Example: Record format *VB

This is an example of record format *VB, which consists of graphics with explanations.

Variable-length, blocked, unspanned (*VB).

Figure 1. Variable-length, blocked, unspanned (*VB)
This diagram shows a VV
WW connected to Record A data. Below this, is XX YY, Record A and Record B.
The XX YY has a block 1 pointing at it. Below this is VV WW and a Record B
data.

This diagram shows a VV
WW connected to Record A data. Below this, is XX YY, Record A and Record B.
The XX YY has a block 1 pointing at it. Below this is VV WW and a Record B
data.

XX and YY make up the BDW. XX is the length of all records plus the length of the BDW (4 bytes). YY represents currently reserved fields and must be 00. XX should be the actual length of the data block that is written.

Figure 2. Record A mapping
This diagram shows Record
A, which is comprised of a VV WW connected with a Record A data.

Record A has its own mapping by including the RDW. VV and WW make up the RDW. VV is the length of the record plus the length of the RDW (4 bytes). WW are currently reserved fields and must be 00. VV should be the actual length of record data A plus the length of the RDW (4 bytes). The actual length of the data block equals the sum of:

The VV value for ALL records.
The length of the BDW (4 bytes).