Specifications
read-only ramdisk:
#!/bin/sh
...
# Won't work on read-only root: mkdir /tmpfs
mount -t tmpfs tmpfs /tmpfs
mkdir /tmpfs/tmp /tmpfs/var
# Won't work on read-only root: ln -sf /tmpfs/tmp /tmpfs/var /
...
The commented out sections will of course fail on a read-only root filesystem, so you have to create the
/tmpfs mount-point and the symbolic links in your root filesystem beforehand in order to successfully use
this setup.
9.3. Using MultiMediaCards in Linux"
The MultiMediaCard (MMC) is a flash memory card standard.
Booting Linux with a MMC card connected to the m28 you should find in the bootlog something like that:
mmc0: new high speed SD card at address 0002
mmcblk0: mmc0:0002 00000 1.90 GiB
mmcblk0: p1
If the mmc card is detected, you should see at least the following device files:
/dev/mmcblk0
If there are partitions on it, you see the following device files:
/dev/mmcblk0pX
X =[1..n] with n=number of partitions
mount the partition:
root@generic-armv5te:~# cd /tmp/duts
root@generic-armv5te:/tmp/duts# ls -al mmc
total 0
drwxr-xr-x 2 root root 40 Oct 2 16:59 .
drwxr-xr-x 3 root root 60 Oct 2 16:59 ..
root@generic-armv5te:/tmp/duts# mount
rootfs on / type rootfs (rw)
192.168.1.1:/opt/eldk-5.2.1/armv5te/rootfs-lsb-sdk/ on / type nfs (rw,relatime,vers=3,rsize=4096,wsize=4096,namlen=255,hard,nolock,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=192.168.1.1,mountvers=3,mountproto=tcp,local_lock=all,addr=192.168.1.1)
proc on /proc type proc (rw,relatime)
sysfs on /sys type sysfs (rw,relatime)
none on /dev type tmpfs (rw,relatime,mode=755)
/dev/mmcblk0p2 on /media/mmcblk0p2 type vfat (rw,sync,relatime,fmask=0022,dmask=0022,codepage=cp437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
/dev/mmcblk0p3 on /media/mmcblk0p3 type ext4 (rw,sync,relatime,data=ordered)
devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /var/volatile type tmpfs (rw,relatime)
tmpfs on /media/ram type tmpfs (rw,relatime)
root@generic-armv5te:/tmp/duts# df
Filesystem 1K-blocks Used Available Use% Mounted on
rootfs 330279532 155153328 158348988 50% /
192.168.1.1:/opt/eldk-5.2.1/armv5te/rootfs-lsb-sdk/ 330279532 155153328 158348988 50% /
none 127104 140 126964 1% /dev
/dev/mmcblk0p2 30642 12666 17976 42% /media/mmcblk0p2
/dev/mmcblk0p3 1781936 1187500 503916 71% /media/mmcblk0p3
tmpfs 127104 168 126936 1% /var/volatile
tmpfs 127104 0 127104 0% /media/ram
9.3. Using MultiMediaCards in Linux" 108