[fedora-arm] uImage-2.6.30-sheevaplug is definitely broken

[Gordan Bobic]

On 01/08/2011 07:33 PM, Chris Tyler wrote:
> On Sat, 2011-01-08 at 19:05 +0000, Gordan Bobic wrote:
>> It also sounds ill advised to be burning things that are supposed to get
>> updated relatively frequently (kernels DO get updated) to
>> non-replaceable flash. Keeping the kernel with the rest of the distro on
>> the easily removable/replaceable flash media is probably a more
>> reasonable long-term solution. Using built in flash is fine for embedded
>> appliances that only see 1-2 updates/year, but not necessarily for
>> bleeding edge desktop distributions like Fedora.
>
> Well, there's a huge difference between putting / on NAND and the kernel
> on NAND. Assuming just a 10,000-write-cycle durability, updating the
> kernel every 3-4 days (100x/year) gives you 100 years of life.

Assuming you actually get your 10,000 erase cycles out of it - and that 
is a big assumotion. I have seen a lot of consumer grade MLC flash fail 
after a few dozen erases (USB sticks, CF cards). In general, if it 
survives the first 20 or so I find it does last fine, but assuming that 
you will get 10,000 erase cycles out of it seems like an unnecessary 
risk when you will actually end up bricking the device permanently. An 
SD card, OTOH, is easy to replace.

Advantages of keeping it on the same media as the rest of the distro 
include but are not limited to:

1) It makes the kernel image easily available and accessible without any 
additional magic.

2) It is what anybody who has used Fedora on a different distro will 
intuitively expect.

3) It makes sense to keep the kernel in the same place as /lib/modules, 
as the chances are that you won't get very far if they don't match, 
especially on a distro like Fedora where just about everything is a module.

What are the percieved advantages of having the kernel image on built in 
nand? The only advantage is for devices that for some reason aren't 
supported by u-boot or another similar boot loader. AC100 is one such 
device, but u-boot support is being worked on.

Gordan