Terminate processing

You can terminate a program or a process by pressing the attention interrupt key. For instance, if you were executing a program and the program went into a loop, you could press the attention interrupt key to terminate processing.

Example
If you entered a command such as CALL and wanted to get out of the process, press the attention interrupt key. You then see another READY mode message.
 
READY
CALL
 ENTER DATA SET NAME -
 |
 READY