Oracle 10g SPFILE corrupted

the SPfile is in binary format, if you edit it and save accidentally, your database will not able to startup with the normal startup command.

if you are on unix,

$ cd $ORACLE_HOME/dbs
$ strings spfilename  temp_pfile.ora

edit the temp_pfile.ora, clean it up if there is anything "wrong" with it.

then

SQL> startup pfile={FULL-PATH}temp_pfile.ora
SQL> create spfile from pfile;
SQL> shutdown
SQL> startup


Remember to backup your spfile.

Parameter values can only be modified with ALTER SYSTEM that will work after the STARTUP
command. For example :

SQL>  alter system set max_enabled_roles=20 scope=spfile;