> Hi
>     I want to know clearly the maximam file system size for YAFFS2 can
> handle.
>     In file ysffs_guts.h, there're ysffs_Tags structure:
>    typedef struct {
>     unsigned chunkId:20;
>     unsigned serialNumber:2;
>     unsigned byteCount:10;
>     unsigned objectId:18;
>     unsigned ecc:12;
>     unsigned unusedStuff:2;
>
> } yaffs_Tags;
>      I can calculate the maximum file system size YAFFS2 can handle by
> following algorithm:
>     (2^20)*(2^18)*(2kb)= 2^49B     //Chunk size is 2kb
>     Am I right?
>     Appreciate for your reply!  Thanks.

While you have chosen the wrong structure here (yaffs_Tags is only relevent to 
the yaffs1 mode of operation), the basic idea is almost correct.

yaffs2 uses the yaffs_PackedTags2 structure. This allows up to 32 bits for the 
chunk Id. That limits any particular file to 2^42 (assuming 2048-byte 
chunks).

However, calculations limit any one partition to 2^31 chunks in total. ie a 
total partition of 2^41.

However, all the structures use RAM and thus real-world RAM limitations are 
more likely to cause problems first.

-- Charles