The hard drive-based iPod is a music player from Apple Inc. It can play music in MP3, WAV, AAC, AIFF and Apple Lossless. Besides playing music, the iPod is used as an external hard drive. An iPod is characterized by its compact size, its simple user interface based on a central scroll wheel and a fast FireWire or USB 2-connection with which one can transfer data at speeds up to 400 Mbit / second.
Since it was first announced in October 2001, the iPod only available with a 5 GB hard drive. A 10GB version was announced in March 2002 and July 2002, a 20 GB model was announced. Here, both 10 – and 20 GB models improved with such a touch-screen (instead of moving) roller wheels. Firmware updates have since added the iPod PDA-like features.