The device can also be used as a Wi-Fi connection based portable Internet browsing platform. It uses Apple's iOS (formerly called iPhone OS) operating system which is based on the other operating system developed by their company, the Mac OS for Machintosh. It can execute a large number of applications, as long as they are checked and approved by Apple, and obtained through their online webstore called the AppStore.
You can still execute third party applications which were not checked by Apple, but doing so may cause sever software malfunctions which will not be covered by your iPhone's warranty. The control of the iPhone 3GS is built around the capacitive multi touch based liquid crystal display. The 3.5 inch screen is suitable for games, web browsing and movies, because of the large area it covers on the front of the device.
The screen was intended for bare finger usage, so normal styluses and gloves will not work because they are not able to produce the required amount of electrical conductivity in order for the screen to register the touch as a screen touch event. The iPhone 3GS's improvements from the previous iPhone primary consist of technical upgrades, hardware changes regarding the device's speed and performance ( the "S" in "iPhone 3GS" comes from "Speed" ). Other changes have been made to however, like the new Voice Control, higher resolution camera which can now perform video recording, improved HSDPA 7.2 Mbit/s support for downloading (the upload remained at 384 Kbps because Apple didn't implement the HSUPA protocol). The device was launched in the United States, Canada, and six other European countries on 19 June 2009, and in Japan and Australia one week later, on 26 June, 2009.
The worldwide release took place in July and August of 2009. The display on the iPhone 3GS is designed by Apple, but manufactured by LG. It contains a multi touch capacitive screen with a density of 163 ppi (pixel per inch) and dimensions of 480x320. There are some improvements over its predecessor, like the 24-bit color emulation (18-bit color display plus dithering) for a more rich colored display, and the oleophobic coat that covers the entire screen, and reduces the fingerprints on it. Although there still are some fingerprints on the screen after a session of using the phone, their number is very small compared with a screen without the coat.