I/O Servers Provide
Border Patrol – Separates the Database from the program.
Performance – Consolidates open data paths which reduces the size of the PAG and the program
Security – By defining the table as 1. public exclude 2 owned by a profile (with no sign-on capabilities) you are providing a high level of security. The only access is threw the I/O server.
The compelling reason for using an I/O server is to manage data definition changes as in expanding fields or getting the data type right.