bdfm1m0wMessages (System Error, Online, Offline) and Master Glossary

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active keys
The keys currently being used by the TPFDF product to select logical records (LRECs) in a subfile. Keys remain active until new keys are specified by a TPFDF macro or function, or until the subfile is closed.

add current file
A file that has subfiles in which a limited number of overflow blocks can be added. If a logical record (LREC) is added that causes the limit to be exceeded, the oldest LREC (or LRECs, if necessary) are deleted to make room. An add current file is indicated by bit 2 of symbol &SW00OP1 in the DSECT for the file. The maximum number of overflow blocks is indicated by symbol &SW00NOC. See also add current processing.

add current processing
The steps completed by the TPFDF product when a logical record (LREC) is added, using the DBADD macro or dfadd function, to an add current file. See also add current file.

Airline Control System (ALCS)
A transaction processing platform providing high performance, capacity, and availability, that runs specialized transaction processing applications. The ALCS environment runs application programs written for a TPF platform on an MVS system with little or no modifications. This includes application programs that are written using TPFDF macros and functions. Synonymous with TPF/MVS.

ALCS
Airline Control System.

algorithm
In the TPFDF product, an addressing mechanism that locates the prime block of a subfile. The database administrator specifies the algorithm type in the DSECT macro. See also algorithm argument.

algorithm argument
A value specified in TPFDF application programs to indicate the subfile that will be affected by a TPFDF macro or function. The algorithm argument can be a character string or number, depending on the type of algorithm defined in the DSECT for the file. An algorithm argument is also used to indicate a subfile in an intermediate index file or detail file. See also algorithm.

application program
A program written for or by a user that applies to the user's work. In a TPFDF environment, any program that requests a TPFDF service using a macro or function.