How to find out hidden and system Parameters?

System Parameters Purpose: Reports all system parameters, including the hidden ones

select
nam.indx+1 numb,
nam.ksppinm name,
val.ksppstvl value,
nam.ksppity type,
val.ksppstdf is_default,
decode(bitand(nam.ksppiflg/256,1),
1,'True',
'False'
) is_session_modifiable,
decode(bitand(nam.ksppiflg/65536,3),
1,'Immediate',
2,'Deferred' ,
3,'Immediate',
'False'
) is_system_modifiable,
decode(bitand(val.ksppstvf,7),
1,'Modified',
4,'System Modified',
'False'
) is_modified,
decode(bitand(val.ksppstvf,2),
2,'True',
'False'
) is_adjusted,
nam.ksppdesc description
from
x$ksppi nam,
x$ksppsv val
where
nam.indx = val.indx
and
nam.ksppinm like '&&PARAMETER%';

Session Parameters

select
nam.indx+1 numb,
nam.ksppinm name,
val.ksppstvl value,
nam.ksppity type,
val.ksppstdf is_default,
decode(bitand(nam.ksppiflg/256,1),
1,'True',
'False'
) is_session_modifiable,
decode(bitand(nam.ksppiflg/65536,3),
1,'Immediate',
2,'Deferred' ,
3,'Immediate',
'False'
) is_system_modifiable,
decode(bitand(val.ksppstvf,7),
1,'Modified',
4,'System Modified',
'False'
) is_modified,
decode(bitand(val.ksppstvf,2),
2,'True',
'False'
) is_adjusted,
nam.ksppdesc description
from
x$ksppi nam,
x$ksppcv val
where
nam.indx = val.indx