HardwareItself, such as someEmbedded system , do not need an operating system, and access hardware directly.
Browser used by web-based software.The browser itself runs on a system platform, but the applications in the browser do not care.
The application program can support some scripting languages, such as macros in Excel.
A software framework that provides some functions.
As a service cloud computing platform.Social networks such as Twitter and Facebook can also be regarded as a development platform.
Virtual machine (VM), such as Java virtual machine.Applications are compiled into byte codes similar to machine codes and can be executed by virtual machines.
The virtualized version of the full system.Includes virtual hardware, operating system, software, and storage.