The Oracle version starting of I. The starting in 1999 with version 6i, 8i and 9i, I signify "Internet" means stands for "Internet" and Oracle added the "I" to the version name to reflect support for the Internet with its built-in Java Virtual Machine (JVM). Oracle 9i added more support for XML in 2001.
Meaning of G in Oracle:
The starting in 2003 with version 10g and 11g, G signifies "Grid Computing" with the release of Oracle10g in 2003. Oracle 10g was introduced with emphasis on the "g" for grid computing, which enables clusters of low-cost, industry standard servers to be treated as a single unit. Upgrade Enterprise Manager 10g Grid Control Release 4 (10.2.0.4.0) or higher to Enterprise Manager 11g Grid Control Release 1 (22.214.171.124.0).
[Grid computing is a distributed architecture of large numbers of computers connected to solve a complex problem. In the grid computing model, servers or personal computers run independent tasks and are loosely linked by the Internet or low-speed networks. Computers may connect directly or via scheduling systems.]