[Yaffs] some questions

Hi all,
I have a few questions about yaffs2. Thanks in advance for replying.

1. Yaffs2 now ensures that pages within a block will be written sequentially.
With multiple threads is it possible that pages within a block may be
written out of order?
2. Ext4 is supposed to better in multithreaded performance in
comparison to yaffs2 in Android.
   What sorts of problems have to solved in yaffs2 for better
multi-threaded performance?.
   How can one contribute toward this effort?
3. Is it possible to get reasonably accurate runtime memory
consumption from checkpoint size,
     What is the approximate relationship between checkpoint size and
runtime mem consumption
     is there a linear relationship like,
    Checkpointsize + ShortOpCacheSize + YAffs tempbuffers + (?) = Runtime
memory consumption
4. I want to take yaffs2 benchmark measurements on an aged
filesystem(ie which has been used for quite some months).
   Any ideas for how to artificially create such an yaffs2 image?.
   I want something like, if i create 100MB aged yaffs2 image , is
there a way  i can write it like multiple times to create a larger,
say 1GB image?

Thanks ,
mugunthan