[U-Boot-Users] redundant environment block

[Wolfgang Denk]

In message <OF1DF5789D.DD8FEF70-ON85256EBA.00649B07-85256EBA.00651617 at nanometrics.ca> you wrote:
> 
> As I understand it, the ENV_REDUND feature in u-boot protect the
> environment in flash from a power failure during saveenv.  It appears it
> will not protect it against accidental scribbling from errant
> code/processor.

Well, it does, as long as you overwrite only  one  of  the  redundand
sectors.  If  this  is your concern, then you should locate these two
sectors as  far  apart  form  each  other  as  possible,  ideally  in
different flash banks.

> I like to know from the community, whether it is important to protect it
> against flash scribbling,  or are the majority of flash environment
> corruption due to interruption to the saveenv command?

Actually I have never seen any corruption of the environment in flash
by either of these reasons in real life myself, nor with any  of  our
customers.  If  there  was a problem, it was usually an user's error,
which you cannot prevent.

But there are certain types  of  applications  where  reliability  is
critical,  and  then  such  a feature becomes important. But remember
that the protection is inteded for production use, and typical  usage
cases  there. If your software design allows "scribbling" on the boot
loader's flash memory, then you have a MAJOR problem anyway.


[Jut a note: I have  seen  quite  a  number  of  cases  of  corrupted
environment  when stored in EEPROM. I recommend NOT to use EEPROM for
the environment to all our customers. (Also it's slow  as  hell  when
booting.)]

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
Brain: an apparatus with which we think we think.    - Ambrose Bierce