IPod games are in the form of .ipg files, which are actually .zip archives in disguise. When unzipped, they reveal executable files along with common audio and image files, leading to the possibility of third party games. Apple has not publicly released a software development kit (SDK) for iPod-specific development. Apps produced with the iPhone SDK are compatible only with the iOS on the iPod Touch and iPhone, which cannot run clickwheel-based games. All iPods except for the iPod Touch can function in "disk mode" as mass storage devices to store data files but this may not be the default behavior.
IPhone to its customers on its website, acknowledging the effect that old batteries have on the iPhone's performance. The company offered $29 battery replacements as a solution. The first-generation iPhone and iPhone 3G have a fixed-focus 2.0-megapixel camera on the back for digital photos. It has no optical zoom, flash or autofocus, and does not natively support video recording. Video recording is possible on the first-generation iPhone and iPhone 3G via a third-party app available on the App Store or through jailbreaking. iPhone OS 2.0 introduced geotagging for photos. The iPhone 3GS has a 3.2-megapixel camera with autofocus, auto white balance,