arstechnica has posted a fantastic editorial that I regrettably did not start reading earlier, documenting Google's Android OS throughout the ages, starting from the emulator-only m3 Android 0.5 builds, and how the operating system has evolved through the years into the household brand that it is today.
Clocking in at over 40,000 words and 26 pages, this is quite the article, but it's a very worthwhile read if you would like to see the OS at its infancy. I didn't get into the Android world until I bought a tablet that ran 2.3 and my first smartphone, the Galaxy Nexus, which ran 4.0. It's absolutely amazing to see what it was and to have seen every step since 4.0 to what it is now at 4.4.
arstechnica
