When the USERDATAFILE Cannot Be Changed

The SYSTEM/USERDATAFILE is frozen in the following situations:

  • During a COPY operation

  • For a short period in a RECALL run

  • At the end of a CREATE run

In these situations, the USERDATAFILE is unavailable for modification. Programs attempting to alter the file—to change passwords, for example-–are suspended in most cases. Some programs that resist suspension deny changes when the file is frozen. Normal read-only access (as for log on) is permitted to a frozen file.

If a process attempts to modify the SYSTEM/USERDATAFILE while the file is frozen and the process is waiting, the USERDATAFILE procedure issues the message “WAITING FOR USERDATA FILE FROZEN BY TASK <n>.” The construct “<n>” represents the mix number of the task that has frozen the USERDATAFILE. In many cases, this task is MAKEUSER performing a COPY or CREATE statement.

If MAKEUSER finds that the file is already frozen, MAKEUSER terminates with an error message. This situation implies that more than one MAKEUSER run was attempted at the same time.

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