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Browse Prior Art Database

Semi-Dynamic Distributed Data Managing Table for Distributed Shared Memory

IP.com Disclosure Number: IPCOM000112451D
Original Publication Date: 1994-May-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 4 page(s) / 150K

Publishing Venue

IBM

Related People

Fukuda, M: AUTHOR [+2]

Abstract

Disclosed is a mechanism to manage the data location efficiently, on the Distributed Shared Memory (DSM) system on which the data aren't fixed at their initial locations, and move from a node to a next.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Semi-Dynamic Distributed Data Managing Table for Distributed Shared
Memory

      Disclosed is a  mechanism to manage the data  location
efficiently, on the Distributed Shared Memory (DSM) system on which
the data aren't fixed at their initial locations, and move from a
node to a next.

      The mechanism is added into each computer node's communication
adapter, in  the large  scale loosely  coupled multiprocessor
system, connected with  high-speed communication  media (Fig. 1).  It
is also applied to  the software  implemented DSM  system.   The
mechanism  is realized with two data management tables.

      One is the  dynamic directory table.  Each computer  node has
the dynamic directory table  corresponding to its own local  memory.
This table  manages  two suits  of  information:   the  memory
consistency information of the data now located in its local memory,
and the owner location information of the data whose  entity is no
longer located in its local  memory.  The owner  location information
of the  data which have already been  invalidated is kept until  a
new data is  mapped on the same location.  The owner location of the
data accessed frequently can usually be obtained through its own
dynamic directory table.

      The other is the fixed owner table.  Each computer node has the
fixed owner table  corresponding to the capacity of  its local
memory.  This table manages the owner location information of the
data assigned to the node.  The fixed owner table of each node is
assigned a part of the distributed shared  memory space corresponding
to the capacity of its local memory.   For a specified DSM address,
a node which has the corresponding fixed  manager table entry is
called a 'manager'.   The fixed  owner table  answers  to the
inquiry  from  a processor  which accesses the  data hasn't  been
accessed  or the  data whose  location information has been lost from
its dynamic directory table.  The dynamic directory table's entries
consist of the following items:

1.  DSM data unit number(address)

2.  Valid flag: indicator of whether the data unit is valid

3.  Local memory data unit number: the data unit number assigned
    locally.

4.  Owner: the node number of the node writable to this data unit.

5.  Sh...