How To Change The Oracle Hidden Parameters In Oracle 10g [ID 315631.1]

Q1: How to query this hidden initialization parameters in sql ?

SELECT
a.ksppinm "Parameter",
b.ksppstvl "Session Value",
c.ksppstvl "Instance Value"
FROM
x$ksppi a,
x$ksppcv b,
x$ksppsv c
WHERE
a.indx = b.indx
AND
a.indx = c.indx
AND
a.ksppinm LIKE '/_%' escape '/'

Q2: How to change these hidden parameters?

1) alter system set "<_parameter-of-choice>" scope=spfile and bounce the database.

2) alter..session set command for session level

[@more@]select i.ksppinm name,
i.ksppdesc description,
cv.ksppstvl value,
cv.ksppstdf isdefault,
decode(bitand(cv.ksppstvf, 7),
1,
'MODIFIED',
4,
'SYSTEM_MOD',
'FALSE') ismodified,
decode(bitand(cv.ksppstvf, 2), 2, 'TRUE', 'FALSE') isadjusted
from sys.x$ksppi i, sys.x$ksppcv cv
where i.inst_id = userenv('Instance')
and cv.inst_id = userenv('Instance')
and i.indx = cv.indx
and i.ksppinm like '/_%' escape '/'
order by replace(i.ksppinm, '_', '');