Manual steps involve in upgradation of Oracle 9i to 10g

1. Install 10g Software in a new Oracle Home.
2. Run the pre-Upgrade utility ($ORACLE_HOME/rdbms/admin/utlu1011.sql)
3. If any recommendations from pre-Upgrade utility make the changes as suggested (Like at Kernal Level, Memory level or OS level)
4. Shutdown the database to be upgraded.
5. Create / Setup new environment pointing to new 10g Home for the upgrded Home.
6. Switch the new Oracle database 10g home and startup the 10g database
7. (SQL> Start upgrade)
8. Create SYSAUX tablespace
9. Run the upgrade scripts (u0902000.sql)
10. Run the post upgrade status script (utlu101s.sql TEXT)
11. Re-compile any PL/SQL, JAVA invalid code.

SHMMAX 4294967295 Maximum size of a single shared memory segment
SHMMIN 1 Minimum size of a single shared memory segment
SHMMNI 100 Maximum number of shared memory segments in entire system
SHMSEG 10 Maximum number of shared memory segments one process can attach
SEMMNS 2000 Maximum number of semaphores in entire system
SEMMSL 1000 Maximum number of semaphores per set
SEMMNI 100 Maximum number of semaphore sets in entire system
SEMOPM 100 Maximum number of operations per semop call
SEMVMX 32767 Maximum value of a semaphore

NOTE: Upgrade Path
7.3.3 (or lower) -> 7.3.4 -> 8.1.7.4 -> 10.2
7.3.4 -> 8.1.7.4 -> 10.2
8.0.n -> 8.1.7.4 -> 10.2
8.1.n -> 8.1.7.4 -> 10.2
Direct Upgrade possible ->8.1.7.4, 9.0.1.4, 9.2.0.4, 10.1.0.2
Direct Upgrade not supported from 8.1.6, 8.1.5, 8.0.5, 8.0.4,8.0.3, 7.3.4