∙Reduce the size of a stand-alone dump. You can reduce the size of a stand-alone dump as you transfer it from tape to a direct access storage device (DASD) for IPCS processing.

31.3.2 Traces

There are a number of traces available in the OS/390 environment:

∙OS/390 System Trace. A low overhead trace that uses a System 390 architected instruction. The trace provides a summary of system processing and is normally running continuously. This trace is present in all dumps.

∙Master Trace. Provides a log of the most recently issued console messages at the time of a dump. This trace is formatted by IPCS when analyzing a SDUMP or stand-alone dump.

∙Component Trace. Shows processing within single OS/390 components and almost always used under the guidance of the IBM support center.

∙Generalized Trace Facility (GTF). OS/390 provides GTF to record trace data to DASD, tape or in storage. Many OS/390 components and subsystems write trace records to GTF with the most common being VTAM. GTF needs to be started in order for the trace records to be recorded. In addition the system programmer can issue SLIP commands to write trace records to GTF. GTF trace records can be formatted by IPCS, in addition VTAM trace records that are written to GTF can be formatted by ACFTAP.

31.3.3Analyzing Traces

Using IPCS you can format the entries of any trace in a dump or trace data set. You can also do the following with GTF and component trace records:

∙Selectively format records without deleting the unformatted data from the buffer or dump.

∙

∙

Find the system and time stamp for each record.

Mix formatted GTF and component trace records without combining the unformatted data.

∙

∙

∙

Reduce the number of records in a trace data set.

Extract trace buffers from dumps.

Combine GTF or component trace records into a single data set from multiple trace data sets.

31.3.4 Using IPCS

IPCS is a TSO command and is normally invoked while a system programmer is logged on to TSO, however in some cases it may be preferable to execute IPCS as a job through a batch invocation of TSO. Since the IPCS command must be executed before ISPF is invoked, there would normally be a separate logon procedure for users of IPCS.

An IPCS dump directory needs to be allocated for each IPCS user. Each dump directory can manage multiple dump data sets.

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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.
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