On Saturday 19 March 2011 07:48:05 srimugunthan dhandapani wrote:
> Hi all ,
> This is my first mail to the yaffs group. I am learning yaffs file
> system and i have some doubts trying to understand checkpointing and
> how yaffs copes without having a on-disk format.
>
> 1. On mounting how is the starting of the checkpoint block located. I
> guess it should be at a fixed location on flash as we cant scan for
> the checkpoint start block. Then if we use the same block for
> checkpoint wont it hurt the wear of that particular block?

It is not at a fixed location but has to be found by scanning.

> 2. Is the checkpoint information stored contiguously  on the flash or
> is it scattered ?

It might be scattered.

> 3. Where is the super block stored on the flash?

There is no superblock.

> 4. When we open an existing file how do we get the tnode information?
> When checkpointing does the tnode structure of all files also
> checkpointed?

Yes the checkpoint info stores the info in tnodes.

> 5. Roughly how much RAM will be needed for a 512 GB flash assuming it
> stores 1000 files with size of 500MB each.

I have not tested yaffs with that much flash and there might be some issues,

It would need a lot of RAM - many hundreds of Mbytes.

-- CHarles