The iPod Classic 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 September 5, 2007 (styled as iPod classic); prior to this, iPod Classics were simply referred to as "iPods".

User interface

. The buttons are:

• Menu: to traverse backwards through the menus, toggle the backlight on older iPods, and jump to the main menu on newer iPods
• Center: to select a menu item
• Play / Pause: this doubles as an off switch when held
• Skip Forward / Fast Forward
• Skip Backwards / Fast Reverse

Operating system and firmware

iPod's operating system is stored on its dedicated storage medium. An additional NOR flash ROM chip (either 1 MB (1 MiB) or 512 KB (512 KiB)) contains a bootloader program that tells the device to load its OS from the storage medium. Each iPod also has 32 MiB of RAM, although the 60 and 80 GB fifth generation, and the sixth generation models have 64 MiB. A portion of the RAM is used to hold the iPod OS loaded from firmware, but the majority of it serves to cache songs from the storage medium. For example, iPod could spin its hard disk up once and copy approximately 30 MB of upcoming songs into RAM, thus saving power by not requiring the drive to spin up for each song. Rockbox and iPodLinux offer open-source alternatives to the standard firmware and operating system, respectively. However, at the current time these are both unavailable for use with the 6th generation iPod Classic due to encryption used on the official firmware.

Additional features

In March 2002, Apple added limited PDA-like functionality: text files can be displayed, while contacts and schedules can be viewed and synchronized with the host computer. Some built-in games are available, including Brick (a clone of Breakout), Parachute, Solitaire, and Music Quiz. A firmware update released in September 2006 brought some extra features to fifth generation iPods including adjustable screen brightness, gapless playback, and downloadable games (available for purchase from the iTunes Store).

First generation

On March 20, 2002, Apple introduced a 10 GB model of the first generation iPod for US$499. vCard compatibility was added, as well, allowing iPods to display business card information synced from a Mac.