Difference Between Oracle apps 11i & R12

Summary of Changes :

Component	Release 11i	Release 12
Database	9.2	10.2
Developer	6i	10i
Application Server	1.0	10.1
Client Plug-in	Jinitiator	SUN JRE
Java Containers	Jserv	OC4J

Changes in Detail :

APPMGR
	OLD	NEW
APPL_TOP	$HOME/<SID>appl	$HOME/apps/apps_st/appl
COMMON_TOP	$HOME/<SID>comn	$HOME/apps/apps_st/comn
ORACLE_HOME	$HOME/<SID>ora/8.0.6	$HOME/apps/tech_st/10.1.2
IAS_ORACLE_HOME	$HOME/<SID>ora/iAS	$HOME/apps/tech_st/10.1.3
ORACLE
	OLD	NEW
ORACLE_HOME	$HOME/<SID>db/10.2.0	$HOME/db/tech_st/10.2.0
ORADATA	$HOME/<SID>data	$HOME/db/apps_st/data
INST_TOP (New Addition)
	OLD	NEW
INST_TOP	NA	$HOME/inst/apps/<context_name>

What’s new in Oracle Apps R12

Key points to Note:

1. Oracle Applications Release 12 is the latest release in the chain of E-Business Suite Releases by Oracle.
2. This release came up with the new file system model
3. Autoconfig will not write anything in APPL_TOP, COMMON_TOP area in R12.
4. All instance specific configurations, log files are written in INST_TOP area. This home provides the ability to share Applications and technology stack.

R12 new features

1. Applications Server 9i is replaced by 10g (10.1.3.X)
2. Forms & Reports Version 6i (8.0.6) are replaced by Forms & Reports Version 10g i.e. 10.1.2.X
3. mod_jserv is replaced by oc4j
4. Java/ JDK version 1.3.X or 1.4.X will be replaced by JDK 1.5.X

Techstack Components Changes

• Database (RDBMS_ORACLE_HOME) - 10.2.0.2
• FORMS ORACLE_HOME (8.0.6 ORACLE HOME equivalence) - 10.1.2
• OC4J_ORACLE_HOME (iAS ORACLE_HOME equivalence) - 10.1.3

File system level changes

• A new top INSTANCE_TOP is introduced in Release 12 for configuration and log files along with the other TOP's in existing in 11i.
• All instance specific configurations, log files are written in INST_TOP area. 
• This home provides the ability to share Applications and technology stack.

What is INSTANCE TOP 

• Instance home is the top-level directory for an applications instance which is known as Instance Home and is denoted the environment variable $INST_TOP. 
• This contains all the config files, log files, SSL certificates etc.

Advantages of new INSTANCE HOME

• The additional Instance Home makes the middle tier easier to manage and organized since the data is kept separate from the config files.
• The Instance Home also has the ability to share the Applications and Technology stack code across multiple instances.
• Another advantage of the Instance Home is that the autoconfig writes only in INST_TOP so APPL_TOP and ORACLE_HOME can also be made read only file system if required.