[U-Boot] understanding mkimage a bit more

[Charles Krinke]

On Fri, May 6, 2011 at 11:33 AM, Eric Cooper <ecc at cmu.edu> wrote:
> On Fri, May 06, 2011 at 11:13:39AM -0700, Charles Krinke wrote:
>> The next issue is the flash file system. Normally, I like to use JFFS2
>> for reliability as embedded devices frequently have their power switch
>> turned off at any time. I do understand that UBIFS is getting more
>> prevalent lately and I wonder if you or anyone else has a comment on
>> the suitability of UBIFS in an environment where the power will be
>> turned off and on exexpectdly and frequently.
>>
>> In googling UBIFS problems, I do see posts across the internet of
>> UBIFS devices that will not boot after power is turned off and on. My
>> experience with JFFS2 is that it has always recovered during boot with
>> all the designs I have participated in over the last several years.
>> Admiteddly, the act of doing something like "scandisk" on boot slows
>> the boot down, but does seem to add reliability.
>
> It has been very resilient to power failures in my experience -- the
> Linux ubifs code has always managed to recover, and very quickly.
>
> The main pitfall is that U-Boot's support for ubifs is only the
> read-only subset of Linux's.  That means it can read from a consistent
> ubifs partition, but not from one that needs repair (because that
> requires writing).  So you can't rely on booting your Linux kernel
> *from a ubifs partition*.  But if you have your kernel in a separate,
> read-only uImage partition you should be fine (it's just more annoying
> to update kernels).
>
> --
> Eric Cooper             e c c @ c m u . e d u
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Dear Eric:

I appreciate your kind reply. I wonder if you (or someone else)  might
consider doing me another favor.

I understand a bit about setting up JFFS2 and have used
drivers/mtd/maps for this purpose. I also understand that in setting
up UBIFS, I will enable UBIFS in the linux kernel.

But, on the flash, I am a little perplexed as I have not done this before.

Can someone give me a few hints and clues about setting up the flash
in the manner Eric describes, please?

-- 
Charles Krinke