From owner-freebsd-hackers Fri Sep 22 23:26: 6 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from homer.softweyr.com (bsdconspiracy.net [208.187.122.220]) by hub.freebsd.org (Postfix) with ESMTP id 1006337B43E for ; Fri, 22 Sep 2000 23:25:50 -0700 (PDT) Received: from localhost ([127.0.0.1] helo=softweyr.com ident=Fools trust ident!) by homer.softweyr.com with esmtp (Exim 3.16 #1) id 13ci4j-0000Sb-00; Fri, 22 Sep 2000 23:42:13 -0600 Message-ID: <39CC42B5.42FB21FD@softweyr.com> Date: Fri, 22 Sep 2000 23:42:13 -0600 From: Wes Peters Organization: Softweyr LLC X-Mailer: Mozilla 4.75 [en] (X11; U; FreeBSD 4.1-STABLE i386) X-Accept-Language: en MIME-Version: 1.0 To: Warner Losh Cc: Douglas Swarin , freebsd-hackers@FreeBSD.ORG, kkemp@nwcr.net Subject: Re: Frustration with SCSI system References: <20000921182405.A82919@staff.texas.net> <20000920125128.F9141@fw.wintelcom.net> <200009212344.RAA63251@harmony.village.org> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Warner Losh wrote: > > In message <20000921182405.A82919@staff.texas.net> Douglas Swarin writes: > : Ideally, I would use one of the IDE flash-based drives on the market. One > : brand is SanDisk, and they take a standard IDE connector and fit into a > : 3.5" drive bay. You can get them very reasonably priced up to 128MB or > : so, which is just fine for a boot partition. Since flash drives have no > : moving parts, mechanical failure is not an issue, and since the root > : partition is not written to much, the flash will not wear out for a > : long time (flash cells wear out after about 100,000 writes; the flash > : drives do load balancing and stuff to ensure that the (many) cells in > : the drive are written to evenly). > > We use these devices heavily at Timing Solutions. Or rather we use > a IDE <-> CF adapter and haven't had any devices wear out. And some > of these devices have had rather heavy use. I think that it is closer > to 1 million writes per cell, but I don't have my spec sheets handy. The newer devices do 1 million writes per cell. When I left Xylan earlier this year, some of our early (late '94 or early '95) flash devices were just beginning to fail. These were development machines that saw a lot of write cycles, and their home-grown flash filesystem does a pessimal job of rewriting the same cells over and over again. > Are you sure that they do write balancing? The indications I have > from the base chip technology is that they don't. I could have missed > that in the data sheets. It has been a little while since I looked at > them, so I might be misremembering. I can't seem to find the data > sheets I looked at before. SanDisk does, in the controller chip. Good technology. -- "Where am I, and what am I doing in this handbasket?" Wes Peters Softweyr LLC wes@softweyr.com http://softweyr.com/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message