Unable to write to some JFS partitions

[Jeremy Bowen]

> 1. Don't use JFFS, use JFFS2.

OK. But I think there is an underlying problem with what I've currently got
that I'd quite like to understand. Why does one JFFS partition work fine
while the 2 others I try, don't ?

> 2. Don't attempt to use partitions which have fewer free 
> blocks than are required to make progress --

How many free blocks are required to make progress ?

> combine all 
> your file system space into one JFFS2 partition. 

Is this the "mtdconcat" functionality ?

Actually I'm developing on a board with 8Mb Flash but the production units
will only have 4Mb so the partitions I've defined are somewhat artificial.

Do I need 2 free flash sectors in order to us JFFS ?

> Note that there exist bootloaders which can boot
> from JFFS2 so you can put the kernel in there too.

I'm using Das U-Boot.

> 3. eraseall works on the /dev/mtd character devices, not the block 
>    devices.

bash-2.05# eraseall /dev/mtdblock/7
eraseall: /dev/mtdblock/7: unable to get MTD device info
bash-2.05# eraseall /dev/mtd/7
eraseall: /dev/mtd/7: unable to get MTD device info

Eraseall doesn't seem to work for me whatsoever.


Jeremy