Root FS on Flash?

Root FS on Flash?

[Wang Yong]

hi,
	we're now working on porting linux to IBM PPC401D2, a embedded
controller. here, 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.
this solution is not suitable for us. so we decide to make a root fs,
such
as minix, on flash memory.
	does anyone has any experience on it? is there a embedded linux
has done it? any comment and suggestion are welcome. thank you.

regards,
Wang


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Re: 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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