max_ec value is shown as 1

max_ec value is shown as 1

[Sandeep Kumar]

Hi all,
I was recently trying to create a volume on a UBI device and i could
not understand the following.

[root@localhost ubi]# cat /proc/mtd

dev:    size   erasesize  name
mtd0: 02000000 00020000 "mtdram test device"
mtd1: 04000000 00004000 "NAND simulator partition"

[root@localhost 0]# modprobe ubi mtd=0
[root@localhost ubi]# ls /sys/class/ubi
ubi0  version

[root@localhost ubi]#ubimkvol 0 1024 2MB dynamic vol0 ubi0


[root@localhost ubi]#cd /sys/class/ubi/ubi0/
[root@localhost ubi0]# cat max_ec
1

Well, Can anyone help me in determining that why the max_ec is shown as 1.

-- 
Regards,
Sandeep





 	
If the facts don't fit the theory, change the facts.

Re: max_ec value is shown as 1

[Artem Bityutskiy]

Hello Sandeep,

On Thu, 2007-01-11 at 10:44 +0000, Sandeep Kumar wrote:
> [root@localhost ubi]#cd /sys/class/ubi/ubi0/
> [root@localhost ubi0]# cat max_ec
> 1
> 
> Well, Can anyone help me in determining that why the max_ec is shown as 1.

What did you expect instead?

You fed empty flash to UBI, UBI erased each eraseblock once and put
erase counter header to each eraseblock, with erase counter = 1, because
there was one erase.

And max_ec which means maximum erase counter value is 1.

-- 
Best regards,
Artem Bityutskiy (Битюцкий Артём)

Re: max_ec value is shown as 1

[Sandeep Kumar]

On 1/11/07, Artem Bityutskiy <dedekind@infradead.org> wrote:
> Hello Sandeep,
>
> On Thu, 2007-01-11 at 10:44 +0000, Sandeep Kumar wrote:
> > [root@localhost ubi]#cd /sys/class/ubi/ubi0/
> > [root@localhost ubi0]# cat max_ec
> > 1
> >
> > Well, Can anyone help me in determining that why the max_ec is shown as 1.
>
> What did you expect instead?
>
I got it, I think. I mistook this value as the maximum erase count for
a leb on that device. And thats why I was surprised.

I think information is used for wear leveling.

> You fed empty flash to UBI, UBI erased each eraseblock once and put
> erase counter header to each eraseblock, with erase counter = 1, because
> there was one erase.
>



> And max_ec which means maximum erase counter value is 1.
>
> --
> Best regards,
> Artem Bityutskiy (Битюцкий Артём)
>
>


-- 
Regards,
Sandeep





 	
If the facts don't fit the theory, change the facts.

Re: max_ec value is shown as 1

[Artem Bityutskiy]

On Thu, 2007-01-11 at 16:52 +0530, Sandeep Kumar wrote:
> I got it, I think. I mistook this value as the maximum erase count for
> a leb on that device. And thats why I was surprised.

Maximum LEB EC is 0x7FFFFFFF (31 bit) in current implementation.

-- 
Best regards,
Artem Bityutskiy (Битюцкий Артём)