Browse Prior Art Database

Fault-Tolerant Bus Terminator for Concurrent Maintenance

IP.com Disclosure Number: IPCOM000104973D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 4 page(s) / 96K

Publishing Venue

IBM

Related People

Rasmus, TM: AUTHOR [+4]

Abstract

Disclosed is a fault tolerant bus termination scheme which provides the ability to perform concurrent maintenance. In other words, a failing section of the bus termination can be removed and replaced without disrupting the operation of the backplane.

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

Fault-Tolerant Bus Terminator for Concurrent Maintenance

      Disclosed is a fault tolerant bus termination scheme which
provides the ability to perform concurrent maintenance.  In other
words, a failing section of the bus termination can be removed and
replaced without disrupting the operation of the backplane.

      Fig. 1 shows a backpanel bus with multiple card slots that
accept some type of pluggable function card (i.e., CPU, I/O, Memory,
etc.).  It is assumed the adapter bus interface supports redundancy
(i.e., duplicate address, data, control signals) or some form of bus
folding.  A packet- type bus has duplicate control signals and a set
of data lines.  If a fault occurs on the data lines, the bus is
folded (half of the data lines are used and the bus bandwidth drops
accordingly).  The backplane bus is terminated to maintain good
transmission line characteristics by placing a termination network at
each end of the backplane bus.  One of the properties of a backplane
bus is the number of I/O signals tend to increase as the bus
bandwidth increases.  It is not uncommon to have hundreds of I/O
signals in a high performance bus.  Two things happen with the
terminator as the number of bus signals increase.

o   The number of elements, resistors, diodes, and capacitors in the
    termination increase proportionally with the number of bus
    signals.  Therefore, the failure rate also increases.

o   The power requirement for the Thevenin terminator voltage
    increases.  As power dissipation increases, the localized
    temperature may increase and affect the reliability of the
    network.

      Another item to consider is the use of active termination
(Thevenin voltage supply built into the termination network).  Active
termination designs appear with the increasing popularity of
distributed box power designs (DC/DC converts on board each adapter).
When a DC/DC converter becomes part...