Abstract: Mechanisms are disclosed that allow for execution of unsigned content and the securing of resources in a closed system when such unsigned content is executing on the system. For example, an access layer is used between an operating system layer of the closed system and the actual unsigned content. This access layer may contain various sub-layers, such as a graphics layer, an audio layer, an input layer, and a storage layer. These layers can control access that the unsigned content can have to the native operating system layers and the associated resources of the closed system. By providing such an access layer, unsigned content, e.g., video games, can run on the closed system that is typically designed to run only signed content.

Abstract: Mechanisms are disclosed that allow for execution of unsigned content and the securing of resources in a closed system when such unsigned content is executing on the system. For example, an application programming interface is used between an access layer implementing unsigned content and an operating system of the closed system. The application programming interface may have sub-interfaces that correspond to sub-layers of the access layer, including a graphics sub-interface, an audio sub-interface, an input sub-interface, and a storage sub-interface. These sub-interfaces present access calls made by the sub-layers to the protected resources of the closed system. By providing the application programming interface, unsigned content, e.g., video games can run on a closed system that is typically designed to run only signed content.

Abstract: Mechanisms allow for execution of unsigned managed code graphic resource call in a closed system when such unsigned content is executing on the system. For example, a managed code graphic resource device is used between an application running unsigned content and a supervisor mode graphic resource device. A managed mode graphics device validates graphic resource calls made by the application. A managed mode graphics device manages resource calls by differentiating between calls that may be made directly to the supervisor mode graphics device, calls that may be pipelined for later action, and calls that may be made to an intermediate device.

Abstract: Mechanisms are disclosed that allow for execution of unsigned content and the securing of resources in a closed system when such unsigned content is executing on the system. For example, an application programming interface is used between an access layer implementing unsigned content and an operating system of the closed system. The application programming interface may have sub-interfaces that correspond to sub-layers of the access layer, including a graphics sub-interface, an audio sub-interface, an input sub-interface, and a storage sub-interface. These sub-interfaces present access calls made by the sub-layers to the protected resources of the closed system. By providing the application programming interface, unsigned content, e.g., video games can run on a closed system that is typically designed to run only signed content.

Abstract: A system may include a PWM (Pulse Width Modulator) configured to generate a PWM signal, a signal modifier configured to generate a modified PWM signal that includes a sampling activation signal having a different frequency than the PWM signal, fan drive circuitry configured to provide power to a fan in response to the modified PWM signal; and a sampling unit configured to sample a fan tachometer signal in response to an indication that the fan is currently powered.