IPod Software

iPod Software is the real-time operating system used on all iPod devices, with the exception of iPod shuffle (1st generation) and all iPod touch models. It has been referenced as "RetailOS" internally.

iPod Software was built on the foundation of Pixo OS, an embedded operating system toolkit developed by PIXO, Inc. to create user interfaces for low-end ARM devices. Pixo OS, itself, is based on RTXC 3.2. Pixo OS was licensed by Apple during development of iPod with scroll wheel (1st generation), later acquiring full rights to the operating system. Over time, the operating system was extended with a considerable number of features, including video playback, video recording, multitouch, and Bluetooth.

The operating system is entirely implemented in a single binary, and there is no memory space separation between the kernel, user interface, and other components. While eApps (games) are implemented as separate binaries that are installed to the iPod's storage, they are executed within the same memory space as the kernel.

On iPod nano (2nd generation) and newer, iPod Software is booted by a variant of iBoot similar to that of the first-generation iPhone, and makes use of a driver for the PowerVR GPU core.