Controlling the total number of users who can log on

You can control the number of users who can be logged on to TSO/E at one time. Several factors determine the total number of users. These factors are:

The number of available logons. You must ensure that you specify enough logons to accommodate the number of users you want to have logged on to TSO/E at one time. To specify the number of users who can be logged on at one time, use the USERMAX parameter in SYS1.PARMLIB member TSOKEYxx. For more information about the USERMAX parameter, see .
The number of address spaces that can execute concurrently in your system. Because each TSO/E user requires an address space, you must ensure that the total number of address spaces is at least as large as the number of available TSO/E logons. To specify the number of address spaces, use the following parameters in SYS1.PARMLIB member IEASYSxx: RSVNONR, RSVSTRT, and MAXUSER. For more information about these parameters, see .
The number of VTAM® APPL definition statements that have been specified at your installation. You must ensure that you have at least as many VTAM APPL definition statements as available TSO/E logons. For more information about specifying VTAM APPL definition statements, see Defining TSO/E address spaces to VTAM and .
The operating system that you are using.

Each of these factors can limit the number of users who can log on. For example, if you have fewer APPL definition statements than the number of available logons, the number of users who can be logged on concurrently is limited by the number of APPL definition statements.