Re: ramdisk/tmpfs/ramfs/memfs ?

[David Woodhouse]

[e-mail] said:
> btw I get my initial root filesystem from a compact flash that can be
> accessed just like a hardisk. It's writeable also like a harddisk, but
> we boot with it readonly, and only mount it rw if we want to save
> config or whatever. We definitely wouldn't swap to it as it has
> limited erase/write cycles. The filesystem is compressed ext2.

Why copy it into RAM? Why not use cramfs and either turn the writable
directories into symlinks into a ramfs which you create at boot time, or 
union-mount a ramfs over the top of it?

[e-mail] said:
> As for using JFFS2 + MTD ramdisk intead of ext2+e2compr+ramdisk is not
> an option as the only advantage would be journalling, you still can't
> resize. IMHO JFFS is only required where you have flash without an IDE
> interface.

True. We are currently lacking a compact, compressing, journalling 
filesystem for use on block devices. It's been suggested that we could make 
JFFS2 work on them, by making a fake MTD device which uses a block device 
as backing store. Nobody's yet shown me the code though :)

--
dwmw2