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Browse Prior Art Database

Fault-Tolerant Mechanism for Addressing Faults on a Failing Bus

IP.com Disclosure Number: IPCOM000115340D
Original Publication Date: 1995-Apr-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 4 page(s) / 76K

Publishing Venue

IBM

Related People

Downes, RW: AUTHOR [+6]

Abstract

A technique is presented that provides single fault-detection on bus structures that are not architected to provide a high degree of fault tolerance.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 58% of the total text.

Fault-Tolerant Mechanism for Addressing Faults on a Failing Bus

      A technique is presented that provides single fault-detection
on bus structures that are not architected to provide a high degree
of fault tolerance.

      This invention is not limited to multi-point connections or
serial busses.  However, for purposes of illustration, a serial bus
using multi-point connection will be used.  Specifically, the I sup 2
C* Bus will be used.  The connected elements are Field Replaceable
Units (FRUs).  On each FRU is an I sup 2 C Expander Module and an
Electrically Erasable Read Only Memory (EEPROM).  The expander module
has eight ports.  A port can be used to provide either input sense
data or output control.  In this example, one port is used to control
the selection of the EEPROM.  The EEPROM, a random access memory,
holds FRU Vital Product Data (VPD) and error log data.

      The invention makes use of a NULL bus address.  A NULL address
is defined to be an address that is NOT used within the system.  If
the NULL address were used and there were no failures, there should
be no action (response) by any FRU.  If a failing FRU acts as though
it is addressed (selected),  an action by this FRU will be taken.
With proper control and monitoring mechanisms, the unexpected action
will be detected by the addresser.

      Additionally, a method of identifying the element that has a
bus addressing fault is needed.  In the preferred embodiment, the
meth...