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US007409448B2
(12) United States Patent ao) Patent No.: Us 7,409,448 B2
Frazier et al. (45) Date of Patent: Aug. 5,2008
(54) METHOD, SYSTEM, AND STORAGE
MEDIUM FOR RESOLVING CONTENTION
ISSUES DURING CHANNEL PROGRAM
EXECUTION
(75) Inventors: Giles R. Frazier, Austin, TX (US);
Robert J. Dugan, Hyde Park, NY (US)
(73) Assignee: International Business Machines Corporation, Armonk, NY (US)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 937 days.
(21) Appl.No.: 10/723,409
(22) Filed: Nov. 25, 2003
(65) Prior Publication Data
US 2005/0198254 Al Sep. 8, 2005
(51) Int. CI.
G06F15/173 (2006.01)
H04J 3/02 (2006.01)
(52) U.S. CI 709/225; 370/462
(58) Field of Classification Search 709/225;
370/462
See application file for complete search history. (56) References Cited
U.S. PATENT DOCUMENTS 5,465,355 A 11/1995 Cooketal 710/38
An exemplary embodiment of the invention relates to a method, system, and storage medium for resolving contention issues by a channel in a fiber optic switch environment that occur during channel program execution. The method comprises a channel receiving a status packet indicating a device is no longer busy. The method also includes specifying whether the channel intends to re-initiate a channel program that previously resulted in the device busy status. If the channel does not intend to re-initiate the channel program, a first combination of bits in a re-initiate field of a status-acceptance packet are set which indicate that the channel will take no further action. If the channel intends to re-initiate the channel program, a second combination of bits in the re-initiate field of the status-acceptance packet are set, indicating that the channel will re-initiate the channel program. The method further includes transmitting the status-acceptance packet to a control unit. The invention also includes a system and a storage medium.
7 Claims, 3 Drawing Sheets
