can alternate index use in ESDS since it does not contain primary index? if yes can you explain?

yes,more than one alternate index can be used but it cannot
be used with batch-cobol programs.It can be used with
cics-cobol pgm.in ksds we ll use keys parameter but in esds
The RBA (relative byte addressing)is used to access the
records infact esds is faster than ksds.