IPod that put "1,000 songs in your pocket." Apple did not develop the iPod software entirely in-house, instead using PortalPlayer's reference platform based on two ARM cores. The platform had rudimentary software running on a commercial microkernel embedded operating system. PortalPlayer had previously been working on an IBM-branded MP3 player with Bluetooth headphones. Apple contracted another company, Pixo, to help design and implement the user interface under the direct supervision of Steve Jobs. As development progressed, Apple continued to refine the software's look and feel. Starting with the iPod Mini, the Chicago font was replaced with Espy Sans. Later iPods switched
IPhone 5S iOS 7 and OS X Yosemite (version 10.10) noticeably departs from skeuomorphic elements such as green felt in Game Center, wood in Newsstand, and leather in Calendar, in favor of flat, colorful design. iOS 7 adds AirDrop, an ad-hoc Wi-Fi sharing platform. Users can share files with the iPhone 5 onwards, the iPod Touch (5th generation), iPad (4th generation) onwards, or iPad Mini (1st generation) onwards. The operating system also adds Control Center, a control panel accessed by swiping up from the bottom of the screen. Control Center contains a number of commonly used functions, such as volume and brightness