RecordNow and the *.gi ISO format

[ADROiT]

Hi. I just backed up a PS2 game for a friend the other day which he brought to me in *.gi format which is a format that I've never heard of before and it took me a while to discover that I needed to use RecordNow to write it to DVD.
Can anyone tell me anything about the *.gi format? Is it some special format for PS2 1:1 DVD copying that bypasses (or perfectly duplicates so as to make the copy exactly the same in every respect as the original) all copy protections, etc? Or is it just another ISO format that has to be hacked like any other ISO format such as CUE/BIN, etc?
(I'm using a Liteon DVD RW Dual Drive LDW-411S if that is of any importance (incase certain read/write feature/capabilities are required)).