PARAMETERS=USED, the default, specifies that only those PARAMETER constants which are actually used in the program unit are made known to the debugger.
PARAMETERS=ALL specifies that all PARAMETER constants are made known to the debugger. If many PARAMETER constants are defined this can greatly increase the size of the object module and executable image.
SYMBOLS
Controls whether the debugger receives local symbol definitions
for user-defined variables, arrays, (including dimension
information), structures, PARAMETER constants, and labels of
executable statements.
Unless /DEBUG=PARAMETERS=ALL is in effect, only those PARAMETER constants actually used in the program unit are made known to the debugger.
TRACEBACK
Controls the production of an address correlation table so that
the debugger and the run-time error traceback mechanism can
translate virtual addresses into source program routine names and
compiler-generated line numbers.
ALL
Same interpretation as (PARAMETERS=ALL,SYMBOLS,TRACEBACK).
NONE
Same interpretation as (PARAMETERS=USED,NOSYMBOLS,NOTRACEBACK).