Mainframe, MVS and zOS Discussion

What is meant by BDAM datasets? What is the difference between BDAM and VSAM datasets. Any idea please.

Basic Direct Access Method -- allows retrieval of data by relative block number. VSAM RRDS is the equivalent VSAM data type. With BDAM, you have a method to generate the block number (hash or sequence number or whatever) and that block contains the data record. There is no key required, you can read the one block of data you need, but the only way to sequentially access the blocks is one by one (block 0 followed by block 1 followed by block 2 ...). Generally BDAM files are preformatted to prevent retrieval issues if you attempt to read uninitialized data.

Thank you Robert.

Sorry for coming back late...