Oracle Database Hidden Parameters

REM Script for getting undocumented init.ora
REM
COLUMN parameter FORMAT a37
COLUMN description FORMAT a30 WORD_WRAPPED
COLUMN "Session Value" FORMAT a10
COLUMN "Instance Value" FORMAT a10
SET LINES 100
SET PAGES 0
SPOOL _hidden_ora_params.txt
SELECT
a.ksppinm "Parameter",
a.ksppdesc "Description",
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 '/'
/
SPOOL OFF
SET LINES 80 PAGES 20
CLEAR COLUMNS