Hello World, I couldn't resist, this being my first post. I recently picked up a used copy of Logic 5.0 Platinum in hopes to upgrade to Logic Studio. What I received was a few boxes and a key. The two boxes are labeled PTHD EXT & ESB TDM. These are hybrid disks but have licenses for the Mac. What Mac OS will these run on and what older PT version? Would it be worth it to invest in an older PT HD/Mac system? Any suggestions for I/O hardware?. I am a computer tech for a large telecom and working on DAW's is my hobby/sideline. I currently have the following rigs. A Macbook with Reason, Live and Pro Tools M-Powered and two PC's. One is running Sonar 6 on x64 and the other is running Cubase SX3 and Komplete 3. I enjoy using Macs the most and Reason for personal use but I like to tinker and learn older technology so I can understand where some of my friends and clients are coming from. Thanks! Jeff