The restart program (CTKS) invokes programs CNAE and CNAJ to send the
status of a processor to every other active processor in the complex.
CTKS checks each processor during restart to determine if the processor
was previously inactive. If the processor was inactive, CTKS initiates
a software IPL to synchronize this processor with the others in the
complex.
Program CNPY is called to ensure that only one processor is active if the
IPL program designated the processor as the first in the IPL chain.
Certain restart programs ensure that all loosely coupled processors access
the same DASD via the same channel and control unit.
See the ZRSTT command in TPF Operations.
These programs also maintain the status of each processor and make the status
available to the other processors in the complex.
In an MDBF system, the basic subsystem must be cycled up before any other
subsystem; no subsystem can be in a higher system state during
cycle-up.