Solutions including IBM Rational ClearQuest for System i and IBM Rational ClearCase for System i provide a strategic advantage over competitive offerings for managing software resources and application development processes. Explore typical IBM System i scenarios and the potential integration and synergy with third-party Software Configuration Management (SCM) software.
Understanding traditional i5/OS program source management
Typically, the i5/OS® source code files for programs such as RPG, COBOL, and CL are stored as members of a source physical file in a library (see Figure 1).
Figure 1. Typical i5/OS source code storage libraries
Often, developers create multiple libraries on a development machine or logical partition (LPAR) that implement the following:
- Development testing environment
- Integration testing environment
- Quality assurance or acceptance testing environment
- Production environment
Note: An environment is a collection of libraries that support test and production systems. An environment can contain a program library, a data collection library, or other libraries containing shared i5/OS objects and resources, such as message files, data queues, data areas, and text files.
Current third-party (non-IBM) Software Change Management (SCM) software vendors create an inventory of source members in a database file that maps the source files to the environment. The SCM software also identifies compiled executable or supporting resources and creates entries in an inventory database.
A checkout operation in a traditional SCM system copies the source code for a source-based object to the developer’s library. The SCM software creates a list of objects and generates command language (CL) to promote source and executable object files to the next environment. Traditional SCM systems define promotion as the move or copy between the following:
- From the developer’s library to the integration library
- From the integration library to the quality assurance library
- From the quality assurance library to the production library
The developer defines the number of environments and the libraries in the environment. The SCM system requires that the customer map object types to libraries in each environment. For example, a physical file (*FILE) with the attribute PF-DTA could be mapped to each library in each environment. The current SCM vendors' tools promote objects with or without source as a complete file or object move or copy operation.
The vendor’s implementation of i5/OS security protects the objects. i5/OS has an excellent security mechanism, but it is dependent on how you implement it. Often developers have excessive access rights, such as *ALLOBJ, which basically bypasses all security checking, to facilitate their work on the system. Third-party SCM vendors use reports and analysis techniques to detect modifications to programs outside their software’s control. A key part of their compliance process is to review these reports on a regular basis.
Learning about the Rational ClearCase difference
The implementation of IBM Rational ClearCase introduces a major difference in operation and configuration for the System i developer.
ClearCase is implemented using the Remote System Explorer (RSE) feature of the WebSphere® Development Studio Client (WDSC) to import all source files from a source physical file on the System i computer to an iSeries project on the WDSC. This process physically copies all source files to the workstation running the WDSC (see Figure 2).
Figure 2. ClearCase initial load process
Once the objects are transferred to the WDSC workstation, the source members are then checked into the ClearCase Virtual Object Base (VOB) repository on the ClearCase server.
At this point, you can back up source files on the System i workstation and delete them from the system. The authoritative repository is now the ClearCase VOB. All developers must be registered as authorized ClearCase users, and their i5/OS security access rights no longer affect source management.
Exploring the WDSC-managed build scenario
You can automate the management of source and objects throughout a multiple environment development scenario using the WDSC with customization and some custom CL programs.
Figure 3. WDSC-managed build scenario
Figure 3 illustrates a WDSC-managed build and deployment scenario. In the example, a developer checks out program source from the ClearCase VOB to the WDSC. Programs are compiled and tested for unit testing purposes to a developer's private library on i5/OS. This process requires that source files be transferred to the System i workstation for the life of the compile, but the files can be deleted upon a successful compilation. The source file in the ClearCase VOB is the authoritative source file. In this example, you can deploy to integration, quality assurance, and production libraries by invoking an action in the WDSC and potentially invoking a customized CL program that could compile resources to the target library.
Figure 4. Third-party integrated environment scenario
Figure 4 illustrates the modification and movement of a program through a typical development lifecycle. The developer checks out an object from ClearCase and modifies the program -- compiling and testing using his library and source files on the i5/OS workstation. When the project is completed, the object is checked into the ClearCase repository.
The developer can then use the third-party SCM tool to promote executable objects from the developer’s library to integration to quality assurance and, finally, to production. The third-party SCM tool could then distribute (copy) the executable objects from the production library on the customer’s development machine to any number of target production machines.
Note that while there is synergy between ClearCase and traditional SCM vendor software for i5/OS objects, there is no synergy in respect to J2EE, Java™, or other Web resources that the SCM vendors manage in the same manner as RPG, COBOL, DDS, CL, or other i5/OS objects.
You can configure Rational ClearCase and the WebSphere Development Studio Client to work in a standalone environment and manage the creation, modification, and promotion of i5/OS objects throughout the development lifecycle. The software also works with existing third-party SCM solutions that focus on promoting and distributing objects between environments.
In either scenario, Rational ClearCase provides superior management of the development process, protects resources throughout the development process, and provides superior security and integrity to help you meet rigorous audit requirements.
Learn
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Rational change and release management: Learn more about how IBM Rational ClearCase can help System i customers.
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ClearCase and ClearQuest: Visit these IBM developerWorks areas to see a variety of technical resources to help you deploy those solutions in your enterprise.
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Bob Cancilla has over 30 years of experience developing large-scale enterprise systems, primarily as an IT executive and as an IT customer in the insurance industry. His expertise includes IT methodology and strategy, System Development Lifecycle (SDLC), security, business planning, business intelligence, and business governance. He is currently a product market manager for the IBM Software Group, Rational, working on Rational tools for System i and System z™ platforms.
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