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Hardware Supported Protection Mechanism in Message Passing Multicomputers

IP.com Disclosure Number: IPCOM000103803D
Original Publication Date: 1993-Jan-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 1 page(s) / 56K

Publishing Venue

IBM

Related People

Snir, M: AUTHOR

Abstract

Disclosed is a scheme for detecting traffic that crosses protection boundaries in a multiprocessor that has been partitioned into several partitions, each dedicated to a distinct job. A Partition Register (PR) is implemented in the network adapter which is used for interprocessor communication. The register is protected so that its content can be modified only by kernel code. Each outgoing message is tagged by the content of this register; the tag of each incoming message is compared to the receiver PR; a mismatch results in an exception. This simple scheme will guarantee that all messages generated within a partition and sent to another processor in the partition will be received with no exception, whereas any message crossing a partition boundary will generate an exception.

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Hardware Supported Protection Mechanism in Message Passing Multicomputers

      Disclosed is a scheme for detecting traffic that crosses
protection boundaries in a multiprocessor that has been partitioned
into several partitions, each dedicated to a distinct job.  A
Partition Register (PR) is implemented in the network adapter which
is used for interprocessor communication.  The register is protected
so that its content can be modified only by kernel code.  Each
outgoing message is tagged by the content of this register; the tag
of each incoming message is compared to the receiver PR; a mismatch
results in an exception.  This simple scheme will guarantee that all
messages generated within a partition and sent to another processor
in the partition will be received with no exception, whereas any
message crossing a partition boundary will generate an exception.

      The scheme can be generalized in several ways.

      A special, don't care value can be used to tag messages from
trusted service nodes.  They will accept messages from any partition,
and their message will be accepted by any node. :p.  Vector valued
partition registers can be used to provide for an hierarchy of access
rights.  Consider, for example, three PR values: V1=1...1, V2=01...1,
and V3=X1...1 (X stands for don't care).  Then processors with PR
value V1 can communicate with processors with PR values V1 and V3;
processors with PR value V2 can communicate with processors with PR
values...