Job Scheduling: JCL Emulation Products
In the conclusion of our three-part series, we examine JCL emulation products and review the status of job scheduling products for the Windows platform.
by Mike Gilbert
This is the last in our three-part series, that compares mainframe-based and distributed-based job schedulers and assesses the readiness of Microsoft Windows-based job scheduling technology to manage workloads at the enterprise level.
The first part offered a brief outline of the evolution of workload automation technology. Last week we provided an analysis of job scheduling capabilities on both mainframes and distributed platforms based on detailed comparisons of a selection of products targeting these platforms This week we conclude the series with a look at JCL emulation products and a summary of the status of job scheduling products for the Windows platform.
JCL on Windows
There is renewed industry interest in migrating traditional mainframe workloads to distributed platforms with system software which provides a compatible operating environment for IBM mainframe applications. JCL, the job scripting language of IBM mainframes, is used for jobs that are to be run under the control of a scheduler or one of the Job Entry Subsystems (JES2 or JES3) provided by IBM. JCL provides the detailed definitions of job steps, dataset definitions, output spooling, and program execution. If you are not preserving the JCL during a migration project, you will use the native scripting environment provided by the platform to define the details of the processes to be run. JCL emulators help make the transition to distributed platforms smooth. Fujitsu Software expanded its COBOL migration products in April 2006 with its release of NeoBatch, which supports JCL execution on the Windows platform. Micro Focus has addressed COBOL migration and support for JCL on distributed platforms with the Micro Focus Server for Mainframe Migration. Both Fujitsu and Micro Focus provide integration with job schedulers.
Both Fujitsu and Micro Focus provide a simple batch command-line interface that provides support for any job scheduler to start JCL processes and either wait for a completion code or cancel the job. Fujitsu can translate JCL into Jscript so users can extend their jobs to take advantage of Windows .NET features. Micro Focus supports CA dSeries Workload Automation with additional capabilities such as variable substitution, remote execution, asynchronous operations, and the ability to start and stop service classes or the entire JCL subsystem.
JCL Statement Support
Both vendors support the full JCL statement syntax, but execution support is limited to job processing statements. In general, this stance provides an acceptable solution, because the JES2 and JES3 control statements are either irrelevant in the new environment or superseded by facilities provided by the job scheduler. CNTL, ENDCNTL, OUTPUT, and XMIT JCL statements are not fully supported by these two JCL emulators. .
The JCL execution support provided by Fujitsu and Micro Focus is equivalent to JES2. This includes support for features such as service classes, PDS (Partitioned Data Set) file naming, GDG (Generation Data Group) file versions, remote job entry, output spooling, and tracing. These tools do not provide full support for checkpoint restart or advanced features such as SMS managed data, integration with other JES engines, or workload balancing.
Common Utility Programs
The IBM z/OS operating system ships with several important data management and utility programs frequently used in job steps to prepare data for processing by the application program.
The most important of these programs is the DFSORT utility, which is used to sort records in a sequential file. Both JCL emulators include IBM-compatible SORT programs, and both provide equivalents to the most commonly used utility programs.
The Job Scheduling Market
Job scheduling is a vibrant market, and job scheduling tools are likely to be found at the heart of enterprises large and small, regardless of their core platforms. Job scheduling has found a new purpose: providing a relatively simple and agile way to stitch together the myriad of applications and platforms required to automate new business processes in real time. Whereas early job scheduling was necessary to optimize costly IT equipment use, it is now used to optimize critical business processes and to manage service-level agreements.
Our original report (see note 1) set out to assess the impact of moving scheduling operations from a mainframe to the Windows platform. Here are the major conclusions drawn from this research:
- Organizations use job scheduling tools on Windows for real-time process integration more often than for traditional batch processing. Internet applications, regulatory compliance, and multiplatform administration are driving the need for process automation in organizations that have spread their workloads across many Windows or other distributed platforms.
- Organizations that operate heavy and complex workloads on the mainframe are more likely to operate traditional batch processing environments to optimize use of mainframe resources.
- Only three vendors offer mainframe-based job schedulers. These vendors compete in a stable market of 8,000 to 9,000 mainframe customers. At least 13 vendors offer Windows-based job schedulers and compete in the growing Windows Server market. An estimated 7,000 to 10,000 organizations already use distributed-based job schedulers.
- Job scheduling technology for the Windows platform is as mature as job scheduling technology for the mainframe platform, and it is equally capable of handling enterprise-scale workloads. The principle differences arise from the use of native platform features such as JCL.
- Both mainframe- and Windows-based job schedulers have strong support for integrating workloads across many applications and platforms, including leading packaged applications. Both have sophisticated failover and checkpoint/restart mechanisms to recover from system failures. Similar features are available on both platforms for workload balancing, planning and forecasting, calendar and workflow schedules, critical-process monitoring, and many other features.
- Windows-based job schedulers have stronger support for event-based automation, a greater number of graphical tools, and integrated support for new application workloads that are based on Web technologies (primarily Java, .NET, and Web services).
- Two vendors offer early-market products that support both mainframe COBOL applications and JCL migrated to the Windows platform. These products provide a basis for low-cost workload migration where preservation of existing investment is a priority. Both vendors provide the ability to integrate with third-party job schedulers to provide advanced scheduling capabilities beyond JCL.
If you are considering moving workloads to the Windows platform, you have a broad choice of job scheduling tools that can take on the tasks of workload management and automation. These tools provide the same features and functions as their mainframe counterparts.
However, to plan this move, carefully consider whether you are planning to preserve your current IT batch operations and development practices unchanged or whether your move heralds a change to embrace the new opportunities of event-based automation. If the former, consider adopting migration tools that preserve the operational characteristics of the mainframe (such as JCL emulation). If the latter, now may be a good time to consider adopting the advanced capabilities of a job scheduler to help you handle complex workload automation.
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Note 1: See the whitepaper “Job Scheduling on Windows.”
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Mike Gilbert is an independent consultant and owner of Legacy Directions where he is responsible for providing advisory services to the IT industry focusing on the issues around legacy technology. You can reach Mike at firstname.lastname@example.org.