From owner-freebsd-chat Wed Aug 16 0:11:29 2000 Delivered-To: freebsd-chat@freebsd.org Received: from netplex.com.au (adsl-63-207-30-186.dsl.snfc21.pacbell.net [63.207.30.186]) by hub.freebsd.org (Postfix) with ESMTP id A954437C17C for ; Wed, 16 Aug 2000 00:11:19 -0700 (PDT) (envelope-from peter@netplex.com.au) Received: from netplex.com.au (peter@localhost [127.0.0.1]) by netplex.com.au (8.9.3/8.9.3) with ESMTP id AAA18408; Wed, 16 Aug 2000 00:09:40 -0700 (PDT) (envelope-from peter@netplex.com.au) Message-Id: <200008160709.AAA18408@netplex.com.au> X-Mailer: exmh version 2.1.1 10/15/1999 To: David Scheidt Cc: Terry Lambert , fran@reyes.somos.net, "Nicole Harrington." , "(Mike Tancsa)" , "chat@FreeBSD.ORG" Subject: Re: 3ware IDE Raid. SCSI killer? In-Reply-To: Date: Wed, 16 Aug 2000 00:09:40 -0700 From: Peter Wemm Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org David Scheidt wrote: > (cc's snipped.) > On Tue, 15 Aug 2000, Terry Lambert wrote: > > :> On Sat, 12 Aug 2000 00:09:34 +0000 (GMT), Terry Lambert wrote: > :> >...as a backhand reference to the fact that IDE dtill does not > :> >support concurrent outstanding I/O via tagged command queueing. > :> > :> I could be wrong, but I though I read some reference to tagged > :> queing on the 3ware site. > : > :The standard supports it. No one implements it in any drives. > : > > I've been led to believe this is because if they did, the disks would cost > almost as much as SCSI disks. The only thing IDE has going for it is that > it's cheap. No, it is only a software change. It costs no difference at all to manufacture and ship an IDE disk with tagged queueing implemented. All it needs is a once-off investment in programmer time for an almost trivial task compared to the other stuff that the firmware has to do. Cheers, -Peter -- Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message