Fwd: Hello -- NAND/NOR Flash design for GTA02

[Andy Green]

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Somebody in the thread at some point said:

Hi Tony -

> I think we should consider early boot into smaller than 32 MB as target, not
> only for GTA02 release, but also we do not need 32 MB data/apps during boot
> ;)

Currently we use 45MB of the rootfs.  Also with JFFS2 it writes it and
later compresses it AIUI, you need some free space or things go very
slowly or not at all when you try to fill it.  So we will need some
headroom over what the actual compressed final footprint is.

> Well, I thing Werner really got something during hxd8 war :) Maybe he will
> also consider mount different type of file system then.
> 
> 5% is too easy for Werner, I would say save 80% current time is ideal
> challenge for Werner ;)

Excellent then :-)  Mickey would like to see yaffs in there instead
which doesn't have the slow behaviour -- but it doesn't have compression
either (there's probably a way around that).

http://www.yaffs.net/comparison-between-yaffs-yaffs2-and-jffs2

Either way we need to do whatever we are doing in the next week, and if
we don't do anything else for some reason, we will need to be doing the
JFFS2/split method.  I'll be super happy not to have to do it because
Werner gave a magic solution.

>> If we go that way, we need to consider the impact on packaging paths.
>> Probably we should leave all the packages to point where they are, and
>> have /usr and so on in the "early boot" partition.  Then other packages
>> should place stuff in something like /opt or /usr/local which is mounted
>> or mounted --bind to the second, larger partition.
>>
> 
> I think this way might affect _installer_ design, if want to install program
> want to start during boot, this might be potential constraint for app
> developer.

It's just a packaging issue.  If the package wants to deliver an
initscript that depends on the larger partition being mounted, it will
be able to block in the background until the partition is mounted.

Apparently we move to upstart for initscripts which allows expression of
initscript dependency and parallel execution, it has a
"block-device-added" event that fits this situation.

http://www.linux.com/articles/57213

- -Andy
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