(12) United States Patent ao) Patent No.: us 6,820,165 B2
Pannell (45) Date of Patent: Nov. 16,2004
(54) SYSTEM AND METHOD FOR INCREASING THE COUNT OF OUTSTANDING SPLIT TRANSACTIONS
(75) Inventor: Roger D. Pannell, Nashua, NH (US)
(73) Assignee: Hewlett-Packard Development
Company, L.P., Houston, TX (US)
( * ) Notice: Subject to any disclaimer, the term ol this patent is extended or adjusted under 35 U.S.C. 154(b) by 481 days.
(21) Appl. No.: 09/944,517
(22) Filed: Aug. 31, 2001
(65) Prior Publication Data
US 2002/0083256 Al Jun. 27, 2002
Related U.S. Application Data
(60) Provisional application No. 60/229,830, filed on Aug. 31, 2000, and provisional application No. 60/304,167, filed on Aug. 31, 2000.
(51) Int. CI.7 G06F 13/00
(52) U.S. CI 710/313; 710/310; 710/311
(58) Field of Search 710/305, 306,
710/310, 311, 313, 314
(56) References Cited
U.S. PATENT DOCUMENTS
5,535,345 A 7/1996 Fisch et al.
5,553,310 A 9/1996 Taylor et al.
5,594,882 A 1/1997 Bell
6,098,134 A 8/2000 Michels et al.
6,425,024 Bl * 7/2002 Kelley et al 710/56
6.523.140 Bl * 2/2003 Arndt et al 714/44
6.581.141 Bl * 6/2003 Kelley et al 711/154
PCI-X Addendum to the PCI Local Bus Specification, Revision 1.0, PCI Local Bus, Sep. 22, 1999, pp. 1-222. PCI-X Addendum to the PCI Local Bus Specification, PCI Local Bus, Revision 1.0, Sep. 22, 1999, pp. 1-21, 34-39, 44-50, 58-62 and 78-84.
* cited by examiner
Primary Examiner—Glenn A. Auve (57) ABSTRACT
A system and method increases the number ol split transactions that can be outstanding on an input/output (I/O) bus operating in accordance with a bus protocol, such as the Peripheral Component Interlace Extended (PCI-X) specification standard. An I/O bridge that interlaces between one or more processors and one or more I/O devices coupled to the I/O bus includes a transaction initiation engine, a transaction completion engine and one or more queues for buffering information that is to be translerred onto or which has been received from the I/O bus. The I/O bridge is configured to concatenate, at least logically, a tag field and a lunction number field from an attribute message so as create a novel, super-tag field that the I/O bridge then associates with each bus transaction. By creating the super-tag field, the I/O bridge substantially increases the number ol uniquely identified bus transactions which may be responded to with a Split Response.
15 Claims, 7 Drawing Sheets