gtpc3m1g | Concepts and Structures |
The dynamic requirements for file storage are satisfied by the use of areas on modules known as pools. The allocation of a pool record area to physical devices is done by offline programs. Several pool record types are defined by the system, based upon record attributes in order to allocate pool areas on modules. Record attributes are described in Data Record Attributes.
Moreover, each record within a pool record type is dispensed on an as needed basis. This means the availability status (either available or unavailable) of each record within a pool record type is managed by system service routines within the TPF system, through the use of pool directories. (Note that no such management is performed on records within a fixed record type; in essence, the system views the fixed records as being dispensed during the system generation process.)