Android BUILT-IN SD device node where and FileSystem Type?

Question

look this information , My Android Device is larger Flash, it use built-in sd card. I can't fond it's device node , and dont' konw it's file system type.

root@android:/dev # mount                                                      
rootfs / rootfs rw 0 0
tmpfs /dev tmpfs rw,nosuid,relatime,mode=755 0 0
devpts /dev/pts devpts rw,relatime,mode=600,ptmxmode=000 0 0
proc /proc proc rw,relatime 0 0
sysfs /sys sysfs rw,relatime 0 0
tmpfs /mnt/asec tmpfs rw,relatime,mode=755,gid=1000 0 0
tmpfs /mnt/obb tmpfs rw,relatime,mode=755,gid=1000 0 0
/dev/block/nandd /system ext4 rw,nodev,noatime,user_xattr,barrier=0,data=ordered 0 0
/dev/block/nande /data ext4 rw,nosuid,nodev,noatime,user_xattr,barrier=0,journal_checksum,data=ordered,noauto_da_alloc 0 0
/dev/block/nandh /cache ext4 rw,nosuid,nodev,noatime,user_xattr,barrier=0,journal_checksum,data=ordered,noauto_da_alloc 0 0
/dev/block/vold/93:64 /mnt/sdcard vfat rw,dirsync,nosuid,nodev,noexec,relatime,uid=1000,gid=1015,fmask=0702,dmask=0702,allow_utime=0020,codepage=cp437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/vold/93:64 /mnt/secure/asec vfat rw,dirsync,nosuid,nodev,noexec,relatime,uid=1000,gid=1015,fmask=0702,dmask=0702,allow_utime=0020,codepage=cp437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro 0 0
tmpfs /mnt/sdcard/.android_secure tmpfs ro,relatime,size=0k,mode=000 0 0
root@android:/dev # 

and

root@android:/dev # ls /dev/block/                                             
loop0 loop2 loop4 loop6 nanda nandc nande nandg nandi ram1  
loop1 loop3 loop5 loop7 nandb nandd nandf nandh ram0  vold/ 
root@android:/dev # ls /dev/block/  

Cant' fond device node.

Let's see other device with no built-in sd:

/ # ls /dev/block/mmcblk0
/dev/block/mmcblk0
/ # fdisk /dev/block/mmcblk0

The number of cylinders for this disk is set to 80672.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): p

Disk /dev/block/mmcblk0: 3965 MB, 3965190144 bytes
3 heads, 32 sectors/track, 80672 cylinders
Units = cylinders of 96 * 512 = 49152 bytes

              Device Boot      Start         End      Blocks  Id System
/dev/block/mmcblk0p1              22       80662     3870720   b Win95 FAT32

Command (m for help): 

where is device node build-in sd ? which type is it's file System ?

Answer 1

Android supports extended secondary storage in the form of external sd-cards. However certain device manufacturers provide on-board flash of large capacity and map (a part of) it to /mnt/sdcard. This is NOT a real sd-card and hence no distinct mmc device is listed by the kernel specific to the sd-card. Rather the volume daemon(vold) is configured to handle the fake "sd-card" simulated using on-board NAND-flash.

The use of vold is evident by the following line in the list of active mounts

/dev/block/vold/93:64 /mnt/sdcard vfat rw,dirsync,nosuid,nodev,noexec,relatime,uid=1000,gid=1015,fmask=0702,dmask=0702,allow_utime=0020,codepage=cp437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro 0 0

Configuring vold is achieved by editing vold.fstab (usually found in /system/etc/ on Android). Here is how external storage is supposed to be configured on Android.