Problem with 4TB WD Mybook to Mac mini

I recently bought the WD Mybook Studio 2 with 4TB size (with RAID 0 configuration with HFS+ file system). I connected to my Mac Mini Power PC G4 with Tiger OS (10.4.11). It is very strange that I can only see 2TB of the disk not 4 but if I change the RAID configuration to RAID 1 I can see 1.86TB and if I took the drive to connect to my Window PC I can see it as 3.8TB. It seems like 2TB is the maximum size that my Mac mini can see, is there any possible way to solve this?? Please help.

A 4TB drive means that there are two physical 2TB volumes. The volumes must be in RAID0 to have that kind of capacity. If you changed the RAID configuration to RAID1, then you effectively halve the capacity because one drive is simply a mirror of the other. Not sure why it happened to change to 3.8TB available on your Windows machine unless of course you happened to switch it to RAID0 and didn't realize what you had done. Your Mac Mini shouldn't have a problem addressing that space, provided the drive is configured properly.

Thank you for your quick reply cwa107. I've already configured it as the RAID0 and mac mini only see 2TB not 4TB as screen-shot attached. Sorry to confused you. When I connect to the window PC I set to RAID0 and I can see it as 3.8TB so this mean the problem is not cause by faulty disk.