COMM-AREA - this is ur working storage variable which could be given any name as u might know.
It contains values which u want to use for the next execution(pseudo-conversational programs) of same program or any other program ur calling.
To retain the value for the next execution of the same program u have to write the following code during return...
DFHCOMMAREA- it is defined in the linkage section which receives the values passed from the first execution of the same program or from some other program which has linked to this program.
u can use the values from DFHCOMMAREA directly or by moving to COMM-AREA variables.