Re: Compute flash life time
From: linnix (me_at_linnix.info-for.us)
Date: 05/19/05
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- In reply to: giangiammy_at_yahoo.com: "Compute flash life time"
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Date: 19 May 2005 07:53:35 -0700
giangiammy@yahoo.com wrote:
> Hi all,
>
> and sorry for the obvious question, but I'm trying to
> estimate my flash life, depending on write operation.
>
> I'm using JFFS2:
> If I have 1 M flash, and write 128byte/s in a circular
> buffer style: I compute, with 100000 write cycles to
> have a 9000 day flash life (100000 * 1024*1024/128 seconds).
>
> But in this way I suppose that each 128 blob of data
> I write, effectively write 128 bytes of flash: but
> I'm trying to understand:
>
> - what is the filesystem overhead?
> - when I write 128 bytes, the filesystem writes effectively
> 128 bytes, or writes an entire sector?
The file system writes a sector of 512 bytes, but the flash erase
and write a cluster of 1024, 2048, 4096 or 8192 bytes. Cluster sizes
are higher for bigger flash. For 1M, I believe it's 1024, or approx.
100 days.
> - to do my computation, is it correct the formula I used,
> or do I need to substitute the 128 value with the flash
> sector size?
Yes, see http://cfd.linnix.com/mtbf.html
>
> Sorry if the questions are obvious, but I'm almost new to JFFS2
>
> thanks
> giammy
- Previous message: collinm: "memory leak tool..."
- In reply to: giangiammy_at_yahoo.com: "Compute flash life time"
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