Final answer:
The IPL text is contained in the SYSRES volume, which is crucial for booting a mainframe system. SYSCAT, SYSDLB, and SYSZOS are not associated with containing the IPL text.
Step-by-step explanation:
The IPL (Initial Program Load) text, which is essential for the booting process of a mainframe system, is contained in the SYSRES (System Residence) volume. SYSRES is a direct access storage device (DASD) volume that contains the nucleus or the permanent system residence portion of the operating system. It is where the system begins to load when powered on or restarted. The volumes SYSCAT, SYSDLB, and SYSZOS serve different purposes and do not contain the IPL text.