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Dynamic SCSI bus domain validation

IP.com Disclosure Number: IPCOM000013389D
Original Publication Date: 2000-Feb-01
Included in the Prior Art Database: 2003-Jun-18
Document File: 1 page(s) / 37K

Publishing Venue

IBM

Abstract

Dynamic SCSI Bus Domain Validation

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Dynamic SCSI bus domain validation

Dynamic SCSI Bus Domain Validation

Disclosed is a method for performing run-time domain validation for Small Computer Systems Interface (SCSI) busses. Domain Validation as defined in the SCSI Parallel Interface-3 (SPI-3) specification is a process that is intended to be run before normal operations are started to ensure the suitability of the SCSI channel at the configured data transfer speed. This method of determining SCSI channel capability should be helpful in determining the capability of the channel at the start of the I/O process. However, domain validation test is very limited in the data patterns that can be run and still allow the system to restart the SCSI channel in a reasonable period of time. For the purposes of this discussion, this method of validation is referred to as Static Domain Validation.

The new proposal is to dynamically or continuously validate the SCSI domain by reducing the operating speed of the bus or change the SCSI data transfer mode (from Dual-Transition clocking to Single-Transition clocking) based on the detection of recoverable and unrecoverable SCSI bus errors. If a SCSI channel communications error is detected (such as a SCSI parity/CRC error, bus hang, phase error, data byte count mis-match, unexpected third party bus reset, or unexpected bus free) the bus speed is reduced according to a pre-defined speed reduction matrix. The reduction of speed or switching from Dual-Transition clocking to...