Root FS on Flash?

[Dan Malek]

Wang Yong wrote:


> .... i have a question: how to make root file system on the
> flash memory? by now, most embedded linux employ NFS as root file
> system.

The diskless NFS root file system is simply used for convenience and
to reduce application development time.  You can put a root file
system on anything that will hold the bits.


>         does anyone has any experience on it? is there a embedded linux
> has done it? any comment and suggestion are welcome. thank you.

Yes, there are many systems using a variety of solutions to Flash rom
root file systems.  You have to consider your own application
requirements to choose what is appropriate for you.  You can use
a compressed initrd stored in flash rom, which is uncompressed into
a ram disk.  Another popular alternative is PCMCIA flash disks,
compact flash or Smart Media cards.  You can put a file system on them,
partition them, and compress some or all of the data.  Least favorite
on my list, but used by some people, is soldered on-board flash rom
parts.  Wear leveling and dynamic allocation are complex algorithms,
and above a rather small size compact flash cards are more cost effective.

All of this is supported by standard Linux distributions, and the boot
code in the PPC port handles it well.


	-- Dan

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