IOS DEVICES

Devices

 

Every iOS device (like every mobile device) is a computer, composed of a set of
hardware components: processor, memory, input/output (I/O) devices (such as
a keyboard, touchpad, and screen), and storage (discs and flash, for example).
Unlike Android devices, the hardware configuration is controlled completely
by Apple, so there are just four main variations of devices to consider when
developing iOS apps:
? iPhone (of course)
? iPod Touch
? iPad
? iPad mini
Like other smart devices, iOS devices also come with several built-in hardware
components, such as the following:
? Cameras (front and back facing)
? Audio inputs and outputs
? GPS
? Accelerometer
? Light sensor
Apple has yet to come out with a near-field communications-enabled device
(or NFC-enabled device) but was recently awarded a patent for NFC-enabled
data synching technology. For the inside story from Apple, check the link
labeled NFC at www.dummies.com/go/iosprogramminglinks.
Unless you really and truly want to, you’ll never see iOS, the operating
system, nor will your program. However, you must recognize that it’s
there — the iOS framework does certain things in certain ways because it
runs on iOS. For example, every running program is assigned a process.
When an iOS app starts, an iOS process becomes active. This process takes
over an area of the screen on the device and allows the user to interact with
the application. If another application starts, it pushes the first application
to the background. At this point, the process assigned to the first application
may be (arbitrarily) terminated by the operating system to save device
resources. Before this happens, the iOS runtime notifies the application to
save its state.
This iOS operating system is the OS that manages the device on which your
apps run. A different operating system manages the personal computer on
which you develop apps (the Macintosh OS or OS X).