Research about Android File Transfer

Research Findings:
1.  USB drivers for Android phones and tablets are needed for connecting our devices to the computer. This includes, using the device for development which requires Android SDK USB drivers, ADB and Fastboot drivers, transferring media content and files to your phone storage etc.
2.  Android doesn’t include a file manager app by default.
3.   With the Android device in its default MTP mode (PTP is also available, and USB mass storage may be available on older devices), it will appear in your Windows or Linux file manager window as a standard device.
4.  Older Android devices support USB mass storage for transferring files back and forth with a computer. Modern Android devices use the MTP or PTP protocols — you can choose which one you prefer.
5.  USB mass storage is the standard protocol used by flash drives, external hard drives, SD cards, and other USB storage devices. The drive makes itself completely available to the computer, just as if it were an internal drive.
6.  Apple’s Mac OS X is a holdout — it doesn’t include MTP support at all. Apple’s iPod, iPhone, and iPad use their own proprietary syncing protocol along with iTunes, so why would they want to support a competing protocol?
7.  Any software program that supports grabbing photos from a digital camera will support grabbing photos from an Android phone when you select the PTP mode. PTP was designed to be a standard protocol for communicating with digital cameras.
8.  your Android device will work with digital camera applications that support PTP but not MTP. Apple’s Mac OS X does support PTP, so you can use PTP mode to transfer photos from an Android device to a Mac over a USB connection without any special software.
9.  4GB limit is a filesystem limitation
10.  Whether you’re formatting an internal drive, external drive, USB flash drive, or SD card, Windows will give you the choice of NTFS, FAT32, and exFAT.
11.  Android is a Linux-based operating system
12.  Google’s Android developers could modify the Linux kernel to fit their needs. Linux gives the Android developers a pre-built, already maintained operating system kernel to start with so they don’t have to write their own kernel.
14.  The hardware abstraction layer (HAL) defines a standard interface for hardware vendors to implement and allows Android to be agnostic about lower-level driver implementations. The HAL allows you to implement functionality without affecting or modifying the higher level system. HAL implementations are packaged into modules (.so) file and loaded by the Android system at the appropriate time.
15.  Android is a mobile operating system (OS) currently developed by Google, based on the Linux kernel and designed primarily for touchscreen mobile devices such as smartphones and tablets.
16.  Android has the largest installed base of all operating systems of any kind. Android has been the best selling OS on tablets since 2013, and on smartphones it is dominant by any metric
17.  Android was unveiled in 2007, along with the founding of the Open Handset Alliance – a consortium of hardware, software, and telecommunication companies devoted to advancing open standards for mobile devices
18.  As of July 2013, the Google Play store has had over one million Android applications ("apps") published, and over 50 billion applications downloaded

Experience:
1. The storage is very limited, constrainted by storage size.

Tools:
File Explorer
Internal SD Card
External SD Card
Android Camera

Storage:
Internal Storage Options

Android Phones:
Sansung Galaxy S6
Android Version 5.1.1 Lollipop

System Architecture:
https://source.android.com/devices/

File Storage:
DCIM
Downloads

Image Transfer:
Preview App
Image Transfer App
FTU
Ext4

Good Tools:
Airdrop (Not Gallery)

Common Issues:
your device is rooted
Device Storage is too small
Hard to transfer media and movies to Computer
Pictures don't show in Image Transfer App
Which part is owned by Hardware Manufactor, Android Framework, and Application Developer ?
Many times doesn't recognize gestures.

References:
https://source.android.com/devices/
http://android.stackexchange.com/questions/48812/bypass-4gb-limitation-of-android-file-transfer
https://en.wikipedia.org/wiki/Android_(operating_system)