DSM-G600, DNS-3xx and NSA-220 Hack Forum

I have a 1TB drive in a USB enclosure that I was using as a backup for the drives in the DNS 323. It was connected to the DNS 323 through its USB port. Now when I connect the USB enclosure directly to my Linux computer, the directory that automatically pops open is /media/d9ed81fb-4460-4d88-90bc-fd7002a036e6. Within that directory are 3 directories named backup, .lpd, and .systemfile. What is this?!

Running the 'df' command shows the following, which confuses me because I have a 1TB fully functioning drive when it's connected to the DNS 323 but now that it's connected to the Linux laptop it's only showing a 500M section:

/dev/sdb4     ext2    487M  5.5M  481M   2% /media/d9ed81fb-4460-4d88-90bc-fd7002a036e6

If I run a 'sudo fdisk -l /dev/sdb', I get the following output:

Disk /dev/sdb: 1000.2 GB, 1000204884992 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1          66      530113+  82  Linux swap / Solaris
/dev/sdb2             131      121404   974133405   83  Linux
/dev/sdb4              67         130      514080   83  Linux

I'd like to be able to both access and modify files on the USB enclosure by simply connecting it to my Linux laptop - but clearly something weird is going on here. Could somebody help explain what might be happening here and how to solve it?