I'm about to install an SSD and a larger HDD in a new mid-2012 non-retina MBP. I'll preface my actual question with a brief summary of what I've concluded from reading thus far, in case it helps someone with similar plans, so please reply with any corrections. Where to install the SSD and HDD It sounds like the consensus of opinion is that the SSD should go in the old HDD bay and the secondary drive -- in my case a 1TB 7200rpm HDD -- should go in the optical drive bay. I've read that SMS works in both channels but for some reason booting from the optical drive SATA channel is unreliable -- or so they say. I'd rather mount the HDD in the actual HDD bay because of the shock mounts and the assumption that HDD bay is better designed for cooling an HDD, but I'll trade reliable booting for either of those. In what order to install this stuff I understand that Bootcamp needs the optical drive for installing Windows (v8 in my case) so I'll start with just the SSD installed. I'll use CarbonCopy to move OSX to the SSD from the stock HDD in a USB3 dock. Then do the Bootcamp thing and install Windows 8. It's a 256GB SSD so I'll split it. I'm in the dark about how many partitions the Mac can handle but I'm assuming OSX needs 2 and Windows 8 uses 3, so, well... that's unknown territory for me. Now to my question... Can I share the HDD data drive between Windows and OSX, or should I split the HDD and let each OS have its own data partition? Except for my music library I'll be mostly using each OS for different purposes, so sharing isn't essential if it's a bad idea. On the other hand, I'd rather share the music and have the full 1TB of space for whichever applications need it. Since the HDD is a 1TB drive I can't use FAT32 so I assume that if I want both OS's to share it I'll have to use 3rd party software to make it readable by OSX or Windows. Which OS should get native access vs a driver? I don't know how well OSX and Windows get along when sharing a data; does either OSX change the data files in ways that make this more trouble than it's worth? For one somewhat extreme example, it would be ideal if iTunes in OSX and iTunes in Windows could both share the same music folder but what's the likelihood of this working?