IDA019RB
IDA019RB is a CSECT within load module IDA019L1. IDA019RA (VSAM DIRECT RECORD LOCATE) invokes it to search the index of a VSAM KSDS data set to find the relative byte address (RBA) of the required data record's control interval during a direct or skip-sequential GET request.
Reference Sources
MVS/Extended Architecture: Virtual Storage Access Method (VSAM) Logic, LY26- 3970.