What are the Oracle Data Integrator GUI components ?

Oracle Data Integrator is made up of the following graphical user interface (GUI) components.
In the current releases of ODI all of these Graphical User Interface components are combined into Oracle Data Integrator Studio.

What is an agent in Oracle Data Integrator (ODI) ?

We know that there are run time and design time components in Oracle Data Integrator.

ODI agent is a run time component.

What is ODI agent ?

Oracle Data Integrator agent is a java program which will listen on a particular TCP/IP port. Agent can execute the scenarios when it is invoked from one of the ODI GUI modules or schedule these executions when it is started as a scheduler.

There are two types of ODI Agents available.

1. Standalone Java Agent :When request is received for a scenario execution, it start arranging the scenario and updates the status to work repository. A parent and child standalone agents can be configured in ODI studio to do the load balancing if there is a need to load balance between stand alone agents.
2. JavaEE agent : This agent is part of web logic and listens on a particular port. When request is received for a scenario execution, it start arranging scenario and updates the status to work repository. Load balancing is supported to through web logic clusters for a Java EE Agent.

Difference between Oracle Data Integrator features 10g, 11g and 12c

Differences between Oracle Data Integrator 12c and 11g: 

ODI 12c is the latest version of ODI.

1. loading multiple target tables as part of a single interface. Interface is termed as mapping in ODI 12c on wards.
2. Redesigned declarative flow-based user interface, reusable mappings, runtime performance enhancements, Oracle GoldenGate integration improvements, Big Data and XML improvements, Oracle Warehouse Builder integration.

complete change log is here
Oracle Data Integrator 11g and 10g:

1. ODI 11g has all the ODI components(Designer, Operator, Topology and Security) integrated together as Oracle Data Integrator Studio.
2. ODI 11g provides a Java API to manipulate both the design-time and run-time artifacts of the product. This API allows you for example to create or modify interfaces programmatically, create your topology, perform import or export operations, launch or monitor sessions. This API can be used in any Java SE and Java EE applications, or in the context of Java-based scripting languages like Groovy or Jython.
3. External Password Storage, to have source/target data servers (and contexts) passwords stored in an enterprise credential store. External Authentication, to have user/password information stored in an enterprise identity store (e.g.: LDAP, Oracle Directory, Active Directory), and ODI authenticating against this store. These two features let you optionally store critical information in dedicated storages and not within the ODI repository. The ODI Console may also use Oracle's single-sign on systems with ODI.