for channel definitions under CICS/ESA find matching channel attributes in MQSeries Distributed Queuing Guide, SC33-1139

define the channels using the CKMC CICS transaction.

Note: Make sure that you use the same queue names in your OS/390 related definitions which you used under VSE/ESA whenever possible. This will minimize application changes.

Operating MQSeries for VSE/ESA includes:

initializing the MQSeries system and shutting it down starting and stopping queues

opening, resetting and closing channels.

Monitoring offers functions to:

monitor channel and queue activities browse queues.

Operating and monitoring facilities are provided through the MQSeries menu under CICS for VSE/ESA.

For MQSeries for MVS/ESA similar functions are provided:

for system and queue definitions through MQSeries commands for message channels under CICS through the DQM panels.

There is no direct migration support. You will have to make sure your operational staff is trained to use the MQSeries for MVS/ESA facilities. You can set up some procedures to automate these tasks.

9.5.4 MQSeries-based Applications

Applications using MQSeries for VSE/ESA are coded in COBOL for VSE and run under CICS for VSE/ESA. They use the (MQSeries for VSE/ESA specific subset of) MQI.

The first two application migration steps are independent of MQSeries:

1.you have to migrate a program written in COBOL for VSE to OS/390. The best choice is to migrate the application to IBM COBOL for MVS & VM Release 2.

2.you have to migrate a program written to run under CICS for VSE/ESA to run under CICS/ESA.

For some details on these steps refer to the respective chapters in this book.

The next step is to consider the Message Queueing Interface (MQI). The effort required for this step should be small since on a high level the MQI is identical for all platforms.

You should use theMQSeries Application Programming Reference, SC33-1673. This book gives a full description of the MQSeries programming interface for MQSeries for MVS/ESA. You should check that the MQI elements you used in your VSE/ESA based applications are identical with the ones under OS/390.

Minor adaptations may be required.

As a final step you need to compile and link your applications under OS/390.

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IBM OS/390 manual MQSeries-based Applications

OS/390 specifications

IBM OS/390, a versatile operating system, was a cornerstone in enterprise environments and played a pivotal role in mainframe computing. Released in the mid-1990s, OS/390 combined the strengths of IBM's MVS (Multiple Virtual Storage) with new features and enhancements, targeting scalability, reliability, and performance in demanding business applications.

One of the key features of OS/390 was its robust support for multiple users and processes. The system allowed thousands of concurrent users to access applications and data, ensuring high availability and minimizing downtime—a critical requirement for many large organizations. This scalability was supported through various enhancements in memory management and processor scheduling, enabling optimal resource allocation across diverse workloads.

OS/390 was known for its superior workload management capabilities. The Workload Manager (WLM) component allowed administrators to define service policies, specifying how system resources would be allocated according to the priority of tasks. This ensured that critical business processes received the necessary resources while less critical tasks were managed more flexibly.

Another significant characteristic of OS/390 was its commitment to security. The operating system provided comprehensive security features, including user authentication, data encryption, and auditing capabilities. This focus on security was vital for organizations handling sensitive data, ensuring compliance with regulations and safeguarding against unauthorized access.

OS/390 also supported advanced technologies that facilitated integration and development. The system included features like the IBM CICS (Customer Information Control System) for transaction processing and IMS (Information Management System) for database management. These technologies allowed organizations to build robust, high-performance applications tailored to specific business needs.

The ease of network integration was another strength of OS/390. With the advent of the Internet and global connectivity, OS/390 systems could easily interface with various network protocols, enabling businesses to operate in a connected world. This inclusion paved the way for many organizations to expand their capabilities and offer new services, driving digital transformation.

In conclusion, IBM OS/390 represented a significant advancement in mainframe technology, combining scalability, security, and robust workload management. Its rich feature set and support for critical enterprise applications solidified its role as a vital component of many organizations' IT infrastructures, ensuring they could meet their operational challenges head-on while supporting future growth. As technology continues to evolve, the legacy of OS/390 remains influential in the realm of computing.