The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Nov. 16, 1999

Filed:

Nov. 05, 1997
Applicant:
Inventors:

Charles Monia, Marlboro, MA (US);

Fee Lee, Framingham, MA (US);

William Ham, Andover, MA (US);

Assignee:

Digital Equipment Corporation, Houston, TX (US);

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F / ;
U.S. Cl.
CPC ...
710240 ; 710128 ; 710120 ; 710112 ; 710113 ;
Abstract

A SCSI bus extender apparatus coupling a primary SCSI bus to a secondary SCSI bus includes a mechanism for detecting and resolving contention between a substantially simultaneous SELECTION operation on the primary bus and a RESELECTION operation on the secondary bus. The inventive method contemplates the bus extender arbitrating for control of the primary bus after a conflict is detected, and releasing control of the secondary bus if control of the primary bus is obtained. A target device on the secondary bus can then rearbitrate for control of the secondary bus. Once the target device controls the secondary bus, it can direct a RESELECTION signal to the bus extender, which responsively directs the signal to an initiator device on the primary bus. If the bus extender is unable to gain control of the primary bus after a conflict is detected, the SELECTION operation is allowed to proceed and the target device reattempts to assert the RESELECTION operation thereafter.


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