From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail1.daniel.com ([12.19.96.6] helo=mail1.danielind.com) by pentafluge.infradead.org with esmtp (Exim 3.22 #1 (Red Hat Linux)) id 16RMuO-00005G-00 for ; Fri, 18 Jan 2002 00:29:28 +0000 Message-ID: <3C474523.60E74892@daniel.com> Date: Thu, 17 Jan 2002 15:41:55 -0600 From: Vipin Malik MIME-Version: 1.0 To: Herman Oosthuysen CC: dennis noermann , linux-mtd@lists.infradead.org Subject: Re: experience with max block erase References: <002101c19f99$874d7e60$0100007f@localdomain.wni.com.wirelessnetworksinc.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-mtd-admin@lists.infradead.org Errors-To: linux-mtd-admin@lists.infradead.org List-Help: List-Post: List-Subscribe: , List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: Herman Oosthuysen wrote: > 100 000 cycles is lot. You have to erase the chip about ten times per hour > continuously for 100 years to reach that number... Let's state 100K cycles another way: for a 8mbit chip (1024KB) It's only 100K * 1024KB of data life (assuming a circular use- which is the best case and what you will get with wear leveling). If you want your product to last 8 years (pick a number), then the max data rate that you can send to the flash chip is "only": 100000 * 1024/(8*365*24*60*60) = 0.4KB/sec! That's not a lot. This does not even take into account the extra data generated due to the overhead of any filesystem one may be using. Tack in another 20% for that (not unusual for JFFS2 system- it depends on write sizes- this assumes a small write size/write) then the data rate falls to 0.32KB/sec OR let's say that the system is generating data (that needs to be saved to flash) at the rate of 10KB/sec (not very high number too), then the life of the system is only 0.32years! (Yikes!) Vipin