method over the first would be the total flexibility available in creating the tape input to IEBUPDTE and the JCL necessary to execute this MVS utility. The advantage of the first method is its ease of implementation.

In order to write an ICCF procedure to create a ²SYSIN² format tape for the execution of IEBUPDTE, you will need to answer questions such as the following:

How much data will be moved on each execution of the procedure?

How large will the new PDS have to be to hold this data?

On what device type and volume serial will the PDS reside?

What will the data set name be for the new PDS?

What block size should be used on the new PDS?

The sample ICCF procedure which follows assumes that you will create a PDS corresponding to each ICCF library. It therefore unloads a single ICCF library each time it is invoked. When the procedure is executed you will be prompted for the ICCF library number you wish to unload, the TSO/E user ID, user-supplied name, and descriptive qualifier for the data set name of the new PDS, and the device type and volume serial on which the new PDS will reside. The block size for the new PDS will be 800 bytes, and 50 tracks with 10 directory blocks will be used to define the new PDS. The procedure creates an ICCF member named IEBUPDTE which is a DITTO card to tape job to be submitted to a batch partition for execution. The tape created by this job will be used on an MVS system to create a new PDS with the contents of the ICCF library.

Sample ICCF Procedure

************************************************************************

*

*This is an example of an ICCF procedure which could be used to

*create an MVS IEBUPDTE jobstream on tape which will create a PDS

*containing the members from an ICCF library.

*

*It creates an ICCF member named IEBUPDTE which is a DITTO card to

*tape job to be submitted to batch for execution.

*

************************************************************************

/LOAD DTSPROCS /OPTION SAVE RESET &&OPTIONS 00000000 &&LABEL TAG1

&&TYPE ENTER THE ICCF LIBRARY NUMBER YOU WISH TO UNLOAD &&READ &&PARAMS

&&IF &&PARAM1 EQ ′′&&GOTO -TAG1 &&SET &&VARBL1 &&PARAM1

&&SET &&VARBL2 &&USERID &&SET &&VARBL3 ′ LIB&&PARAM1′ &&SET &&VARBL4 ′ DATA′

&&TYPE ENTER THE TSO/E USER ID FOR THE PDS TO BE CREATED &&TYPE THE DEFAULT WILL BE &&VARBL2

&&READ &&PARAMS

&&IF &&PARAM1 EQ ′′ &&GOTO TAG2 &&SET &&VARBL2 &&PARAM1 &&LABEL TAG2

&&TYPE ENTER THE USER-SUPPLIED NAME FOR THE PDS TO BE CREATED &&TYPE THE DEFAULT WILL BE ICCF.&&VARBL3

&&READ &&PARAMS

164VSE to OS/390 Migration Workbook

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IBM OS/390 manual Sample Iccf Procedure

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.