A fresh document on this subject is now available at: 
http://www.aleph1.co.uk/gitweb?p=yaffs-docs;a=summary
It was posted on 28 March 2014  -  click on  "snapshot" to download it.
It discusses:-
Differences in users' perceptions of "A Computer" and "An embedded system"
Cosequences of power failures in embedded systems in service.  
Importance of reliability.
Pros and Cons of Flash chip types and of Caching data in FS
Testing regimes used on Yaffs

We shall soon be posting it on www.yaffs.net too.
Thanks,
LvS
-- 
Laurie van Someren, Aleph One Ltd, The Old Courthouse, Bottisham 
CAMBRIDGE CB25 9BA UK www.aleph1.co.uk and 
www.yaffs.nethttp://www.aleph1.co.uk/gitweb?p=yaffs-docs;a=summary