Saquib wrote:
> (1) *YAFFS2 Direct Interface* : What is the use of this interface? Is it
> mandatory when I use YAFFS2?

YAFFS was originally developed as a filesystem module to be loaded into the
Linux kernel and accessed indirectly via the standard filesystem calls. It
has since been ported to other platforms including WinCE and eCos. The
Direct interface is for use in a system when you have no filesystem
interface, or do not want to use your platform's filesystem layer, which
would likely only be relevant in very specialised environments.

> (2) *Garbage Collection and Wear-Levelling*: How do I test these things
> are working?

Set the yaffs_traceMask appropriately, run a stress test, collect the
diagnostic output and analyse it to determine whether these features are
operating correctly. The tracemask is a bitfield; its bits are named
YAFFS_TRACE_* and are defined in yportenv.h.

See also http://www.yaffs.net/yaffs-debugging

> (3) *4K Page Size* : This chip supports 4K page size. Is there any
> changes required in YAFFS2 source code for 4K support.

I don't think so, provided the mtd (NAND chip) driver for your chip sets up
the yaffs_DeviceStruct appropriately.

> (4) *Multiplane Programming* : The newer chip we are planning to use is
> multiplane NAND chip. How does YAFFS2 support Multiplane chip?

YAFFS2 is known to support MLC parts. Others are better placed to comment
here, but I think it's largely transparent and would depend on having a good
mtd driver which uses the right ECC algorithm. You may need to look
carefully at the chip spec sheet to see whether a more complicated ECC
algorithm is required for the ECC YAFFS calculates internally on the tags it
 stores in the spare area of each page.


Ross

-- 
Embedded Software Engineer, eCosCentric Limited.
Barnwell House, Barnwell Drive, Cambridge CB5 8UU, UK.
Registered in England no. 4422071.                  www.ecoscentric.com