Description of the DBD variable segment

Note

When the counter value is too large for its field in the database trailer segment, an overflow occurs. For any overflow, the overflow counter index indicates the offset of the element that overflowed into the overflow fullword counter. If more than one element overflowed or if the first element overflowed into the overflow fullword counter, an additional database trailer segment is created to contain the overflow. This additional segment is pointed to by the overflow pointer at decimal offset 015.

The additional database trailer segment contains the final tally of all the elements that overflowed unless overflow occurs again. If overflow occurs again, the overflow fullword counter in the additional segment indicates the first element within the segment that overflowed. Any additional overflows are controlled similarly.