Open System Services Management and Operations Guide (G06.30+, H06.08+, J06.03+)

Figure 3 OSS File-System Components
An application running in the OSS environment makes calls for access to an OSS file through
function calls in the OSS file-system library. The OSS file-system library is present in each processor.
The library consists of functions in a shared run-time library (SRL) and in the system library. OSS
file-system library functions are described in the Open System Services System Calls Reference
Manual and in the Open System Services Library Calls Reference Manual.
When the application opens an OSS file, an OSS name server locates the correct file within the
correct fileset, based upon configuration information you have supplied to the OSS Monitor for
that fileset’s catalog.
An OSS file manager process named $ZFMnn runs in each processor (nn indicates the processor
number). The OSS file manager starts automatically when the processor starts; if the OSS file
manager terminates abnormally, it takes down the processor. Its processor can be shut down
without first stopping the process, but you should stop all applications with open OSS files first.
The OSS file manager automatically:
• Allocates and initializes the PXS extended segment and OSS file-system cache
• Satisfies OSS regular file cache-related requests from disk processes
The PXS extended segment is used to share OSS file-system data structures within that processor.
The PXS extended segment is created and managed without system manager or operator
intervention.
34 Introducing Open System Services