From owner-freebsd-hackers@FreeBSD.ORG Sun Aug 21 00:34:28 2005 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9439316A41F for ; Sun, 21 Aug 2005 00:34:28 +0000 (GMT) (envelope-from hselasky@c2i.net) Received: from swip.net (mailfe04.swip.net [212.247.154.97]) by mx1.FreeBSD.org (Postfix) with ESMTP id 08A9643D46 for ; Sun, 21 Aug 2005 00:34:27 +0000 (GMT) (envelope-from hselasky@c2i.net) X-T2-Posting-ID: Y1QAsIk9O44SO+J/q9KNyQ== Received: from mp-217-204-116.daxnet.no ([193.217.204.116] verified) by mailfe04.swip.net (CommuniGate Pro SMTP 4.3.4) with ESMTP id 445139323 for freebsd-hackers@freebsd.org; Sun, 21 Aug 2005 02:34:25 +0200 From: Hans Petter Selasky To: freebsd-hackers@freebsd.org Date: Sun, 21 Aug 2005 02:35:16 +0200 User-Agent: KMail/1.7 References: <200508200359.j7K3xoHF015718@ambrisko.com> <200508201230.37976.hselasky@c2i.net> <20050820.171238.122195775.imp@bsdimp.com> In-Reply-To: <20050820.171238.122195775.imp@bsdimp.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200508210235.17608.hselasky@c2i.net> Subject: Re: Parking disk drive heads X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: hselasky@c2i.net List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 21 Aug 2005 00:34:28 -0000 On Sunday 21 August 2005 01:12, M. Warner Losh wrote: > In message: <200508201230.37976.hselasky@c2i.net> > > Hans Petter Selasky writes: > : On Saturday 20 August 2005 10:18, Mike Silbersack wrote: > : > On Fri, 19 Aug 2005, Doug Ambrisko wrote: > : > > Flash is nice but it has some issues. Atleast dropping it isn't one! > : > > > : > > Doug A. > : > > : > I'd be really happy if I could get a USB flash drive to last more than > : > 8 months. Luckily, I started weekly backups after the first failure. > : > That helped a lot when the second failure happened. > : > : Flash drives does usually not last more than 10000 writes, per bit, from > : what I know. Probably you need some kind of special file-system that > : moves the files around as the write quoute gets used up! Eventually the > : size of the disk will reach zero, and you have to move the files > : elsewhere :-) But this is probably off topic. > > Actually, 10,000 writes per bit is one or two orders of magnitude too > low these days. It was more typical for the Linear Flash PCMCIA cards > from 10 years ago. Today, typically flash devices are good for more > like 100,000 or 500,000 writes per cell, and all the fobs you'd buy > these days have built-in wear averaging. I've tried three times now > to wear out a flash by writing an incrementing counter to a single > location only to give up after weeks of hammering due to external > factors (power failure, network failure, etc). Are you sure that the flash drive is not caching the writes in RAM? --HPS