US 8,286,195 B2Granted

Controlling hardware across two or more simultaneously running operating systems

AssigneeMicrosoft Corporation

InventorsJay Finger, Jeffrey Alan Davis, Brian Douglas King, John A. Yovin, Praful Prataprai Chavda

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Abstract

A computing device has two or more software stacks, each stack simultaneously running a different operating system. Only one enabled operating system at a time has control of hardware resources of the computing device. Each disabled operating system has its device drivers disabled. The drivers may be disabled by stopping device driver messages to devices at a firmware layer unassociated with any operating system. The drivers may be disabled by having their associated operating system dynamically unload them when the operating system is disabled. In some instances, the drivers may be modified to include a “stop” control that tells the driver to stop communicating with its associated device, and a “resume” control that tells the driver to resume communication. When an operating system is disabled, the operating system may send a “stop” message to its device drivers. Drivers associated with messages passed between operating systems may remain enabled.

Claims19

Dependent claims

A computer-enabled method for controlling hardware shared by multiple operating systems, the method comprising:

running a first operating system on a first central processing unit (CPU) associated with a computing device, the first operating system having a first set of device drivers, the first set of device drivers enabled such that they access the shared hardware, the shared hardware comprising a hardware resource;
running a second operating system on a second CPU associated with the same computing device, the second operating system having a second set of device drivers, the second set of device drivers disabled such that they do not access the shared hardware;
such that the first and second operating systems run simultaneously;
detecting, by the hardware resource, an input for the second operating system;
and
switching operating system hardware control, comprising:
disabling the first set of device drivers, wherein at least a portion of the first set of device drivers each have a stop communication control function that stops a respective device driver of the first set of device drivers from communicating with the shared hardware;
and wherein disabling the first set of device drivers comprises sending a stop message to the stop communication control function of the at least a portion of the first set of device drivers;
and
enabling the second set of device drivers such that they access the shared hardware;
the second operating system using the second set of device drivers to access the input;
and
the second operating system processing the input.

10 more elements

A computing device, comprising:

at least one hardware device;
a first operating system on a first central processing unit (CPU) having a first set of device drivers operationally able to access the hardware device;
a second operating system on a second CPU having a second set of device drivers, operationally able to run simultaneously with the first operating system;
the second set of device drivers operationally able to access the hardware device;
an input detector operationally able to detect an input of the hardware device;
an operating system switcher, comprising:
a first operating system driver disabler;
a first operating system driver enabler;
a second operating system driver disabler;
and
a second operating system driver enabler;
wherein when the input detector detects an input associated exclusively with the second operating system, if the second operating system is disabled, the operating system switcher disables the currently enabled first operating system that is enabled to access the hardware device through use of at least the first set of communication device drivers and enables the second operating system associated with the input to have access to the hardware device through use of at least the second set of device drivers;
wherein at least one communication device driver of the first set of communication device drivers comprises a stop communication control function that stops the at least one communication device driver from communicating with the hardware device;
and wherein the operating system switcher disables the currently enabled first operating system at least by sending a stop message to the stop communication control function of the at least one communication device driver of the first set of communication device drivers.

11 more elements

A computer-implemented method to allow an optical disk drive associated with an optical disk system to play optical disks with multiple formats comprising:

on a first central processing unit (CPU), running a first operating system able to play an optical disk in the optical disk drive when the optical disk is in a first format;
on a second CPU, simultaneously running a second operating system able to play the optical disk in the optical disk drive when the optical disk is in a second format;
in response to a message that a second format disk has been detected, if the first operating system is enabled, then enabling the second operating system, comprising:
1) disabling first operating system access to shared hardware resources comprising the optical disk drive at least by disabling one or more device drivers for the first operating system that are operationally able to access the shared hardware resources comprising the optical disk drive, wherein at least one device driver of the one or more device drivers for the first operating system has a stop communication control function that stops the at least one device driver of the one or more device drivers for the first operating system from communicating with the shared hardware resources;
and wherein the disabling the first operating system access to shared hardware resources further comprises sending a stop message to the stop communication control function of the at least one device driver of the one or more device drivers for the first operating system;
2) sending a message to the second operating system, and
3) enabling the second operating system access to the shared hardware resources comprising the optical disk drive at least by enabling one or more device drivers for the second operating system that are operationally able to access the shared hardware resources comprising the optical disk drive;
in response to a message that a first format disk has been detected, if the second operating system is enabled, then enabling the first operating system, comprising:
1) disabling second operating system access to shared hardware resources comprising the optical disk drive at least by disabling the one or more device drivers for the second operating system that are operationally able to access the shared hardware resources comprising the optical disk drive,
2) sending a message to the first operating system, and
3) enabling the first operating system access to the shared hardware resources comprising the optical disk drive at least by enabling the one or more device drivers for the first operating system that are operationally able to access the shared hardware resources comprising the optical disk drive;
and wherein the enabled first or second operating system is used to play the optical disk in the optical disk drive.

9 more elements

Dependencies are inferred from the claim text.