The iPod Classic (trademarked as iPod classic and known before its sixth generation as simply the iPod) is a portable media player marketed by Apple Inc. To date, there have been six generations of the iPod Classic, as well as a spin-off (the iPod Photo) that was later re-integrated into the main Classic line. All generations use a 1.8-inch hard drive for storage. The "Classic" retronym was introduced with the introduction of the sixth-generation iPod Classic on 5 September 2007; prior to this, an iPod Classic was simply referred to as an iPod.