[Q] where is ramdisk.img ?

hi, all!
Modify /init.rc configure file is my plan, in android(linux) box, /(rootfs) locate RAM.
So, modify ramdisk.img(initrd.img) is aim, However, I find any image file except recovery backup image:

root@android:/ # /system/xbin/busybox find / -name '*.img'
/mnt/sdcard2/clockworkmod/backup/2012-01-01.00.03.03/boot.img
/mnt/sdcard2/clockworkmod/backup/2012-01-01.00.03.03/recovery.img
/system/etc/firmware/modem.img


Did the partition that ramdisk.img save in not mount by kernel ?

My phone information:

all partition:

root@android:/ # ll /dev/block/
brw------- root root 254, 0 2012-11-30 22:08 dm-0
brw------- root root 7, 0 2012-11-30 22:07 loop0
brw------- root root 7, 1 2012-11-30 22:07 loop1
brw------- root root 7, 2 2012-11-30 22:07 loop2
brw------- root root 7, 3 2012-11-30 22:07 loop3
brw------- root root 7, 4 2012-11-30 22:07 loop4
brw------- root root 7, 5 2012-11-30 22:07 loop5
brw------- root root 7, 6 2012-11-30 22:07 loop6
brw------- root root 7, 7 2012-11-30 22:07 loop7
brw-rw---- root system 179, 0 2012-11-30 22:07 mmcblk0
brw------- root root 179, 32 2012-11-30 22:07 mmcblk0boot0
brw------- root root 179, 64 2012-11-30 22:07 mmcblk0boot1
brw------- root root 179, 1 2012-11-30 22:07 mmcblk0p1
brw------- root root 179, 2 2012-11-30 22:07 mmcblk0p2
brw------- root root 179, 3 2012-11-30 22:07 mmcblk0p3
brw------- root root 179, 4 2012-11-30 22:07 mmcblk0p4
brw------- root root 179, 5 2012-11-30 22:07 mmcblk0p5
brw------- root root 179, 6 2012-11-30 22:07 mmcblk0p6
brw------- root root 179, 96 2012-11-30 22:07 mmcblk1
brw------- root root 179, 97 2012-11-30 22:07 mmcblk1p1
drwxr-xr-x root root 2012-11-30 22:07 platform
drwxr-xr-x root root 2012-11-30 22:07 vold

mounted partition:

root@android:/ # mount|/system/xbin/busybox grep mmc
/emmc@android /system ext4 ro,noatime,user_xattr,commit=1,barrier=1,data=orde red,noauto_da_alloc 0 0
/emmc@usrdata /data ext4 rw,nosuid,nodev,noatime,user_xattr,barrier=1,data= ordered,noauto_da_alloc 0 0
/emmc@cache /cache ext4 rw,nosuid,nodev,noatime,user_xattr,barrier=1,data= ordered,noauto_da_alloc 0 0

had be linked partition:

root@android:/ # ll / |/system/xbin/busybox mmc
lrwxrwxrwx root root 1970-01-01 08:00 emmc@android -> /dev/block/mmcblk0p3
lrwxrwxrwx root root 1970-01-01 08:00 emmc@cache -> /dev/block/mmcblk0p4
lrwxrwxrwx root root 1970-01-01 08:00 emmc@ebr1 -> /dev/block/mmcblk0p1
lrwxrwxrwx root root 1970-01-01 08:00 emmc@fat -> /dev/block/mmcblk0p6
lrwxrwxrwx root root 1970-01-01 08:00 emmc@sec_ro -> /dev/block/mmcblk0p2
lrwxrwxrwx root root 1970-01-01 08:00 emmc@usrdata -> /dev/block/mmcblk0p5