Partition problem.

[alldogship]

I got a 30Go Video ipod 5.5gen and I have to use the 2048-byte sectors to put it in FAT32 since I got a mac. The strange thing I found before reformating was that the disk was splitted in two 15Go partitions. I didn't touch it, continued with the install and everything was fine except the loss of half my disk space. Any solutions or is it supposed to be like that?