Methods and systems for running multiple operating systems in a single mobile device

• US 8,090,938 B2
• Filed: 08/28/2008
• Issued: 01/03/2012
• Est. Priority Date: 07/07/2004
• Status: Active Grant

• Current Assignee: Intellectual Ventures Holding 81 LLC (Intellectual Ventures LLC)
• Original Assignee: Intellectual Ventures Fund 63 LLC (Intellectual Ventures LLC)
• Inventors: Xu, Yongyong
• Primary Examiner(s): Bae, Ji H
• Application Number:
  US12/200,573
• Publication Number:
  US 20090037649A1
• Time in Patent Office: 1,223 Days
• Field of Search: None
• US Class Current: 713/100
• CPC Class Codes: G06F 11/1446 Point-in-time backing up or restoration of persistent data
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 12/14 Protection against unauthorised use of memory or access to memory
• CPC Class Codes: G06F 9/4401 Bootstrapping security arrangements therefor G06F21/57
• CPC Class Codes: G06F 9/4406 Loading of operating system
• CPC Class Codes: G06F 9/441 Multiboot arrangements, i.e. selecting an operating system to be loaded
• CPC Class Codes: G06F 9/45545 Guest-host, i.e. hypervisor is an application program itself, e.g. VirtualBox
• CPC Class Codes: G06F 9/544 Buffers; Shared memory; Pipes

Abstract

Methods and systems for running multiple operating systems in a single embedded or mobile device (include PDA, cellular phone and other devices) are disclosed. The invention allows a mobile device that normally can only run a single operating system to run another operating system while preserving the state and data of the original operating system. Guest OS is packaged into special format recognizable by the host OS that still can be executed in place by the system. The Methods include: Change the memory protection bits for the original OS; Fake a reduced physical memory space for guest OS; Use special memory device driver to claim memories of host OS; Backup whole image of the current OS and data to external memory card.

Claims

1. A method, comprising:

protecting at least a first portion of a memory from access, wherein the memory is configured to store a first operating system and a second operating system, wherein the second operating system is configured to be executed by the first operating system, and wherein the at least first portion of the memory is protected from access such that the second operating system cannot access the first portion of the memory;

storing a state of the first operating system and at least one memory attribute associated with the first operating system in the first portion of the memory;

loading the second operating system into a second portion of the memory;

transferring control to the second operating system;

executing an exit code to restore the first operating system based at least in part on the stored state of the first operating system and the stored memory attributes associated with the first operating system, wherein storing a state of the first operating system comprises;

copying and moving the state from a lower memory address space to an upper address space; and

faking a reduced memory environment.

2. The method of claim 1, wherein storing a state of the first operating system comprises manipulating at least one memory protection bit of a mobile device memory.

3. The method of claim 2, wherein manipulating memory protection bits comprises changing at least one attribute from read/write to read-only.

4. The method of claim 2, wherein manipulating memory protection bits comprises making at least one page of the mobile device memory inaccessible.

5. The method of claim 1, wherein executing an exit code to restore the first operating system comprises:

reverting the state from the upper address space to the lower address space; and

restoring the reduced memory environment to a previous memory environment.

6. The method of claim 1, wherein faking the reduced memory environment comprises modifying at least one system register to report the reduced memory environment.

7. The method of claim 1, wherein faking the reduced memory environment comprises changing a memory detection module to use the reduced memory environment.

8. The method of claim 1, wherein faking the reduced memory environment comprises generating the reduced memory environment by disabling at least one memory bank to make them invisible.

9. The method of claim 1, wherein storing the state of the first operating system comprises using a memory device driver to claim memory blocks containing the state of the first operating system.

10. The method of claim 9, wherein claiming memory blocks containing the state of the first operating system comprises making said memory blocks un-modifiable.

11. The method of claim 9, wherein claiming memory blocks containing the state of the first operating system comprises making the memory blocks inaccessible.

12. The method of claim 9, wherein the memory device driver is a kernel mode driver that prevents the claimed memory blocks from being used by both kernel and user space processes.

13. The method of claim 1, wherein storing the state of the first operating system comprises backing up the state of the first operating system to an external memory card.

14. The method of claim 13, wherein the external memory card comprises one of a Compact Flash (CF) memory card, a Secure Digital (SD) memory card, or an MMC card.

15. The method of claim 1, wherein the state of the first operating system comprises a current input/output (IO) state and current registers of a mobile device.

16. The method of claim 1, wherein transferring control to the second operating system comprises restricting simultaneous access to the first operating system and second operating system.

17. The method of claim 1, further comprising facilitating access by an application executed by the second operating system to data associated with the first operating system.

18. The method of claim 1, further comprising storing a state of the second operating system into the second portion of the memory.

19. A non-transitory computer-readable medium having computer-executable instructions stored thereon, the instructions comprising:

instructions to protect at least a first portion of the memory from access, wherein the memory is configured to store a first operating system and a second operating system, wherein the second operating system is configured to be executed by the first operating system, and wherein the at least first portion of the memory is protected from access such that the second operating system cannot access the first portion of memory;

instructions to store a state of the first operating system and at least one memory attribute associated with the first operating system in the first portion of the memory;

instructions to load the second operating system into a second portion of the memory;

instructions to transfer control to the second operating system;

instructions to execute an exit code to restore the first operating system based at least in part on the stored state of the first operating system and the stored memory attributes associated with the first operating system, wherein storing a state of the first operating system comprises;

copying and moving the state from a lower memory address space to an upper address space; and

faking a reduced memory environment.

20. The system of claim 19, wherein at least one of the first operating system or second operating system is a mobile operating system component.

21. A device, comprising:

a memory configured to store a first operating system and a second operating system, wherein the second operating system is configured to be executed by the first operating system;

a processor operatively coupled to the memory and configured to;

protect at least a first portion of the memory from access such that the second operating system cannot access the first portion of memory;

store a state of the first operating system and at least one memory attribute associated with the first operating system in the first portion of the memory;

load the second operating system into a second portion of the memory;

transfer control to the second operating system;

execute an exit code to restore the first operating system based at least in part on the stored state of the first operating system and the stored memory attributes associated with the first operating system, wherein storing a state of the first operating system comprises;

copying and moving the state from a lower memory address space to an upper address space; and

faking a reduced memory environment.

22. The device of claim 21, wherein the device comprises one of a PDA, a handheld device, a cellular phone, or an embedded device.