Another way to appreciate the significance of Android is to take a historical perspective. In the early days of PCs, the operating system was DOS. This presented some interesting challenges to application developers, as DOS provided a minimal number of services. The result was that every application needed a complete framework to provide the full functionality that was required. For example, a word processing program would need to have a driver for every imaginable printer. This was a major headache for developers and a serious ongoing maintenance problem. The solution came in the early 1990s with the release of Windows. Or, rather, the development of Windows 3.0. Although we think of Windows as being primarily a GUI, it really is much more than that. Nowadays, a word processor just talks to a logical printer. The manufacturer of the printer hardware simply needs to provide a Windows driver and everything works together properly. In some respects, a similar situation exists today when developers want to deploy Linux for embedded applications. Android is the enabler for a broad application developer base, a complete stack on top of the Linux kernel.