1. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Research Issues in CORBA What keeps CORBA people awake at Night! Peter de Jong

2. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Contents  CORBA Introduction  Issues  1. Language Heterogeneity  2. Components  3. Transports  4. Application Coordination  5. Reuse of Services  6. Interoperability  7. Interworking  8. Tracking Computation  9. Tracking Resources  10. Scale

3. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Software Bus

4. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 CORBA 2.0 Architecture ClientServer DII StubSkeleton DSI ORBORB ORBORB IIOP-RPC DCE-RPC RPC IDL Compiler Object Adapter Interface Repository Naming Trading Transactions Security Object Services

5. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 OMG IDL  C++ like  Mappings to multiple languages  C  C++  Java  Ada  SmallTalk  Cobol  ILU (Xerox Parc)  Common Lisp  Python  Basic types  long, unsigned long  short, unsigned short  long long, unsigned long long  fixed  float, double, long double  char, wchar  boolean  octet  any  Constructed types  union, enum, structure  sequence, string, array, wstring  exception

6. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 IDL Operations and Inheritance  Operation Attribute  Return value  Operation  Parameter direction  User exception

7. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 IIOP Transport IIOP Wire Format Object Reference (IOR) Object Reference (IOR) Java ORB C++ ORB Client ORB Server ORB Locator ORB Type (hint) Host:port Object_key

8. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Object References Client Server Object =

9. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Issue 1 - Language Heterogeneity  IDL to Java Mapping  Multiple Inheritance  Class slot - corba object class  Rest are interfaces  Out parameters  Holder classes  Any  Helper classes  Exceptions  java exceptions  Object Reference  Java class reference

10. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Binary Compatibility in Java Mapping

11. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Other Language Issues  Pseudo Code (Almost IDL)  Local Objects (ORB API's)  Native Language Constructs  Local By-Pass (inproc)  Direct to IDL  Java to IDL rather than IDL to Java  Objects by Value  Object state (Not described in IDL)  Migrating implementations  Scripting Languages  Language specification rather than IDL specification

12. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Issue 2 - Components  Component CORBA  Absorb Java Soft RMI into CORBA  Java to IDL mapping (OMG RFP)  Objects-by-Value (OMG Submissions being merged)  Distributed Garbage Collection  Migration of object implementation (Information in java serialization, not in IIOP)  Component RFP  Component identity  Properties  Interfaces for component-events  Introspection  Mapping to Java Beans  Related Object Services  IIOP Firewall (OMG RFP)  Scripting Language (OMG RFP)  Java Script  Object locality constrains (getting rid of PIDL)  Multiple interfaces

13. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Issue 3 - Transports  Type  RPC  Async Message  Streams  Multi-cast  Quality  Load Balance  Highly Available  Transactional  Secure  Real-time  Embedded

14. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 The Next IIOP?  IIOP 2.0? (Proposals by Bill Janssen, Xerox Parc)  Minimize information transfer via Caching  Efficient type negotiation  Port Mapper  Transfer Syntax changes (alignment, any)  MUX (http://www.w3.org.pub/Protocols/MUX)  Multiple protocols multiplexed over the same connection  IIOP, HTTP run over the socket built over protocol  128 sessions per TCP/IP connection  MUX handles fragmentation for all protocols  HTTP-NG (http://www.w3.org.pub//Protocols/HTTP-NG)  Possible future replacement for IIOP

15. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Issue 4 - Application Coordination

16. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Issue 5 - Reuse of Services

17. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Issue 6 - Interoperability/Portability  Interoperability (CORBA 2.0)  IIOP (Compliance point)  Transactions  Security  General Architecture  Kerberos (compliance point )  SSL  Portability  Pseudo Objects  Portable Object Adaptor  Language Mappings  Profiles and Conformance  Embedded ORBs  Research Problems  Implementations more detailed then specs  Revision Task Forces  Compliance tests written by XOPEN  Proposals for Semantic specifications  Balance between implementation freedom and conformance  Special purpose ORBs

18. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Issue 7 - Interworking

19. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Issue 8 - Tracking Computation  Distributed debugging  Distributed profiling  Distributed Administration  Bootstrap  Install and Configure  Object Locator, Persistent servers  CORBA object services servers - Naming, Event, Trading, Security, Transactions  Discover distributed executing objects  Monitor execution  Start, Stop, Modify object operation

20. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Issue 9 - Tracking Resources  Distributed Garbage Collection  Distributed Scheduling  Real-Time constraints  Parallel searching  Agents  Copy and transmission constraints  Killing  Error handling  At most once semantics  Network partitioning  Computation continuing in one partition  Error recovery in the other  Versioning

21. H Research Issues in CORBA Peter de Jong Hewlett-Packard Usenix 8/12/97 Issue 10 - Scale  Integration of all Services  Security, Transactions, Fault tolerant, Real-Time, Persistent storage, Messaging,...  One Object distributed system which does everything well  Massively Distributed Systems  Integrate with the organizational Applications  Track organizational change  Goal of Object Bus - Integration vs execution  Integration  Legacy applications, multiple - object models, standards, OS, languages  Execution  High performance, secure distributed computation