Okay, after a chat with Kris at TS, I know that the sync command will cause the
file system buffers to be written to the SD card. Okay, fine but I still find
that if you don't unmount the read/write JFS partition, you have to fsck the
/dev entry before the system will let you mount it after a restart. That
defeats the purpose, IMHO. Seems to me that any use of fsck is evil because
you don't know how long it will take to complete and if you have a faceless
embedded system, the layperson will think it's broken.
So my next experiment is to try an EXT3 partition. That has one benefit in
that it can be much smaller than the minimum JFS partition which is 16MB. Of
course I had to rebuild the kernel with EXT3 support. I seem to be able to
skip the sync operation (unless that was a bug in earlier JFS implementations
as I went from 2.6.21 to 2.6.34). I do see mount warnings telling me to run
fsck.
So, does anyone have more real-world experience here? Technically, I'm only
writing to a very small preferences/settings file and never leave the file open
for more than it takes to write out a few dozen words and then the file is
immediately closed. The chance that the file is open when power is turned off
is really small.
--- In "Blair" <> wrote:
>
> Given a 7350 booting to the Busybox shell prompt (not full Debian).
> The file system is mounted read-only and by design you have to run the save
> script to write any changes to the SD card. I'd like to be able to store a
> user-preferences file generated and modified by a C program somewhere on the
> SD card but I don't want to have to run the save script.
>
> So, I tried making a new JFS partition (in place of the eclipse partition).
> But there are two problems. First, if I make a change to something on that
> partition (new file, edit a file, etc), and I turn off the power, the system
> forces me to run fsck before it will let me mount the partition. Second, the
> changes have been lost.
>
> What is the proper way to accomplish this? I though JFS was a power-loss
> tolerant file system.
>
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