exceptions
• exceptions can be meaningless if they're not found
• Wrote an application that syncronized two file systems
• Does md5 checksum and does not ship it if files are the same
• This could be done with ILU... maybe a bit slower