question about accessing different hard drives with different operating systems...

[HopeHoops]

3. Are you looking to replace the .45TB drive with the 1.5TB one or just access the latter?

Any new drive you buy should work interchangeably with any OS on any machine. If you're using the same machine for a dual-boot, as it seems, and you just want extra storage, it shouldn't matter which OS you boot into. The 1.5TB will be visible and available for full access (unless you put access restrictions on something - that's NOT cross-platform).

That said, if you intend to install programs on the 1.5TB, I would suggest partitioning it based on your needs, but Ubuntu is lean and Windows (any flavor) is bloated on install, as are the applications, so I would suggest a 1/3-2/3 partition (adjusted as you see the need). Unless you direct them otherwise, both partitions should appear under either OS, but you just accept that and ignore the irrelevant one. You might also consider four partitions - U-Program, U-Data, W-Program, W-Data. That's a personal preference. It won't impact performance.