gtpc3m1mConcepts and Structures

Module File Status Table

The module file status table (MFST) is a system table used to identify each module to the TPF system. For each module, the MFST contains status information (whether the module is accessible or not), its logical device type, and the linkage to its hardware address for use by the following functions:

The MFST is a device dependent table, which means it contains information about each of the four possible logical device types (DEVA, DEVB, DEVC, and DEVD) generated in a TPF system.

Once the online modules have been initialized (formatted) for online use, the module's volume serial number is used as a module identifier that maps to a symbolic module number. This symbolic module number is an index into the module file status table (MFST).

Another field in the MFST is the symbolic device address (SDA), which is related to a physical or hardware address for a module. The assignment of an SDA to a symbolic module number in the MFST is always done during a system restart or during an initial program load (IPL) with a procedure called roll call. Figure 33 shows the relationship between SDAs and symbolic module numbers.

Figure 33. Symbolic Module Numbers