Version 2 Record Header is written to the medium when using Version BB02 Block Headers. The memory representation of the record is identical to the old BB01 Record Header, but on the storage medium, the first two fields, namely VolSessionId and VolSessionTime are not written. The Block Header is filled with these values when the First user record is written (i.e. non label record) so that when the block is written, it will have the current and unique VolSessionId and VolSessionTime. On reading each record from the Block, the VolSessionId and VolSessionTime is filled in the Record Header from the Block Header.