The .DBT file is a “core dump” of three things:

  • The information in SYSVOLUMES;

  • The information in SYSTABLES

  • The set of known filing systems used in the database.   This list is maintained by operations such as the OPEN statement, which will add a filing system function name to the list after the filing system successfully completes its INSTALL operation. The list is used by the system for two main operations: FLUSH and UNLOCK ALL. When either one of these BASIC+ commands is executed, the engine sends the corresponding call to each known filing system.

The .DBT file is @rm-delimited, with volume records, followed by a blank record, followed by table records, followed by a blank record, followed by the filing system list.

The volume records are @fm-delimited, and contain seven fields:

  1. The SYSVOLUMES key;

  2. Field 1 of the SYSVOLUMES record;

  3. Field 2 of the SYSVOLUMES record;

  4. Field 3 of the SYSVOLUMES record;

  5. Field 4 of the SYSVOLUMES record;

  6. Blank;

  7. Field 6 of the SYSVOLUMES record.

The table records are @fm-delimited, and contain five fields:

  1. The SYSTABLES key;

  2. Field 1 of the SYSTABLES record;

  3. Field 2 of the SYSTABLES record;

  4. Field 3 of the SYSTABLES record;

  5. Field 4 of the SYSTABLES record;

The filing system list is @fm-delimited.

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