FC4 CF-based Router

Bob Chiodini rchiodin at bellsouth.net
Thu Dec 15 14:54:08 UTC 2005

On Thu, 2005-12-15 at 05:53 -0800, Steven Ringwald wrote:
> Bob Chiodini wrote:
> >Do you have a CF interface in your development/desktop?  If so, then why
> >not just copy your small installation directly to an ext2 or ext3
> >partition on the CF and grub-install grub as the boot loader?  
> >
> >If you don't have a CF interface on your desktop, then either get one,
> >or if your target can boot a CD...  Boot up Knoppix, format the CF, copy
> >your small installation to the CF over the network (SCP, NFS) then grub-
> >install grub to the CF.
> >
> >You will most likely want to mount your root file system read-only and
> >place all of your volatile data in a tmpfs file system to avoid
> >shortening the life of the CF.  
> >
> >You can also put your entire file system in a ramdisk (initrd) and run
> >the system out of RAM.  You will probably need a lot of RAM, but you
> >don't have to worry about FSCK'ing the CF and it's probably faster
> >without the CF I/O.
> >
> >CF to IDE adapters:
> >
> >http://mach5products.com/merchant2/merchant.mvc?Screen=CTGY&Category_Code=CF
> >
> >We use one similar to the $19.95 version near the bottom of the page.
> >
> Bob,
> Thanks for your response! Yes, I have a CF <-> IDE adapter in my box. 
> The problem that I am having with ext2/ext3/etc is that no matter what I 
> specify, the system comes up (rw) (based on what /proc/mounts and touch 
> /foo show). I have the 'ro' flag on my kernel line in the grub.conf, and 
> have the noatime,ro line in my fstab, but they still seem to want to 
> come up rw... I have even gone so far as to wipe out /etc/mtab and 
> /etc/blkid.tab*, but haven't had much luck getting it to stay read-only 
> past the initrd stage.... I have gotten it to stay read-only by creating 
> a read-only filesystem image (like iso9660 or cramfs), but haven't had 
> much luck getting it to boot from another partition. (I basically have 
> to dd the iso image to /dev/hda3 and mount that in the initrc's init 
> script).
> Steve


A couple of questions:  Is your mount command coming from busybox?  Can
you mount -o remount,ro the file system?  noatime,ro in fstab is how it
was done on one of the embedded systems I was working on, but it was not
CF based. 	


aph what is 

Presuming busybox:  Are you mounting the file system with the --ro
option in your linuxrc file?  This is the linuxrc file I used, but I
cannot verify that it worked correctly, WRT mounting the root file
system ro, I thought so:


echo Mounting /proc filesystem
mount -t proc /proc /proc
echo Creating root device
mkrootdev /dev/root
echo 0x0100 > /proc/sys/kernel/real-root-dev
echo Mounting root filesystem
mount --ro -t ext3 /dev/root /sysroot
umount /proc
pivot_root /sysroot /sysroot/initrd

This was a 2.4 kernel, based system.  It started out from RH7.  Nash was
probably the only piece that was kept.


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