Mainframe, MVS and zOS Discussion

Another question which was touch to answer was what is RDW in VSAM?

I know RDW is Record Descriptor Word but this has it's use in the VB file. Will the concept of RDW apply to VSAMs also? Please guide.

VSAM does not have an RDW. However, a CI has a RDF (Record Definition Field) which works similarly to an RDW. The RDF, though, is stored external of the record unlike the RDW.