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From: Vipin Malik <vipin.malik@daniel.com>
To: Herman Oosthuysen <Herman@WirelessNetworksInc.com>
Cc: dennis noermann <dennis.noermann@noernet.de>,
	linux-mtd@lists.infradead.org
Subject: Re: experience with max block erase
Date: Thu, 17 Jan 2002 15:41:55 -0600	[thread overview]
Message-ID: <3C474523.60E74892@daniel.com> (raw)
In-Reply-To: 002101c19f99$874d7e60$0100007f@localdomain.wni.com.wirelessnetworksinc.com

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

  reply	other threads:[~2002-01-18  0:29 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-01-17  0:50 experience with max block erase dennis noermann
2002-01-17 16:29 ` Vipin Malik
2002-01-17 20:56 ` Herman Oosthuysen
2002-01-17 21:41   ` Vipin Malik [this message]
2002-01-18 16:09     ` Herman Oosthuysen
     [not found] <135138262.1011228859807.JavaMail.root@boots>
2002-01-17 18:16 ` Cam Mayor

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