Why can't i mount a ramdisk in ep2c35 DEV board

[Altera_Forum]

I have run the Linux .But I want to use the ramdisk. i find i can't mount  

 # dd if=/ramfs.img of=/dev/ram0 dd if=/ramfs.img of=/dev/ram0 6+1 records in 6+1 records out# mount /dev/ram0 /mnt/ide0 mount /dev/ram0 /mnt/ide0 can't create lock file /etc/mtab~31: Read-only file system (use -n flag to overr ide)  when i type the next command # dd if=/dev/zero of=/dev/ram0 bs=1k count=4096 dd if=/dev/zero of=/dev/ram0 bs=1k count=4096 /dev/ram0: No space left on device 4097+0 records in 4096+0 records out  # mke2fs -s0 -vm0 /dev/ram0 4096 mke2fs -s0 -vm0 /dev/ram0 4096 mke2fs 1.25 (20-Sep-2001) /dev/ram0 is mounted; will not make a filesystem    help me !!

[Altera_Forum]

You should use Initramfs instead of romfs. There is no need to mount ramdisk. Follow, 

http://forum.niosforum.com/forum/index.php?showtopic=3174 (http://forum.niosforum.com/forum/index.php?showtopic=3174)