which is the best root File system in embed linux system?

which is the best root File system in embed linux system?

[leo]

Hi,
MPC852T target board with 8MB flash, which kind foot file system is the
best selection among of:
1. Cramfs
2. EXT2
3. JFFS2
4. RAMDISK

Thanks advance!

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Re: which is the best root File system in embed linux system?

[Wolfgang Denk]

In message <200404211533.KAA04470@lists.linuxppc.org> you wrote:
>
> MPC852T target board with 8MB flash, which kind foot file system is the
> best selection among of:
...

You cannot optimize anything  without  spezifying  your  optimization
criteria  and  priorities.  What  is  important  for  you  - speed of
booting, memory footprint in RAM, memory footprint  in  flash,  being
able to write files to the filesystem, persistent sotrage of writtten
data, etc. etc.

What's best for my project is probably the worst for yours.

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
"Plan to throw one away.  You will anyway."
                              - Fred Brooks, "The Mythical Man Month"

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Re: which is the best root File system in embed linux system?

[jeffy]

>In message <20040422154403.6452042E2F@denx.de> you wrote:
>>
>> I have not measure the speed of accessing files, so have not the
>> exact concept:)
>
>Then go back one step: before using any software, start by writing down
>the requirements and specifications.
>
>> Now the EXT2 FS is about 13MB(whithout any applications), maybe it is
>> too biger?
>
>No, this is not the problem.
>
>> Oh, I am sorry that not write the detail! Now we have two kind of
>> 8XX boards, one is MPC855T board, and for low cost, we developed
>> MPC852T, one use 32M DOC, another use 8MB+512KB flash. I have success
>> building a EXT2 FS on DOC, and a JFFS2 FS on flash, but they all
>> seems unstable when turn off/on power frequently, so I am worry now,
>> and I want to know what bring on these unstable problems, our design
>> problems or DOC/FS inherent bugs?
>
>Assuming you use recent MTD and JFFS2 code, then JFFS2 should be
>absolutely stable on the 8MB flash system.
>
>As for ext2 on DOC: this is bounmd to fail, as ext2 was not designed
>to be used in a mode where sudden power-of without previous umount can
>occur.
>
>> Oh..., because turn off the power through hardware power switch, so
>> don't remount the file system!
>
>This is your problem. You cannot use ext2 for such a system, then.

Thanks a lot:)

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Re: which is the best root File system in embed linux system?

[Wolfgang Denk]

Dear David,

in message <1083483737.32758.146.camel@imladris.demon.co.uk> you wrote:
>
> > Yes, this is the logical consequence of your mis-use.
>
> For many classes of embedded system I don't consider unannounced power
> failure to be 'mis-use'. That's why we run powerfail tests on JFFS2 and

Neither do I. My "mis-use" only referred to the fact of using an ext2
filesystem in a system where powerfails are expected to happen.

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Life would be so much easier if we could  just  look  at  the  source
code.                                                   -- Dave Olson

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Re: which is the best root File system in embed linux system?

[David Woodhouse]

On Sun, 2004-05-02 at 11:20 +0200, Wolfgang Denk wrote:
> Neither do I. My "mis-use" only referred to the fact of using an ext2
> filesystem in a system where powerfails are expected to happen.

OK, that makes sense but I'd have called it 'misdesign' :)

--
dwmw2


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