Disc Drives
Disc drives are used to allow CDs, DVDs, BluRays to be read by the computer. You connect the disc drive to the computer via USB or attached to the motherboard via cables. They are a processing device for the computer.
Data Storage Devices
Data storage devices hold information in them. They are plugged into the computer via the USB ports and can be either in USB 2.0 or USB 3.0. They are classified as a storage device.