Changes to TPFDF index LRECs

TPFDF databases that are migrated to use TPFDF FARF6 support use a different layout for index file LRECs managed by TPFDF. Instead of 5‑byte areas that contain a 4‑byte file address reference and a 1‑byte record code check (RCC), the existing RCC field contains the value X'01'. The original 4‑byte file address field contains a displacement from the start of the LREC to a new 10‑byte area.

This 10‑byte area consists of an 8‑byte field that contains the referenced file address, a 1‑byte RCC, and a 1‑byte spare field. The file address is either a FARF6 file address or a FARF 3/4/5 file address in 4x4 mode.

The TPFDF system code recognizes the value X'01' in the existing RCC field and adjusts its processing to correctly read the referenced file address. You must specify the new FAL=8M parameter value in the DBDEF macro to indicate to the TPFDF recoup and CRUISE utilities that the index LREC uses the 8‑byte file address format.

For new TPFDF databases that are using the 8-byte file address headers, the DBDEF macro must specify the FAL=8 parameter value and IMI #BIT3 in the DBDEF must be turned on so that the utilities correctly process an 8-byte reference.