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Re: Some (possibly stupid) questions about creating a JFFS2 filesystem




justin.wojdacki@xxxxxxx.com said:
>  1. How do I keep JFFS's garbage collection thread from touching a
> particular block in flash? For the system in question, the bootloader
> is on the same device as the JFFS partition, and I (obviously) don't
> want JFFS's garbage collection erasing this block.

You use separate partitions for the bootloader and the JFFS2 image. JFFS2 
will use the whole of the MTD 'device' it's told to mount on, but that 
doesn't have to be the whole chip. Look at the partitioning stuff in all 
the map drivers.

> 2. Why does the filesystem get so big? I have an input filesystem
> that's ~2.7M and the resulting jffs2 image is 6M.  

Normally this happens when people specify an eraseblock size of 64 bytes 
when they meant to say 64KiB -- or indeed because you _can't_ tell it 
'64KiB'; you have to tell it '65536' instead. 

Actually, the latest versions of mkfs.jffs2 will assume you meant KiB if you 
give a number less than 4096.

--
dwmw2



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