Browse Prior Art Database

Performance-Upgrade of Data-Busses by Operation-Interleaving

IP.com Disclosure Number: IPCOM000114125D
Original Publication Date: 1994-Nov-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 74K

Publishing Venue

IBM

Related People

Goldrian, G: AUTHOR [+3]

Abstract

The need for more data-throughput on an existing computer I/O-bus can be attained in some cases by the introduction of "Operation-interleaving". This method interleaves operations during the otherwise idling times on the bus (Idle gaps). A typical idle-gap is the wait-phase for data in a fetch-operation between the sending of the memory request-command and the arrival of the requested data. In store-operations there is often a gap between the last data send to memory and the arrival of the storage-status.

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Performance-Upgrade of Data-Busses by Operation-Interleaving

      The need for more data-throughput on an existing computer
I/O-bus can be attained in some cases by the introduction of
"Operation-interleaving".  This method interleaves operations during
the otherwise idling times on the bus (Idle gaps).  A typical
idle-gap is the wait-phase for data in a fetch-operation between the
sending of the memory request-command and the arrival of the
requested data.  In store-operations there is often a gap between the
last data send to memory and the arrival of the storage-status.

      Making use of such gaps for other operations is known as
interleaving and is used in several applications.  Here, an easy
method is depicted for the upgrading of an existing I/O bus by the
incorporation of interleaving for higher bandwidth, without the
necessity to change any of the existing I/O-bus adapter-cards.  Only
the bus-controller-card has to be replaced by a more powerful one,
and some wiring on the bus requires minor changes.  This
upgrade-method is helpful and makes sense in many cases, especially
when doing the so-called "upgrade" of an existing computer into a
more powerful version.

      First, the method needs to split the arbitration of the
existing bus into two halves which occurs inside the new
bus-controller-card.  Target is to allow a secondary Bus-Unit
(BU-card) via arbitration-grant to use the bus during an idle-gap of
a "primary" operation.  The Bus-Units are not aware of the above
interleaving.  The result of this partitioning into two halves is
limited by nature insofar as operations from BUs on one half can only
be interleaved by operations from BUs resident on the other
arbitration half.  But, this...