NonStop Systems Introduction

NonStop Systems Introduction—527825-001
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The Application Server Environment
This section introduces the application servers used in most HP ZLE environments. To
provide a better understanding of these application servers, the discussion is
subdivided as follows:
•
Role of the Application Server outlines the role of the application server in the ZLE
environment.
•
Evolution of the Application Server Architecture traces the development of the
client/server architecture used by application servers, beginning with the earliest
models developed by HP and proceeding through the multi-tiered, distributed
object architectures used by most application servers today.
•
Application Server Functions explores some of the major client and server handling
functions performed by application servers.
•
The HP Application Servers presents a high-level overview of the three application
servers offered by HP: NonStop Tuxedo, NonStop CORBA, and the J2EE-
compliant BEA WebLogic Server.
Role of the Application Server
In the previous section, we discussed the role of Enterprise Application Integration
(EAI) in a ZLE environment. The application server is a central component of the HP
implementation of EAI; it provides a framework for developing and hosting all the
services, applications, facilities, and tools that constitute the EAI layer of a ZLE system.
Specifically, the application server provides a framework for:
•
Executing the programs that provide integration services for a corporation’s
business systems, enabling those systems to communicate and exchange data
•
Executing ZLE applications that update and retrieve information from the ZLE data
store
•
Developing new ZLE applications and services
•
Incorporating third-party applications and services into the ZLE framework
•
Enabling efficient communications between the business systems and ZLE
applications
Note. The term application server is used somewhat loosely in this section. The products
discussed in this section are not, strictly speaking, all application servers. The Pathway and
NonStop Tuxedo products are actually TP monitors, and the NonStop CORBA product is an
object request broker. BEA WebLogic Server is a true application server. But all these
products perform many of the functions generally associated with both TP monitors and
application servers, so for the sake of convenience, we refer to all of them as application
servers.