Messages in this thread | | | Subject | Re: swap file over jffs2 partition | From | Bernd Petrovitsch <> | Date | Mon, 03 Mar 2008 15:19:09 +0100 |
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On Mon, 2008-03-03 at 00:27 +1030, David Newall wrote: > Bernd Petrovitsch wrote: > > The wear-levelling only makes all erase blocks/chunks/... wear out at > > the same rate (at least more or less). It doesn't avoid or reduce > > wearing out, it just distributes it. > > Surely a unit with one defective block and a squillion good blocks is > faulty. Sure it is. It has a fault, which is what it means to be
Several are very probably faulty as NAND flashes initially already have bad blocks (but there a re some more on that chip to compensate for that). Even if just 1 of a squillion (erase-)blocks is gone. But that's now and only the first. More to follow sooner or later ..... I don't think that "writing to swap space" is in any way limited or minimized but assumes normal harddisks. So it is not like you are writing to the flash chip only on "save in some UI or on a firmware update.
> faulty. Spread the wear of that one block over all squillion and one > blocks and you get a much longer lifetime. It seems intuitive that > distributing wear significantly increases time to failure.
Yes, that's the idea. Nevertheless it places "load" on the flash chips.
Actually I'm curious how fats it is and how well it works (and with which flash chips exactly) if one simply tries it out. If it actually works.
Bernd -- Firmix Software GmbH http://www.firmix.at/ mobil: +43 664 4416156 fax: +43 1 7890849-55 Embedded Linux Development and Services
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