WD hard drive partition mounting: newbie

Sorry guys I’m useless at this. I’ve followed various guides on how to recover files from the my seemingly defunct NAS drive( white light MyBOOK World). I have the ubuntu on disc and it’s working well. I’ve got the disc drive plugged into a usb port with an adaptor. When i go through the steps described in various poss, i always gets something in teh following vain:

root@ubuntu:/home/ubuntu# sudo mdadm --assemble /dev/md4 /dev/sdf4
mdadm: no recogniseable superblock on /dev/sdf4
mdadm: /dev/sdf4 has no superblock - assembly aborted

Now i know nothing about linux so please double explain things if you kind enough to help:

I think the forum wise tend to ask for the result of this command:

root@ubuntu:/home/ubuntu# fdisk -l

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x87ac63e6

Device Boot Start End Blocks Id System
/dev/sda1 63 80324 40131 de Dell Utility
/dev/sda2 * 81920 34832383 17375232 7 HPFS/NTFS/exFAT
/dev/sda3 34832384 1953521663 959344640 7 HPFS/NTFS/exFAT
Note: sector size is 4096 (not 512)

Disk /dev/sdf: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 15200 cylinders, total 244190646 sectors
Units = sectors of 1 * 4096 = 4096 bytes
Sector size (logical/physical): 4096 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x0001cf00

Device Boot Start End Blocks Id System
/dev/sdf1 64320 3984191 15679488 fd Linux raid autodetect
/dev/sdf2 3984192 4498175 2055936 fd Linux raid autodetect
/dev/sdf3 4498176 6474175 7904000 fd Linux raid autodetect
/dev/sdf4 6474176 1953520064 3493216260 fd Linux raid autodetect
root@ubuntu:/home/ubuntu#

I believe it is the sdf4 partition I am trying to access, right?

Thanks in advance:

What’s the output from:

sudo mdadm --examine /dev/sdf4

Reference:
https://blog.sleeplessbeastie.eu/2012/05/08/how-to-mount-software-raid1-member-using-mdadm/

Device Boot Start End Blocks Id System
/dev/sdf1 64320 3984191 15679488 fd Linux raid autodetect
/dev/sdf2 3984192 4498175 2055936 fd Linux raid autodetect
/dev/sdf3 4498176 6474175 7904000 fd Linux raid autodetect
/dev/sdf4 6474176 1953520064 3493216260 fd Linux raid autodetect
ubuntu@ubuntu:~$ sudo mdadm --examine /dev/sdf4
mdadm: No md superblock detected on /dev/sdf4.
ubuntu@ubuntu:~$

What’s the output from:

cat /proc/mdstat

ubuntu@ubuntu:~$ cat /proc/mdstat
Personalities :
unused devices:
ubuntu@ubuntu:~$