Re: Viable PPC platform?

[Eugene Surovegin <ebs@ebshome.net>]

On Wed, May 10, 2006 at 12:11:41PM +0100, Alex Zeffertt wrote:
> On Tue, 9 May 2006 10:15:20 -0700
> Eugene Surovegin <ebs@ebshome.net> wrote:
> 
> > On Tue, May 09, 2006 at 05:41:01PM +0100, Alex Zeffertt wrote:
> > > On Tue, 09 May 2006 10:38:19 -0400
> > > geneSmith <gd.smth@gmail.com> wrote:
> > > 
> > > > I have a ppc405gpr system with 64M ram and 4Meg flash in a
> > > > AM29LV320. Is this a viable platform for linux? Can a filesystem
> > > > (JFFS2?) be put this flash type?
> > > > 
> > > 
> > > I would create an initrd and put every file that doesn't need
> > > to be changed persistently into it instead of JFFS2.
> > 
> > After many years of doing embedded Linux stuff I still don't 
> > understand why people are so fond of initrd.
> > 
> > For temporary stuff - tempfs is much better and flexible. For r/o 
> > stuff - just make separate MTD partition (cramfs, squashfs) and
> > mount it directly as root. Both options will waste significantly
> > less memory.
> > 
> 
> Okay, let me qualify my answer.  It depends on whether you need to
> make persistent changes to the filesystem in flash.  If so, and given
> that your flash is only 4MB, I would recommend moving files to
> somewhere else, e.g. an initrd, because if when a JFFS2 FS is
> approaching full, you often find that writes to flash hang
> while JFFS2 searches for blocks to use as a scratchpad.  This has been
> my experience anyway.
> 
> If you don't need to make persistent changes to files, then I'm sure
> cramfs in flash as a rootfs would work well, with a tmpfs partition
> mounted on /tmp and /var.

You missed my point. initrd should be stored somewhere - in the same 
flash . In this case there is no reason to actually use initrd instead 
of just direct mount from flash.

-- 
Eugene