Diagnosing System Problems, Dumps, Ipcs | IBM OS/390 specification

Chapter 31. Diagnosing System Problems

31.1 Problem Determination Tools

Several tools are available under OS/390 to help the system programmer diagnose problems. The majority of these tools are intended for system problems rather than application problems and are often activated under the guidance of the IBM or ISV support center.

31.2 Dumps

There are many different types of dumps available in OS/390 for various situations. SYSUDUMP and SYSABEND dumps are for application debugging and are generally formatted and written to a JES spool data set. These dumps are similar in function to that of a VSE dump obtained via an OPTION DUMP statement. SYSMDUMPS normally contain similar information for application debugging but are stored on DASD and formatted with IPCS. SDUMPS (often called SVC dumps) are used mostly by OS/390 and various subsystems and are written to a system dump data set and formatted by IPCS. Stand-alone dumps are taken when OS/390 no longer responds to commands from the operator console and has most likely entered a wait state or is in a loop. The system activity display (SAD) may be useful to help determine if the system is in a loop or wait state. A stand-alone dump is normally written to tape (or sometimes to disk) and later formatted with IPCS once OS/390 has been re-IPLed.

31.3 IPCS

The interactive Problem Control System (IPCS) is a tool provided in the OS/390 system to aid in diagnosing software failures. IPCS provides formatting and analysis support for dumps and traces produced by OS/390, other program products, and applications that run on OS/390.

31.3.1 Analyzing Dumps

When you submit unformatted dump data sets to IPCS, it simulates dynamic address translation (DAT) and other storage management functions to recreate the system environment at the time of the dump. IPCS reads the unformatted dump data and translates it into a more readable format. IPCS can identify the following:

∙

Jobs with error return codes Resource contention in the system Control block overlays.

IPCS also helps your own dump analysis. For example, you can:

∙Format control blocks. IPCS inserts field names into the output and displays the data in columns by field.

∙Browse unformatted dump storage. IPCS allows you to easily follow pointers to other locations in the dump. It also retains addresses of certain locations in the dump.

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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.

IBM OS/390 Diagnosing System Problems, Problem Determination Tools, Ipcs, Analyzing Dumps

Models: OS/390