Begin Named Group (BNG) structured field
When ACIF processes an AFP data stream print file containing page groups, it checks for an FQN type X'01' triplet on each BNG structured field.
If the FQN triplet exists, ACIF uses the value when it creates an FQN type X'0D' triplet on the corresponding Index Element (IEL) structured field in the index object file. ACIF appends an eight-byte rolling sequence number to ensure uniqueness in the name. If no FQN triplet exists, ACIF creates one. Here too, ACIF appends a rolling, eight-byte EBCDIC sequence number to ensure uniquely named groups, up to a maximum of 99␠999␠999 groups within a print file.
When ACIF indexes a print file, it creates the BNG structured fields. It assigns a rolling eight-byte EBCDIC sequence number to the token name (for example, 00000001 where 1=X'F1'). The sequence number begins with 00000001 and is incremented by 1 each time a group is created. ACIF also creates an FQN type X'01' triplet by concatenating the specified index value (GROUPNAME) with the same sequence number used in the token name. If the value of the index specified in GROUPNAME is too long, the trailing bytes are replaced by the sequence number. This occurs only if the specified index value exceeds 242 bytes in length. A maximum of 99␠999␠999 groups can be supported before the counter wraps. This means that ACIF can guarantee a maximum of 99␠999␠999 unique group names.