Mobile OS System
Apple iOS
Based on Unix, Closed Source software, means no access to source code
if you’re writing applications for Apple’s iOS then you need to develop it on the iOS software developers kit, which is available exclusively on Mac OS X.
Google Andriod
Open Source OS/ based on Linux
Supported on many different manufacturer's device
can write applications for the Android operating system on Windows, on Mac OS X, and in the Linux operating system by using the Android software developers kit.
Windows OS
closed-source
based on the Windows NT kernel. You’ll find developers creating mobile applications and providing them on the Windows Store.
Device Displays & Technology
Calibration
On older devices we have these resistive touchscreens that require that you periodically calibrate the screen
Modern Capacitive touchscreen do not require calibration
Accelerometer (Motion sensor, detects orientation
Gyroscope ( detect any type of motion in all three different axes)
GPS
navigation
Wi-Fi calling
mobile devices to make calls over a Wi-Fi connection instead of using a traditional cellular phone company’s frequencies.
Virtual Assistant (Siri, OK google, Hey Cortana)
Production & Dev models
Applications for iOS are written on the Mac OS X operating system, and you would need Apple’s iOS software developers kit called Xcode.
Android. You can create applications on Windows, Mac OS X, and Linux by using the Android software developers kit, or Android Studio.
Windows Mobile, you would write all of your applications on a Windows 8.1 or a Windows 10 desktop using Microsoft’s Visual Studio.
In the US they have emergency alert *alert from the President etc)
Mobile Payment Service