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.
Patent No.:
Date of Patent:
May. 09, 1995
Filed:
Apr. 06, 1990
Larry P Henson, Santa Clara, CA (US);
Kumar Gajjar, San Jose, CA (US);
Thomas E Idleman, Santa Clara, CA (US);
MTI Technology Corporation, Anaheim, CA (US);
Abstract
The present invention provides a method and apparatus for dynamically modifying the priority of access to a bus, where the bus has control and arbitration functions distributed among the devices coupled to the bus, with each device having a fixed priority level. Access to the bus by particular devices is selectively inhibited, preventing them from asserting their fixed priority level. In a preferred embodiment, the present invention provides control over the reselection of a SCSI bus by a plurality of SCSI devices coupled to the bus by providing a pseudo busy signal to SCSI devices from which reselection is not desired. In this fashion, an initiator may issue a plurality of commands to the SCSI devices and control the order in which the devices will be serviced when ready. A plurality of pseudo busy circuits are provided, with one coupled to each device on the bus. Each pseudo busy circuit is controlled by a control signal from the initiator. The pseudo busy circuit intercepts the busy line of the SCSI bus and provides a pseudo busy signal to the busy line input of the device when instructed by the initiator; although this requires additional control lines in conjunction with the SCSI bus, it allows the use of standard peripherals connectors and controllers designed for the SCSI bus.