It always seems that as hard drive technology matures and capacities grow, we learn that the supporting hardware and software aren't caught up. Do you remember getting your first hard drive that was larger than 137GB?
Older machines could not recognize hard drives with volumes exceeding 137GB. This was due to the BIOS using a 28-bit boundary. In order to see larger capacities, the BIOS needing to support 48-bit addressing. This would require a BIOS upgrade (if applicable and available) to exceed the limitation.
Once your hardware used 48-bit addressing, your next hurdle was the operating system. Your version of Windows (2000 or XP) would require an upgrade to a service pack (minimal SP3 and SP1 respectively).
Linux also needed a kernel upgrade to use the larger drives. Even Apple had requirements: Mac OS 10.2 or later and the system BootROM must support the drive.
Now that everyone has replaced their legacy hardware and has upgraded to newer operating systems, it's time to retire that 500GB hard drive and go out and get a 2.5TB or 3TB drive. The only problem is, you guessed it, your hardware is once again legacy.
At the present time, most computers don't support anything beyond 2.19TB. It's the same problem all over again. You will require a specific operating system and specific hardware. Windows XP is out of the picture. It uses legacy MBR (Master Boot Record) partitioning to access hard disks, which limits the readable capacity to 2^32 * 512-bytes, or 2,199,023,255,552 bytes. Sorry XP, you tiger now!
You will need an operating system that support GPT (GUID Partition Table), such as Windows Vista, Windows 7, or MAC OS 10.5. According to Western Digital, Linux solutions are available, but you need to contact your operating system provider for support. I'm having some trouble finding documentation regarding Linux support for the larger capacties.
Once you have GPT support, you can then use your larger than 2.19TB drive... as secondary storage only. If you want to boot from a behemoth drive, your motherboard must have UEFI (Unified Extensible Firmware Interface) instead of BIOS and your OS must be 64-bit. Even Windows 7 32-bit cannot boot from one of these large drives.
Western Digital seems to be pioneering the launch of these extraordinarily sized hard drives. With their 2.5TB and 3.0TB drives, they're including an add-on card to help get around some of the obstacles for using their drives. On their site, they have a nice little chart summarizing what was said above in regards to operating system support. Here's a nice little review on the 3TB models from Anandtech.com
Additionally, Asus has released a software solution to get those of us not wanting to upgrade yet access to the >2.19TB spectrum. As said on TomsHardware.com, "The drawback is that the software only works with Asus motherboards and doesn't create a bootable partition..."
To sum it up, if you have the need for more storage, you're probably going to need some upgrades.