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

[Neng-Yu Tu (Tony Tu)]

Dear Andy:

> >
> > device nand0 <neo1973-nand>, # parts = 6
> > #: name                        size            offset
mask_flags
> > 0: u-boot              0x00040000      0x00000000      0
> > 1: u-boot_env          0x00040000      0x00040000      0
> > 2: kernel              0x00800000      0x00080000      0
> > 3: splash              0x000a0000      0x00880000      0
> > 4: factory             0x00040000      0x00920000      0
> > 5: rootfs              0x076a0000      0x00960000      0


> One of the choices that we may do is to cut rootfs into two, because the
> amount of time spent mounting is proportional only to the partition
> size.  We can create a 50MB "early boot" partition we can mount to get
> started with the initscripts, and mount the remaining 200MB in the
> background at a different mountpoint.  This will reduce the effective
> initial JFFS2 mount time to 20% of what it is now.

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
;)

> 
> Werner is looking at trying to find a different way to optimize the
> mount time, we said that early next week we will finalize the decision
> on the partition set we will use, but I would propose we cut the rootfs
> in two as described if Werner didn't have luck in speeding it up by a
> considerable amount.  Of course even if he speeds it up by 5% that is
> really good either way.
> 

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 ;)

> 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.

Tony Tu


> - -Andy
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