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NAME : HCPRDMBK
DESCRIPTION: RELOCATION DOMAIN BLOCK
DSECT : RDMBK
FUNCTION : HCPRDMBK defines a Relocation Domain. It heads the
chain of architecture description blocks (ARDBKs) used in
this domain which are pointed to by RDMARDP. The first in chain
is the canonical ARDBK for the domain. It defines the maximal
common subset of architectural features supported by all members
of the domain. The canonical ARD persists for the life of the
domain irrespective of any users logged on in this domain.
Other ARDBKs on this ARD chain are temporary. These
temporary ARDBKs are called "variant ARDs." They persist
while there are users logged on in the domain using the
architecture described by these ARDBKs. The variant ARDBKs
exist only on the member affected. They are created when logged
on users have to use an ARD that differs from the canonical to
avoid feature loss through domain operations such as h/w
configuration change or domain redefinition. Variant ARDBKs
are also defined when a user is forced out-of-domain to a
member not supporting all features of the current domain.
The RDMBK contains the member mask (RDMMMASK), each bit
of which represents a member of the SSI.
If a bit is set then this SSI member is included in
this domain. The member mask is used in
conjunction with the override mask (ARDHMASK)
to determine excluded and out-of-domain
relocations as follows:
OUT-OF-DOMAIN RELOCATIONS AS FOLLOWS:
DOM MEMBER CORRESP. ARD RELOCATION
MASK BIT OVERRIDE BIT INTERPRETATION
0 0 Not a candidate.
1 0 Is a candidate and a domain
member.
1 1 Domain member is excluded.
0 1 Out-of-domain-relocation
included member.
Out-of-domain Relocations (ODRs):
These occur when a guest is relocated to a system not included
in the membership of the domain. This is allowed for emergency
purposes and cases where a guest is being migrated to a new
domain. The ODR member becomes a temporary member of the domain
but is not eligible for general purpose relocation within
the domain. To effect an out-of-domain relocation the FORCE
DOMAIN option is required on the VMRELOCATE command. The
FORCE ARCHITECTURE option might also be required.
The RDMBK contains the last assigned sequence number (a token
applied to each ARD within a domain and unique within the
domain).
The ARD sequence number is incremented on allocation of a new
ARD within this domain but is never decremented. It serves to
indicate an ordering on the generations of ARD used within a
domain: older generations will have lower sequence numbers than
newer generations.
Also embedded within the RDMBK is a deferred lock for
serializing the RDMBK and associated ARDBK chains for this
particular domain.
The RDMBK also contains the domain name.
All RDMBKs for an SSI form a linked list which is anchored from
the VAABK located at externalized label HCPARDVA.
LOCATED BY : VAASSIP -- SSI domain RDMBK only
VAASRDP -- Chain singleton domain RDMBKs only anchored
in the VAABK
VAARDMP -- Chain of all RDMBKs anchored in VAABK
ARDHRDM -- ARDBK header (field of ARDHDR)
RDMSRDP -- Forward pointer for VAASRDP chain
RDMNEXT -- Forward pointer for VAARDMP chain
CREATED BY : HCPARDIN creates default domain RDMBKs at initialization
HCPRLJRD creates RDMBKs for installation-defined domains
in the SYSTEM CONFIG file
HCPRDM relocation domain synchronization at SSI Join time
and during DEFINE RELODOMAIN command processing
DELETED BY : Relocation domains cannot be deleted
REFERENCES : HCPARDBK - ARchitecture Description block
SERIALIZED : VAAXLK (local) for RDM chain local to a member
VAAXLK (X-System) for RDM chain across the SSI
RDMLOCK for one RDM and dependent ARD chain with a member
RELOCATION CONSIDERATIONS : This structure may be mirrored to multiple members of the
SSI. It is not relocated, but through actions to a domain or
member of a domain this structure might be updated or
deleted. Either of these will require those changes to be
mirrored to other members of the SSI.
COMPATIBILITY AND MIGRATION CONCERNS : None
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