UBI bad block Management

[Brijesh Singh]

Hi,
  I am satisfied by your last reply Artem.Seems Logical."It is MTD's
and only MTD's business to manage bad blocks."
  I had suggested three ways that would help UBI to maintain a Bitmap
of Bad Blocks.This would help speed up Initialization process.So if we
don't have on-flash BBT,maintaining a Bitmap will be an advantage.


On 2/14/07, Artem Bityutskiy <dedekind at infradead.org> wrote:
> Hi,
>
> On Wed, 2007-02-14 at 14:58 +0530, Brijesh Singh wrote:
> > Hi,
> >    The flash devices are getting of bigger in Size.The Init Scan time
> > will increase with bigger Size flash.How long are we going to rely on
> > MTD for Bad block Management.Even MTD doesn't maintain List but calls
> > the hardware, if hardware supports it.
> > This can be done in two ways,
> > 1:) Straight right the bitmap,and if changed erase it.We can do it in
> > One reserved block.
> >            If allowed bad blocks are 20%,it will be erased 20% times
> > of total PEB count.
> > 2:)Keep a Queue in Scan of Bad blocks.Ec header contains one field
> > called last bad block.Which is PEb no.So if block is found bad,next
> > block to be written first will have Bad block no in EC.So it is
> > maintained across reboots.
> > 3:)Keep a Log in reserved Block.When it is getting full,create bitmap
> > and write it on the block.This will reduce the erasing of that block.
> >
> > So we can maintain Bad block Map in UBI if it is necessary.
>
> I really tried to realize what you mean, but failed, sorry. I do not
> understand at all what are you about. May you re-phrase?
>
> --
> Best regards,
> Artem Bityutskiy (Битюцкий Артём)
>
>