Date: Fri, 22 Sep 2000 16:18:05 +0200 (CEST) From: Marius Bendiksen <mbendiks@eunet.no> To: Mike Smith <msmith@FreeBSD.ORG> Cc: freeBSD-scsi@FreeBSD.ORG Subject: Re: disable write caching with softupdates? Message-ID: <Pine.BSF.4.05.10009221614370.48894-100000@login-1.eunet.no> In-Reply-To: <200009211932.MAA01341@mass.osd.bsdi.com>
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> Not really. You link "real" geometries with "all the stuff FFS does to > exploit it". FFS' attempts to "exploit" drive geometry are intentionally > disabled because they don't work. As was pointed out by another poster, > unless you have a good drive access model in the time domain, these > optimisations are typically pessimisations anyway. This fault was ceded in a later post, as I recall. FFS currently does not handle sufficiently complex geometric parameters that exposing the real ones would make an improvement. I do think it likely that someone would step forth and implement this properly, though, if an interface should become available to obtain such information, and, if we had realtime ability with fine grained timing. > > And this still relies on having the drive provide the correct information, > > including such things as temperature, air moisture levels, or whatever. > > This, as you pointed out, is not reported by disk drives. > > I think ultimately we're in more or less violent agreement. 8) Highly likely. Let's not get further into this. I will, and have, ceded the point that there are other optimizations that take precedence over the geometric ones. Marius To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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