Forum Moderators: travelin cat
Most external hardware will work on the Mac if it is FireWire or USB. As for internal, it depends...most SATA hard drives will work fine. Macs already have a DVD+R DL/DVD±RW/CD-RW optical drive in by default.
You can find specs here for Apple products that may answer specific questions:
[support.apple.com...]
Most distributors of hardware will tell you if the hardware you've got is Mac compatible. But if they say "No, it's not," sometimes they mean they just don't support Mac, so it's Plug and Play at your own risk.