The application designer gathers requirements from business systems analysts and end users. The application programmer is responsible for developing and maintaining application programs.

The tasks of designing an application and developing one are distinct enough to treat each in a separate learning module. In larger z/OS® sites, separate departments might be used to carry out each task. This section provides an overview of these job roles and shows how each skill fits into the overall view of a typical application development life cycle on z/OS.

The application designer is responsible for determining the best programming solution for an important business requirement. The success of any design depends in part on the designer's knowledge of the business itself, awareness of other roles in the mainframe organization such as programming and database design, and understanding of the business's hardware and software. In short, the designer must have a global view of the entire project.

Another role involved in this process is the business systems analyst. This person is responsible for working with users in a particular department (accounting, sales, production control, manufacturing, and so on) to identify business needs for the application. Like the application designer, the business systems analyst requires a broad understanding of the organization's business goals, and the capabilities of the information system.

The application designer gathers requirements from business systems analysts and end users. The designer also determines which IT resources will be available to support the application. The application designer then writes the design specifications for the application programmers to implement.

The application programmer is responsible for developing and maintaining application programs. That is, the programmer builds, tests, and delivers the application programs that run on the mainframe for the end users. Based on the application designer's specifications, the programmer constructs an application program using a variety of tools. The build process includes many iterations of code changes and compiles, application builds, and unit testing.

During the development process, the designer and programmer must interact with other roles in the enterprise. The programmer, for example, often works on a team of other programmers who are building code for related application modules.

When the application modules are completed, they are passed through a testing process that can include functional, integration, and system tests. Following this testing process, the application programs must be acceptance-tested by the user community to determine whether the code actually accomplishes what the users desire.

Besides creating new application code, the programmer is responsible for maintaining and enhancing the company's existing mainframe applications. In fact, this is frequently the primary job for many application programmers on the mainframe today. While many mainframe installations still create new programs with COBOL or PL/I, languages such as Java™ have become popular for building new applications on the mainframe, just as on distributed platforms.