Date: Thu, 13 May 1999 17:06:38 -0700 (PWT) From: Matthew Jacob <mjacob@feral.com> To: Gerard Roudier <groudier@club-internet.fr> Cc: Chuck Robey <chuckr@picnic.mat.net>, freebsd-scsi@FreeBSD.ORG Subject: Re: IBM scsi drives Message-ID: <Pine.LNX.4.04.9905131706140.28716-100000@feral.com> In-Reply-To: <Pine.LNX.3.95.990514003338.2593A-100000@localhost>
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> > > > Yes, I agree. But systems and f/w don't always do the right thing. > > > > Suns enable sync mode first, and then enable wide. IBM Drive accepts the > > wide and chokes. It's not that it goes back to Async. It just chokes. > > (Just guessing about the reasons of the correponding clause in the specs) > The reason of Wide forcing back to Async may be due to the fact that > doubling the BUS width just doubles the data speed and requires twice more > bytes for the offset. For these reasons, a device may elect to negotiate > different period/offset value for SDTR depending on the current agreement > on BUS width. > > On the other hand, SPI-2 says _explicitely_ that WIDE must be negotiated > prior to SYNC and SCSI-2 was also clear about WIDE forcing ASYNC. What you > report is properly unbeleivable, unless Sun guys that maintain Sun's SCSI > stuff are absolute morons. But, may-be, they just donnot want to fix their > stuff. Result of such important vendor not conforming to the specs may > encourage SCSI device manufacturers to sell non compliant devices that may > defeat compliant drivers and controllers. It is properly unacceptable. As a former Sun employee, I'll agree with some of this. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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