Compute flash life time

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?

- 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?

Sorry if the questions are obvious, but I'm almost new to JFFS2

thanks giammy