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NAME : HCPOSIBK
DESCRIPTION: OS Info
DSECT : OSIBK
FUNCTION : The OSIBK describes the contents of the OS Info data area
which is a data interface to stand-alone dump. This is a
singleton data structure.
LOCATED BY : HCPDMOSI - allocated in nucleus. IPL sets the location.
PFXOSIAD - in each PFXPG as well as absolute page 0. The
absolute page 0 location is the one used by
stand-alone dump to locate the data area.
For SAPL, located in a page of storage within HCPSAL.
For DDR, located in a page of storage within HCPDDR.
CREATED BY : Allocated in CP nucleus and initialized in stages during
CP initialization. Never changed after IPL. See HCPDMO
for details of data area initialization.
For SAPL, the OSIBK is located in a page of storage
within HCPSAL and initialized early during its
processing. In most cases, the OSIBK is overlaid by
the module being loaded during the end of SAPL's
processing. Whether the overlay occurs depends on the
load origin that was requested.
For DDR, the OSIBK located in a page of storage within
HCPDDR and initialized early during its processing if
DDR is running stand-alone. It is never changed after
being initialized.
DELETED BY : Never deleted.
REFERENCES : None
SERIALIZED : CP initialization (uni-processor).
SAPL and DDR run entirely in uni-processor mode.
RELOCATION CONSIDERATIONS : None
COMPATIBILITY AND MIGRATION CONCERNS : - The format and content of the OS Info is determined by
the level of the stand-alone dump function supported by
the VM release.
- The level of the stand-alone dump support is determined
by the level of VLP distributed with VM.
- The OSIVERMJ and OSIVERMN fields document the version
and thus the format and content of the OS Info area.
OSIVERMJ (version_major) -
- For incompatible interface changes, for example when
new mandatory fields are introduced to the OS Info
structure, the major version will be increased. When
the stand-alone dump utility finds an OS info structure
that has a higher version number, stand-alone dump will
stop with a disabled wait PSW. Therefore when a major
version update is done, VM users have to prepare their
dump disks with the new version of the stand-alone dump
utility.
OSIVERMN (version_minor) -
- For compatible interface changes, for example when new
optional fields are introduced to the OS info
structure, the minor version will be increased. When
the stand-alone dump utility finds an OS info structure
that has a higher version number, stand-alone dump will
ignore the new optional features and will do everything
that was defined for its own lower version number.
- version_minor resets to 1 when version_major increases
NOTES : - Must be allocated on a page boundary.
- Must be 4K in length.
- Refer to the design document "RAS1211 Support for
stand-alone kdump" from IBM LTC. That document defines
the format and content of OS Info.
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