Mainframe systems are designed to be used by large numbers of people. Most of those who interact with mainframes are end users— people who use the applications that are hosted on the system. However, because of the large number of end users, applications running on the system, and the sophistication and complexity of the system software that supports the users and applications, a variety of roles are needed to operate and support the system.

Figure 1. Who's who in the mainframe world?

In the IT field, these roles are referred to by a number of different titles, such as:

• System programmers
• System administrators
• Application designers and programmers
• System operators
• Production control analysts

In a distributed systems environment, many of the same roles are needed as in the mainframe environment. However, the job responsibilities are often not as well-defined. Since the 1960s, mainframe roles have evolved and expanded to provide an environment in which the system software and applications can function smoothly and effectively and serve many thousands of users efficiently. While it may seem that the size of the mainframe support staff is large and unwieldy, the numbers become comparatively small when one considers the number of users supported, the number of transactions run, and the high business value of the work that is performed on the mainframe.

Mainframe activities, such as the following, often require cooperation among the various roles:

• Installing and configuring system software
• Designing and coding new applications to run on the mainframe
• Introduction and management of new workloads on the system, such as batch jobs and online transaction processing
• Operation and maintenance of the mainframe software and hardware