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E.1 Partitions

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   The partitions of a distributed program are classified as either active or passive.

Post-Compilation Rules

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   An active partition is a partition as defined in 10.2. A passive partition is a partition that has no thread of control of its own, whose library units are all preelaborated, and whose data and subprograms are accessible to one or more active partitions.
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   A passive partition shall include only library_items that either are declared pure or are shared passive (see 10.2.1 and E.2.1).
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   An active partition shall be configured on a processing node. A passive partition shall be configured either on a storage node or on a processing node.
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   The configuration of the partitions of a program onto a distributed system shall be consistent with the possibility for data references or calls between the partitions implied by their semantic dependences. Any reference to data or call of a subprogram across partitions is called a remote access.

Dynamic Semantics

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   A library_item is elaborated as part of the elaboration of each partition that includes it. If a normal library unit (see E.2) has state, then a separate copy of the state exists in each active partition that elaborates it. The state evolves independently in each such partition.
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   An active partition terminates when its environment task terminates. A partition becomes inaccessible if it terminates or if it is aborted. An active partition is aborted when its environment task is aborted. In addition, if a partition fails during its elaboration, it becomes inaccessible to other partitions. Other implementation-defined events can also result in a partition becoming inaccessible.
8/1
     For a prefix D that denotes a library-level declaration, excepting a declaration of or within a declared-pure library unit, the following attribute is defined:
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   D'Partition_ID
Denotes a value of the type universal_integer that identifies the partition in which D was elaborated. If D denotes the declaration of a remote call interface library unit (see E.2.3) the given partition is the one where the body of D was elaborated.

Bounded (Run-Time) Errors

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    It is a bounded error for there to be cyclic elaboration dependences between the active partitions of a single distributed program. The possible effects are deadlock during elaboration, or the raising of Program_Error in one or all of the active partitions involved.

Implementation Permissions

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    An implementation may allow multiple active or passive partitions to be configured on a single processing node, and multiple passive partitions to be configured on a single storage node. In these cases, the scheduling policies, treatment of priorities, and management of shared resources between these partitions are implementation defined.
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    An implementation may allow separate copies of an active partition to be configured on different processing nodes, and to provide appropriate interactions between the copies to present a consistent state of the partition to other active partitions.
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    In an implementation, the partitions of a distributed program need not be loaded and elaborated all at the same time; they may be loaded and elaborated one at a time over an extended period of time. An implementation may provide facilities to abort and reload a partition during the execution of a distributed program.
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    An implementation may allow the state of some of the partitions of a distributed program to persist while other partitions of the program terminate and are later reinvoked.
NOTES
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3  Library units are grouped into partitions after compile time, but before run time. At compile time, only the relevant library unit properties are identified using categorization pragmas.
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4  The value returned by the Partition_ID attribute can be used as a parameter to implementation-provided subprograms in order to query information about the partition.

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