Access "LG RH177 DVD Recorder" Hard drive

About a year ago the dvd drive in my LG RH177 DVD Recorder broke down. By making the internal HDD external and using the program from LG RH177 RH188 RH199 RH200 to access the data on the hard drive I'm able to copy all of the recorded data to my pc. I would like to reproduce that effect in a program of my own but i can't find anything on google on how to recognise what filesystem a hard drive is using. Programs like GParted cannot recognise the file system so it's not a typical one. I assume you can read the file structure from the beginning of the partition but I have little knowledge of that. Can anyone point me in the right direction? I have a basic knowledge of c and Java.