Browse Prior Art Database

Dual Processor Design Using Gast Dual Port Scram

IP.com Disclosure Number: IPCOM000111337D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 4 page(s) / 96K

Publishing Venue

IBM

Related People

Chan, JC: AUTHOR [+2]

Abstract

A communication mechanism is designed to allow two IBM RS/6000* Rios 2 processors to communicate locally by using the SIO_Bus. From this, a deskside server with dual processors can be developed. The results indicate that the design can improve the overall system performance significantly, and can have applications to high availability computations.

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Dual Processor Design Using Gast Dual Port Scram

      A communication mechanism is designed to allow two IBM RS/6000*
Rios 2 processors to communicate locally by using the SIO_Bus.  From
this, a deskside server with dual processors can be developed.  The
results indicate that the design can improve the overall system
performance significantly, and can have applications to high
availability computations.

      Solution - Implement a dual port RAM on the SIO buses of two
Rios 2 processors.  Messages may be passed between these processors
via a special AIX device driver.  This device would run synchronous
to each SIO bus, buffering the data.

      Design Configuration - Two independent machines (CPU+MEM),
designed and packaged in one Deskside Product box.  The dual RS2G
communicate via the SIO_Bus (shared IO resources, e.g., DASD).  This
is shown the Figure.

      Communication Protocol - Referring to the Figure, the
communication between the two processors is via the dual port SRAM,
which serves as a buffer to the data transfer on the SIO-Bus.  The
design is according to the specification of the SIO-Bus, and is
described as follows:

Communication Protocol (READ):

MCM1 issues IO Load, then switch to another task.
PAL generates DMA Read request to MCM2.
MCM2 SIO_Bus is granted.
DMA Read via MCM2 SIO_Bus (data are buffered in SRAM).
PAL issues request for SIO_Bus of MCM 1.
MCM 1 SIO_Bus granted.
Data   transfer.

Communication Protocol (Write):

MCM 1 issues IO Store ( data are buffered in SRAM).
PAL issues DMA Write to MCM2.
MCM2 SIO_Bus granted.
Data  transfer.

      Advantages - The dual server could be configured three
different ways.  First, each server could be independent of each
other.  The 2 processors would share the same DASD, and storage
devices.  Multi-user applications, like databases, would enjoy faster
throughput by not having to send data over a local area ring.  The
Advantages are:

      Faster communication protocol (local).  Better performance than
any 601 base processor.  Not a parallel system, software burden is a
lot smaller.  Example of Competitor Offering: HP/TI 5108 (Dual
Processor...