Since Version 4.5, the functionality provided by the VisualAge Smalltalk Distributed feature has been provided by the Server Smalltalk (SST) framework. This section helps you migrate applications made with the Distributed feature to the SST feature.

Where the Distributed and SST features provide a comparable level of functionality, they part dramatically in their implementations and APIs. This section lists the major functions and APIs used by Distributed feature applications and states the equivalent functions and APIs of SST.

To migrate your Distributed code from a Version 4.02 or earlier product, in some cases you will simply need to replace one API method with another. In other cases, you will need to make more dramatic changes to your application to accomplish the migration. The level of migration will vary significantly, depending on the application and the Distributed feature functions and API that are used. If an application merely references a few well-know global objects, the migration costs will be low. On the other hand, if the application uses some of the advanced Distributed Feature functions, such as the Distributed Load or the Parallel Processing API, then the migration will take more effort.

This section touches on the major functions of the Distributed feature, though it does not cover all of the functionality of SST. SST is only described where it overlaps with the Distributed feature. For example, SST allows many different configurations to control its behavior. For this section, only the SST configuration that matches the Distributed feature is covered. This configuration includes by-reference marshaling, full import or export of object spaces, and logical process dispatching. Other functions of SST that are not available in the Distributed feature, such as the Java RMI support, are not covered in this section. Further, the descriptions provided here are for the purposes of understanding how to migrate your code. The descriptions are not meant to fully cover the Distributed feature or SST. In other words, consult the appropriate VA Smalltalk guide for more information.

This section covers the major functions of the Distributed feature in three sections: