On Wed, 2005-09-28 at 20:24 +0200, Marc Schiffbauer wrote: > * Alan Stern schrieb am 28.09.05 um 18:58 Uhr: > > On Wed, 28 Sep 2005, Marc Schiffbauer wrote: > > > > > Hi all, > > > > > > I have an usb-storage device in my Computer hat can handle several > > > memory-cards like CF, SD, MMC, MS and SM Cards. > > > > > > I often read/write to my 1 gig SD card (USB 2.0). Reading is always > > > fast (~ 5MB/s) using Kernel 2.6.12 or 2.6.13. > > > > > > But: Writing to the card is very very slow: < 40 kb/s. > > > > > > My kubuntu system mounts that kind of devices like that: > > > /dev/sda1 on /media/sda1 type vfat > > > > > > (rw,noexec,nosuid,nodev,sync,quiet,uid=1000,gid=1000,umask=077,iocharset=utf8) > > > > > > Now I discovered that if I do a "mount -o remount,async /meda/sda1", > > > the writing speed increases to a normal value of about 5 megs/s. > > > > > > I remember, that the problem did not exist with earlier kernels > > > (and this version of kubuntu) > > > > > > I think this might be a kernel bug introduced by some patch applied before > > > 2.6.12. > > > > It's not a bug; it's deliberate. :-) > > > > See this bug report: > > > > http://bugzilla.kernel.org/show_bug.cgi?id=4882 > > > > Thanks Alan for pointing to it. Seems like using sync on FAT devices > is a very bad idea... now the question is how to I make hald - or > whatever mounts the drive in the end - not to use the sync option... > but that is Offtopic I guess.
If you are using a recent version of Fedora, just update hald. They
realized what a serious mistake that was and fixed it in an update. I
had that option destroy a couple of USB flash memory cards just by
copying a 700 Meg file to them. It ended up beating on the FAT so bad
that even the wear leveling failed to protect it against flash wear-out.
Thanks to a suggestion one person made on the kernel mailing list I was
able to recover the burned out device (it only had a dozen or so bad
sectors - mostly the fat tables) by blind writing across the entire
drive using dd against the device and flawing out the burned sectors
(which then results in a good drive with a smaller internal spares
table, I guess).
> Thanks again!
>
> Cheers
> -Marc
Mike
--
Michael H. Warfield | (770) 985-6132 | [EMAIL PROTECTED]
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