Building Distributed
Applications
Using the Progress AppServer


Overview of the Progress AppServer

This chapter introduces the Progress AppServer, the core of the Progress n-tier computing solution, and provides an overview of its central concepts. The Progress AppServer is the mechanism that allows you to distribute a 4GL application across multiple machines in a network. It does this by providing separate Progress sessions that communicate by having one session (the client application session) establish a connection with an AppServer. The connected AppServer then allows the client application session to execute 4GL procedures in another Progress session running on the AppServer and to return any results to the client.

The Progress AppServer also allows you to establish connections from specially prepared non-Progress client (Open Client) applications that can then execute 4GL procedures on the AppServer using mechanisms native to their own programming environment.

The AppServer also allows you to configure and program it for different modes of operation. The supported operating modes provide different mixes of resource consumption and performance characteristics. Thus, one or another operating mode might better meet your overall performance requirements, depending on the application.

This chapter provides the information necessary for you to begin preparing distributed applications using both Progress clients and Open Clients, and describes the following topics:


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