The Samsung Galaxy S, released in June 2010, included a 4-inch screen with 480 x 800 resolution, 1500 mAh battery and 1 GHz Cortex-A8 processor. Out of the box, it ran Android 2.1 with either 8 or 16 GB of storage. It weighed 4.2 ounces.
Unlike its predecessor, the Galaxy i7500, the Galaxy S had front and rear cameras with 5 MP of resolution. The S also eliminated the directional pad, or D-pad, and instead used home, back and menu buttons. The Galaxy S evolved into the S2 in April 2011, the S3 in May 2012, the S4 in April 2013, the S5 in February 2014 and the S6 in April 2015.
The Galaxy S6 includes a 5.1-inch display with 2560 x 1440 resolution and 2.1 GHz Octa-Core processor, as of June 2015. It runs Android 5.1, Lollipop, with either 32 GB, 64 GB or 128 GB of internal memory. The 2600 mAh battery delivers up to 26 hours of talk time versus the maximum 6.3 hours from the original Samsung Galaxy S. The front-facing camera offers 5 MP of resolution, while the rear camera has been upgraded to 16 MP. The handset weighs 4.7 ounces and is 5.59 inches long, 2.76 wide and 0.28 inches deep.