z/OS MVS Program Management: User's Guide and Reference
SA23-1393-00
You can execute a program object that resides in a z/OS UNIX file either
by using z/OS UNIX commands
or through the BPXBATCH facility. You cannot execute such a program
object from an MVS™ batch job
using EXEC PGM=.
z/OS UNIX does
not support alternate entry points. All aliases in z/OS UNIX program objects
are processed as though they were true aliases.
Overlay format modules are not supported in z/OS UNIX files.