8.1. Introduction to program status word (PSW)

One very important piece of information that will be crucial to your ability to diagnose a problem on z/OS is the program status word, more commonly referred to as the PSW. The PSW includes the instruction address, condition code, and other information to control instruction sequencing and to determine the state of the CPU. The active or controlling PSW is called the current PSW.

The PSW is so important because it keeps track of the progress of the system and the executing program. The current PSW usually points to the address of the next instruction to be executed. In some specific cases the PSW will point to the address of the failing instruction. This occurs when the interrupt code is 0010, which ...

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