From owner-freebsd-scsi Fri Jun 20 01:39:02 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id BAA21083 for freebsd-scsi-outgoing; Fri, 20 Jun 1997 01:39:02 -0700 (PDT) Received: from sendero-ppp.i-connect.net (sendero-ppp.i-Connect.Net [206.190.143.100]) by hub.freebsd.org (8.8.5/8.8.5) with SMTP id BAA21077 for ; Fri, 20 Jun 1997 01:38:58 -0700 (PDT) Received: (qmail 7894 invoked by uid 1000); 20 Jun 1997 08:39:05 -0000 Message-ID: X-Mailer: XFMail 1.2-alpha [p0] on FreeBSD Content-Type: text/plain; charset=iso-8859-8 Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <199706200304.VAA02058@pluto.plutotech.com> Date: Fri, 20 Jun 1997 01:39:04 -0700 (PDT) Organization: Atlas Telecom From: Simon Shapiro To: "Justin T. Gibbs" Subject: Re: Announcement: New DPT RAID Controller Driver Available Cc: FREEBSD-HACKERS , FREEBSD-SCSI , Brian Tao Sender: owner-freebsd-scsi@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk Hi "Justin T. Gibbs"; On 20-Jun-97 you wrote: > >An excellent mechanical engineer designed a wonderful metal system (both > >canisters and carriers). We had up to 30% perofrmance loss on random > >seeks with system. It baffled anyone until another engineer decided to > >test the drives on his desk, outside the box, outside the carriers - > >Yes, the performance was back. Turns out soft errors were masked and > >the rigid but ringing-resonating nature of steel and the high packing > >density caused drives to resonate the cabinets and cause miseeks. > > Pluto's drive sled design uses a very simple and cheap suspension design > to deal with this very problem. Proof that this problem is not unique. There are several ways of dealing with it. Worse was hanging devices on... springs! Simon