Smartphone touchscreen device with a slide-out physical keyboard. The first Android device, the HTC Dream, was released in September 2008. Although Android's adoption was relatively slow at first, it started gaining widespread popularity in 2010, and in early 2012 dominated the smartphone market share worldwide, which continues to this day. Android and iPhone devices popularized the smartphone form factor based on a large capacitive touchscreen, and led to the decline of earlier, keyboard- and keypad-focused platforms. Microsoft, for instance, discontinued Windows Mobile and started a new touchscreen-oriented OS from scratch, called Windows Phone. Nokia abandoned Symbian and partnered with Microsoft to
Distributed operating system and functionality required of an OS but adds attributes and particular configurations to allow it to support additional requirements such as increased scale and availability. To a user, a distributed OS works in a manner similar to a single-node, monolithic operating system. That is, although it consists of multiple nodes, it appears to users and applications as a single-node. Separating minimal system-level functionality from additional user-level modular services provides a “separation of mechanism and policy.” Mechanism and policy can be simply interpreted as "what something is done" versus "how something is done," respectively. This separation increases flexibility and scalability. At