I don't know about the jffs2 internals in detail, but I'm pretty sure that it doesn't work in the way you described. That would be the worst approach for a flash filesystem that one can think of.
-Erwin Am Montag, den 19.10.2009, 17:28 -0700 schrieb Prasad: > For the NOR flash, when the write( , , 1) routine is called, the file > system(jffs2 in this case) has to read back the whole sector, modify > that byte, erase the sector and then write back the whole sector (in > order to write a single byte). Is it not so..So it does affect the > flash-lifetime right? > > - Prasad > > On Mon, Oct 19, 2009 at 5:04 PM, Erwin Authried <ea...@softsys.co.at> wrote: > > for NOR flash, the number of erase cycles on each sector is limited, not > > the number of writes. For the flash lifetime, it doesn't make a > > difference if you write one byte at a time or a complete sector at once. > > > > -Erwin > > > > Am Montag, den 19.10.2009, 16:43 -0700 schrieb Prasad: > >> Interesting..till now i was thinking there is still some kind of > >> buffering mechanism in case of NOR flash. So if there is a process > >> that opens a file writes one byte at a time (write() or fwrite() on > >> jffs2 partitioned file system), this will kind of wear out the flash > >> pretty right?. May be a stupid question, can we force the buffering > >> even for NOR flash for increasing the longevity of the flash ? > >> > >> - Prasad > >> > >> On Mon, Oct 19, 2009 at 12:49 PM, Keith Mund (AZ) <keithm...@cox.net> > >> wrote: > >> >>from Prasad - Monday, October 19, 2009 10:53 AM: > >> >>I mean to ask, is there any advantage in using NOR-ECC flash agains > >> >>regular NOR flash. Does the linux mtd driver/jffs2 differentiate it? > >> > > >> > The "advantage" part depends on the needs of each system. Some benefits > >> > of > >> > ECC are that it helps overcome problems with occasional false flash > >> > reads, > >> > and buffered writing can be faster. Direct write through with NOR > >> > dramatically reduces the chances of corruption due to an interrupted > >> > write. > >> > > >> > Linux does determine if you have NOR-ECC and enables buffering. > >> > Buffering is > >> > a must because you can call the file write function numerous times, even > >> > to > >> > write one byte at a time. NOR-ECC only allows one write per page before > >> > an > >> > erase so the writes are buffered before they are committed. > >> > > >> > Keith Mund > >> > > >> > > >> > _______________________________________________ > >> > uClinux-dev mailing list > >> > uClinux-dev@uclinux.org > >> > http://mailman.uclinux.org/mailman/listinfo/uclinux-dev > >> > This message was resent by uclinux-dev@uclinux.org > >> > To unsubscribe see: > >> > http://mailman.uclinux.org/mailman/options/uclinux-dev > >> > > >> _______________________________________________ > >> uClinux-dev mailing list > >> uClinux-dev@uclinux.org > >> http://mailman.uclinux.org/mailman/listinfo/uclinux-dev > >> This message was resent by uclinux-dev@uclinux.org > >> To unsubscribe see: > >> http://mailman.uclinux.org/mailman/options/uclinux-dev > > > > _______________________________________________ > > uClinux-dev mailing list > > uClinux-dev@uclinux.org > > http://mailman.uclinux.org/mailman/listinfo/uclinux-dev > > This message was resent by uclinux-dev@uclinux.org > > To unsubscribe see: > > http://mailman.uclinux.org/mailman/options/uclinux-dev > > > _______________________________________________ > uClinux-dev mailing list > uClinux-dev@uclinux.org > http://mailman.uclinux.org/mailman/listinfo/uclinux-dev > This message was resent by uclinux-dev@uclinux.org > To unsubscribe see: > http://mailman.uclinux.org/mailman/options/uclinux-dev _______________________________________________ uClinux-dev mailing list uClinux-dev@uclinux.org http://mailman.uclinux.org/mailman/listinfo/uclinux-dev This message was resent by uclinux-dev@uclinux.org To unsubscribe see: http://mailman.uclinux.org/mailman/options/uclinux-dev
