[U-Boot-Users] jffs2

[Robert Schwebel]

On Thu, Mar 06, 2003 at 10:21:45AM +0100, Wolfgang Denk wrote:
> I don't do it this way. Usually I split  filesystem  and  kernel,  as
> this gives both more flexibility and easier to handle image sizes.

Hmm, but you have to agree with yourself on a maximum kernel partition
size first. How do you handle this? Are you sure that even if 2.6 is out
there will be enough space? 

> It is IMHO a bad idea to have the root  filesystem  writable  in  the
> first  place.  Usually  it  means that you don't understand (probably
> never bothered about it) what's going on in your filesystem. You  may
> end  up  easily  with  a  system that fails in the field after just a
> couple of weeks / months because  of  unintended  and  unknown  write
> operations.

You may have guessed it - the rootfs is indeed mounted r/o on our
system, due to the reason you mentioned. But I in general would like to
be able to mount it r/w in case of maintainance or during development.
So jffs2 would surely comes close to what I would like to see. 

> I always propose a design with a  read-only  root  filesystem,  which
> contains   all   the  "constant"  data  like  libraries,  tools,  and
> applications, and only a small writable  flash  filesystem  (if  any,
> often it makes no sense at all) for things like configuration data.

That's how it is designed. 

> But here it goes: if you do it this way - what do you need JFFS2 for?
> For logfiles? Bad choice. For config data? You can probably  use  the
> U-Boot  envrionment  sectors  as  well - now that we have implemented
> redundancy this is a pretty safe method  for  anything  that  can  be
> represented as (short) string.

Well, just to shock you: we have a SQL database which holds our config
data :-) But it has it's own jffs2 data partition. 

> > And what is DPLG? 
> 
> You do read this list, don't you?

Yes, but I don't print out the archive each and every day and put it
under my pillow ;-) 

Robert 
-- 
 Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de
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