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AW: contributing a failsafe update meachanism for FIS from within ecos applications
- From: "Neundorf, Alexander" <Alexander dot Neundorf at jenoptik dot com>
- To: "Andrew Lunn" <andrew at lunn dot ch>
- Cc: <ecos-devel at sources dot redhat dot com>
- Date: Mon, 18 Oct 2004 17:21:24 +0200
- Subject: AW: contributing a failsafe update meachanism for FIS from within ecos applications
> -----Ursprüngliche Nachricht-----
> Von: Andrew Lunn [mailto:email@example.com]
> Gesendet: Montag, 18. Oktober 2004 16:50
> An: Neundorf, Alexander
> Cc: firstname.lastname@example.org
> Betreff: Re: contributing a failsafe update meachanism for FIS from
> within ecos applications
> > > You should have CDL to control where the second flash
> block is. Its
> > > bad to assume its the next block.
> > Really ?
> > IMO it would be ok if the blocks are directly one after the
> other. One could think of it as a fis dir twice as big as
> before containing two copies of this fis dir.
> But what about people who want to add this to an existing project and
> there only free blocks in flash are somewhere else.
> I would think about trying to use the existing format so that it
> remains backward compatible. I think about add a dummy image to the
> fis list. Dummy in that it start and length are 0. But the name would
> be something like. "Fis Valid*" The sting is 16 charactors long. So
> there are 5 unused charactors after the \0. You could put your magic
> numbers there. This will probably be backward compatible with old
> redboots. They will just see it as a normal entry with some junk after
> the end of the string. Where i showed "*" in the sting, if you think
> carefully about ASCII and the binary representation, you might be able
> to come up with a set of charactors which differ by resetting 1's to
> give some sort of meaningful mapping to the state of the FIS
Ok, I'll post a modified patch which uses "$Magic" as "magic number" in the next days, with "$Magic0" for the fis table 0 and "$Magic1" for fis table 1. This leaves 8 bytes room for the valid_flag and the version_count.