/rough approach on ( enough to understand )
there are two categories/types of esoterics
the first one is the hardware denomination
unit=3390 will include all the devices classified as 3390
( manufacturer' s decision)
same thing with tapes unit=3490 ( for example)
and exists by default without the need of being defined
the other as in Your question are real esoterics/nicknames
and are installation dependent
- they are defined by the &SYSTEMGROUP according to some
installation standards and encompass only a specific address range/ranges
they do not exist by default and need to be defined
unit=3390 will refer to all the 3390 devices
unit= stor will refer only to the devices specified in the EDT definition
( EDT ==> Eligible Device Table )
