ObjectSpace Voyager(tm) Version 2.0 provides a number of significant changes compared to Version 1.0 and Version 2.0 beta releases. In addition to maintenance changes, feature additions, and performance improvements, there are significant syntax and behavioral changes. The Voyager Core Technology User Guide, available in .pdf format, and the on-line Voyager API Guide are the best sources for understanding the changes and enhancements made to Voyager Core Technology.

Several important new features in Voyager Core Technology 2.0 are listed below with the corresponding chapters in the Voyager Core Technology User Guide as indicated below:

• CORBA Integration. Chapter 12, CORBA.
• Dynamic Aggregation. Chapter 3, Dynamic Aggregation.
• Activation Framework. Chapter 9, Activation.
• igen and cgen. Appendix C, Utilities.

For a complete feature list and brief descriptions, please see Chapter 1, Overview in the Voyager Core Technology User Guide. Chapter 2, Basics provides an introduction to the basic features required to build a simple distributed application using Voyager. The remainder of the guide provides detailed information on using Voyager including an appendix with numerous examples.

Persistence
Voyager does not include any kind of persistent storage, since this is best left to database products. Instead, Voyager now includes an activation framework, described in Chapter 9, Activation, that allows objects to be automatically loaded on demand from any kind of database.

ObjectSpace plans to provide a Voyager 2.0 compatible version of VoyagerDb. VoyagerDb will be available free of charge on the ObjectSpace web site in early 4th quarter 1998.

Class Loading
Voyager still provides remote classloading capabilities, but it is no longer an automatic process. Classes are loaded from a remote class repository, they do not follow an object as it moves between Voyager hosts. Chapter 2, Basics, describes how to have Voyager both load classes from remote servers or directories, and/or serve classes to remote clients.

Events
The event mechanism is still available and is described in Chapter 5, Multicast and Publish/Subscribe, and Chapter 6, Mobility. Also note events that have been removed are replaced by the Console logging system allowing for a less intrusive debuging logging mechanism.

Proxy Generation
Proxy generation is now dynamic. The vcc utility has been removed and replaced by the igen utility. The igen utility and interface style programming, are described in Chapter 2, Basics.