019

Explanation
During initial program load (IPL), an unexpected
program interruption occurred. IPL did not complete loading the resident
nucleus. If this wait state occurred because the IPL program is in
error, a stand alone dump should be taken so that the cause of the
program error can be diagnosed.
The problem is one of the following: The operator pressed START during system initialization.
The IPL program is in error.
The storage in which IPL resides is failing.
The IODF being used for IPL may be empty.

System action
The system enters a non-restartable wait state.

Operator response
Do one of the following: If this wait state occurred because an operator pressed the START
key during system initialization, let the IPL continue. It is not
necessary to reIPL; the system will start the waiting processors automatically.
Make sure the SYS1.NUCLEUS data set does not have secondary extents.
If there are no secondary extents, the error is probably the result
of a hardware problem. Contact hardware support. When the problem
has been corrected, reIPL the system.
Ensure that the IPL text program installed is at the correct level
for the operating system.  If not, reinstall IPLTEXT as described
in the MVS™ program directory.

Source
Initial program load (IPL)