Detailed affinity analysis

Each of the above command scenarios is dealt with below. A description of how the use of the command appears in the Transaction Affinities Utility Reporter report is given, followed by an assessment of any affinity problem it causes. However, it would be helpful ®rst to expand on the structure of a CSP segmented application.

The default CICS transaction identi®er that CSP provides for applications is XSPS, although this is normally replaced by a unique transid for the application concerned. CSP transactions are de®ned so that the initial program is DCBINIT or DCBRINIT, the former for the ®rst segment (that is, the ®rst transaction in a pseudoconversation), the latter for subsequent segments. These two CSP programs ensure that the correct environment is built for the application, including loading of programs and tables and saving and restoring of state data. DCBINIT and DCBRINIT branch to other CSP programs, but these other programs are not known to CICS. This means the Transaction Affinities Utility Reporter report shows DCBINIT or DCBRINIT as the program containing the affinity command, but the command offset is the generic x'FFFFFFFF'. In fact, the CSP program that issues most EXEC CICS commands is DCBMODS.

It is very important to note that a single report transaction/program/offset entry can conceal several affinity commands. Although the Transaction Affinities Utility Detector has correctly logged, and deduced information from, all the commands, it is only the ®rst one encountered that is described in full in the report. So the Transaction Affinities Utility may report DCBINIT issuing only ENQUEUEs, but in reality DCBMODS is issuing both ENQUEUEs and DEQUEUEs. Similarly, the Transaction Affinities Utility may report that DCBINIT is issuing only WRITEQ TS commands, but in reality DCBMODS is issuing READQ TS and DELETEQ TS as well. (The Transaction Affinities Utility Scanner shows that this is indeed the case when it is run against the CSP/AE load library.)

Note that there is a unique generic offset for each different command type within an affinity group. The generic offset is zero minus the group/function code for the command. So, for example, ENQUEUEs appear with x'FFFFEDFC', and DEQUEUEs appear with x'FFFFEDFA'. This is also the case for other command types.

ENQUEUE/DEQUEUE

There is an EQ affinity group in the report for each table or application or map that is loaded. The resource used in each case starts with 'FZE' and contains the name of the load module concerned. Other resources that may appear are 'FZELOAD' and 'FZETUTRI'. The programs involved are DCBINIT and DCBRINIT.

Upon analysis, this use of ENQUEUE/DEQUEUE does not cause affinity. Here, the ENQUEUE/DEQUEUE is being used to serialize a browse on an ALF, so that another CSP application in the same CICS region does not interfere with the loading process. If multiple CICS regions were cloned, each cloned CICS region must perform this same loading process, but this has no effect on any of the other CICS regions. So the ENQUEUE/DEQUEUE is not CICSplex wide and does not cause affinity. All that is required is to ensure that each CICS has access to the ALFs. Because these are used read-only by CSP/AE, the ALFs may be shared without resorting to the overhead of function shipping.

Chapter 6. Running the Reporter 51

Page 67
Image 67
IBM OS manual Detailed affinity analysis, Enqueue/Dequeue

OS specifications

IBM OS, or IBM Operating System, refers to a family of operating systems developed by IBM to support its hardware architectures. IBM has produced a range of OS versions tailored for different computing needs, such as mainframes, servers, and personal computers. Among the most notable operating systems in IBM's portfolio are OS/2, z/OS, and AIX, representing a blend of innovation and reliability that has defined IBM's reputation in the computing world.

One of the defining features of IBM OS is its robust multitasking capabilities. Both z/OS, predominantly used in IBM's mainframe environments, and AIX, the Unix-based system for IBM Power Systems, support multiple users and processes simultaneously. This ability allows organizations to run numerous applications in parallel efficiently, maximizing resource utilization and improving productivity.

In terms of security, IBM OS incorporates advanced features aimed at protecting data and maintaining integrity. z/OS offers multifactor authentication, data encryption, and a security model that adheres to the latest regulatory requirements. AIX provides Secure Virtualization, which enhances isolation and security in cloud environments, essential for enterprises handling sensitive information.

Another key characteristic is the adaptability of IBM OS to modern technologies. For instance, z/OS is designed to integrate with cloud computing, open source, and DevOps practices. This adaptability supports organizations in modernizing their infrastructure while retaining the stability associated with IBM solutions. AIX similarly supports containerization and virtualization, which are critical for optimizing resource usage in dynamic computing environments.

IBM's commitment to scalability is evident across its OS offerings. Organizations leveraging z/OS can handle enormous workloads and transactional volumes, making it a preferred choice for industries like finance and telecommunications. AIX also supports scalability, allowing businesses to expand their computing resources as demands grow without significant downtime.

The availability of development tools and environments is another noteworthy aspect of IBM OS. With robust IDEs and programming languages support, developers can create and deploy applications smoothly. This assists businesses in streamlining their development processes and improving time-to-market for innovative solutions.

In summary, IBM OS encompasses a suite of operating systems characterized by multitasking, security, adaptability to modern technologies, scalability, and comprehensive development support. These features have cemented IBM's position as a leader in enterprise solutions, allowing organizations across various industries to thrive in an increasingly digital world.