Corba and Evolution

1
Corba and Evolution

• Announcements/Review
• Projects interfaces / interoperation today
• Upcoming lectures
• Planned Guest Lectures
• 3/4 Application Level Scheduling (Fran Berman) -
  Cancelled
• Well have a lecture on QoS enhancments of Corba
• 3/9 Netsolve (Henri Casanova)
• 3/11 Data Intensive Applications (Reagan Moore)
• Last Time
• COM and DCOM

2
Todays Outline

• Corba 2
• IDL, IIOP
• Additional Services
• Java/Corba Integration
• Object Web -- merging of the web and ORBs
• Interfaces/Interoperation

3
Beyond RPC gt Corba

• RPC enables
• Remote interaction with procedure call model
• Management of heterogeneity / interoperation
• Distributed Objects associate Data with the
  procedure calls
• Invocation on an object (with state)
• Procedure implementation defined by the object
  (polymorphism / object orientation)
• How do we make this work?
• At the start of the OMG (1991?), many diverse
  distributed object models.

4
Common Object Request Broker Architecture

• Define a standard set of interfaces
  (client-server)
• Define a standard IDL (data description)
• Define language bindings (C, C, Ada, Cobol,
  etc.)
• Enable the construction of orbs which would allow
  these things to interoperate
• gt these concepts are the core of the other
  systems weve discussed (ejb, dcom)

5
Corba 1.1 (1992)

• Basic ORB
• Basic Object Adapter (BOA)
• C bindings
• Naming
• Events
• Life cycle
• Persistence

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Generalize platform standardize, standardize,
standardize...

• Corba 2.0 (1995)
• IIOP
• C Bindings
• Transactions
• Concurrency
• Compound documents
• Security
• Time
• .

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Corba is a work in progress

• Corba 2.2 is standard now, 2.3 in the works,
  Corba Component spec in the works (several
  proposals)
• Messaging (MoM)
• POA (server portability)
• Java Beans, EJB, Objects-by-value
• Corba/DCOM
• Mobile Agents
• Automatice Persistence
• IIOP Firewall support
• Workflow
• Domain level frameworks

8
High Performance Distributed Computing

• Support for Quality of Service?
• Support for Real Time?
• Support for high performance?

9
Java/Corba Marriage

• Shotgun wedding pushed by the gang of four
• IBM, Netscape, Oracle, Sun
• Integrate Java Beans and Corba
• Enable integration of web and Corba, Object Web
• Product is Enterprise Java Beans (and the IIOP
  and Corba IDL integration present there)
• Who swallowed whom? Alignment vs. DCOM

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Motivation the Object Web

• Applet Model (present or past?)
• download, connect back to server
• launch server computations via CGI-BIN
• Problems
• slow launch, expensive
• how to get to other services?

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Object Web
http
iiop
corba

• Integrate http and iiop
• http -gt corba client
• active objects in web page, corba invocations for
  server interactions
• generalize security model
• entrée to multiple server interactions?

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Discussion

• What kinds of capabilities does this enable?
• What kinds of problems does it raise?
• Can you generalize this model to get beyond
  client server to multiparty?
• How does this relate to high performance
  distributed computing applications?

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Corba and Evolution

• Corba as a federation infrastructure for
  distributed objects
• Corba as a distributed platform (w/ many
  services)
• Corba merging with Java as a distributed platform

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Readings

• Today
• Object Management Group, Corba 2.2 Specification
  (available from www.omg.org)
• Orfali and Harkey, Client/Server Programming with
  Java and Corba, J. Wiley and Sons.
• Next Time
• Corbus http//www.bbn.com/products/dpom/dualuse.h
  tm