Re: [Gumstix-users] Flash FileSystem

[Craig H. <cr...@gu...>]

On Sep 20, 2005, at 2:11 PM, Steve Folta wrote:

> "Craig Hughes" <cr...@gu...> wrote:
>
>> [JFFS2] will allocate a new PAGESIZE chunk though anytime you  
>> overwrite
>> something, and that means 4kB each time, until it garbage collects
>> all the dirty chunks.
>>
>
> That is not my understanding at all.  What's your reference for that?

My understanding from http://sources.redhat.com/jffs2/jffs2-html/ 
node3.html and observing stuff like the output of df.

I believe that when you try to write to a file, JFFS2 will mark the  
previously-used node for that chunk of data as "invalid", and  
allocate a new node (of size PAGESIZE) to write the data to.   
Eventually, the garbage collector will come through and clean up the  
invalid node(s).  Also, I believe the garbage collector will take  
care of moving not-often-written blocks around in flash so as to deal  
with wear-levelling across the entire device.

> Do the Gumstixen use NOR or NAND flash?

NOR

C