This manual serves two purposes, presented in two separate parts, to:
1. Detail the critical requirements for migrating OpenEdge® applications from the classic OpenEdge AppServer™ to the Progress® Application Server for OpenEdge (PAS for OpenEdge), and to provide guidance in that process.
2. Describe the basic ABL features available for building PAS for OpenEdge business applications and any ABL client applications that access them, as well as supporting elements for Open Clients.
Migration involves two major areas: migrating the ABL business application itself and its clients, and migrating application and server administration. Application migration requires few, if any, changes in ABL code, and clients might require an update to the code that connects them to the server. However, because of significant differences in server architecture between the classic AppServer and PAS for OpenEdge, some ABL features on the server, such as self-service database connections, need to be handled a little differently. Even so, your existing ABL code is likely to change very little, although you might add an external procedure or two to the server configuration
Most of the process of migration is in server and application installation, configuration, and general administration, because PAS for OpenEdge is not another version of the OpenEdge AppServer, but offers much of the same functionality as the classic AppServer, especially for Internet applications, in a full-featured Web server. As such, you will use few of the same tools to create and managed PAS for OpenEdge instances as you do for the classic AppServer.
ABL application development for PAS for OpenEdge is not unlike that for the classic AppServer. However, PAS for OpenEdge supports the classic AppServer's session models (referred to as application models on PAS for OpenEdge) in a different way, because every PAS for OE instance supports both the session-managed and session-free application models simultaneously. Ultimately, you continue to code ABL in much the same way as you did previously, but manage the configuration and administration of the server and its applications very differently.
For more information on the PAS for OpenEdge architecture and administration, see Progress Application Server for OpenEdge: Introducing PAS for OpenEdge and Progress Application Server for OpenEdge: Administration Guide.
