Version 9.6
 —  EntireX z/OS IMS RPC Server  —

Introduction to the IMS RPC Server

The EntireX z/OS IMS RPC Server allows standard RPC clients to communicate with RPC servers on the operating system z/OS running with IMS in BMP mode. It supports the programming languages COBOL, PL/I and C and can provide IMS-specific PCB pointers for access to IMS databases if needed.

This document covers the following topics:

IMS-specific PCB Pointers


The IMS RPC Server provides one worker thread. RPC requests are worked off inside the RPC server in the worker thread, which is controlled by a main thread. IMS-specific PCB pointers can be provided as parameters in the linkage section for COBOL and PL/I. They allow you to access the IMS PCB pointer IOPCB, for example to print data or to start an asynchronous transaction and to access IMS databases

IMS-specific PCB pointers are supported with the following programming languages:

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Inbuilt Services

IMS RPC Server provides several services for ease-of-use:

Extractor Service

The Extractor Service is a prerequisite for remote extractions with the IDL Extractor for COBOL and IDL Extractor for PL/I. See Extractor Service for more information.


Deployment Service

The Deployment Service allows you to deploy server mapping files (SVM files) interactively using the Deployment Wizard (see Server Mapping Deployment). On the RPC server side, the SVM files are stored in a VSAM file as the container. See Deployment Service for configuration information.


SMH Listener Service

With the SMH Listener Service you use the System Management Hub to monitor the RPC server. See Administering the EntireX RPC Servers using System Management Hub under UNIX | Windows.

The SMH Service is switched on if the parameter smhport is set. See parameter smhport under Configuring the RPC Server.


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The IMS RPC Server can be configured to execute the RPC request impersonated under the RPC client user ID. This means that for the request execution, the worker thread gets the identity of the RPC client. This is necessary when accessing (security) protected data sets, for example with the Extractor Service. The way authentication is carried out can be controlled by the RPC parameter impersonation.

The picture above shows the configuration impersonation=yes.

The lifetime of an impersonated task starts when an open request for an RPC conversation or a non-conversational RPC request is received. It ends when the RPC conversation stops (after a commit operation or timeout) or when the non-conversational RPC request has been performed.

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Usage of SVM Files

There are many situations where the IMS RPC Server requires a server mapping file to correctly support special COBOL syntax such as JUSTIFIED, SYNCHRONIZE and OCCURS DEPENDING ON clauses, LEVEL-88 fields, etc. the .

SVM files contain COBOL-specific mapping information that is not included in the IDL file and therefore not sent by an EntireX RPC client to the RPC server. See also When is an SVM File Required? under SVM Files.


The RPC server marshalls the data in a two-step process: the RPC request coming from the RPC client (Step 1) is completed with COBOL-specific mapping information taken from the SVM file (Step 2). In this way the COBOL server can be called as expected.

The SVM files are retrieved as a result of the IDL Extractor for COBOL extraction process and the COBOL Wrapper if a COBOL server is generated.

You can customize the usage of the SVM file using parameter svm. See Configuring the RPC Server.

SVM files are used for COBOL only.

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