Method and apparatus for swapping a computer operating system

• US 6,175,917 B1
• Filed: 04/23/1998
• Issued: 01/16/2001
• Est. Priority Date: 04/23/1998
• Status: Expired due to Term

• Current Assignee: Avaya Incorporated
• Original Assignee: VPNet Technologies, Inc. (Avaya Incorporated)
• Inventors: Jones, Russell C., Hunt, William E., Hoke, Mark R., Bots, Henk J., Arrow, Leslie J.
• Primary Examiner(s): Beausoliel, Jr., Robert W.
• Assistant Examiner(s): ZIEMER, RITA A
• Application Number:
  US09/065,899
• Time in Patent Office: 999 Days
• Field of Search: 713/1, 713/100, 713/2
• US Class Current: 713/1
• CPC Class Codes: G06F 11/1417 Boot up procedures
• CPC Class Codes: G06F 9/441 Multiboot arrangements, i.e. selecting an operating system to be loaded

Abstract

One embodiment of the present invention provides a computer system with a plurality of storage memories, each storage memory storing an operating system program, and an identifier for identifying a storage memory containing an operating system program to be loaded when the unit is booted. The identifier is selectively switchable between storage memories so that the computer system may be selectively booted with an alternate operating system program. This facilitates loading a new version of an operating system, and then rapidly switching back to an old version of the operating system if the new version fails to function properly.

Claims

1. A method of configuring a computer system having a plurality of storage areas, comprising:

receiving a configuration request;

retrieving a pointer to a first storage area having resident therein a first operating system program;

receiving a second operating system program;

storing the second operating system program in a second storage area; and

automatically modifying the pointer to point to the second storage area in response to the storage of the second operating system;

wherein the pointer identifies, before the system is rebooted, one of the plurality of storage areas containing an operating system program to be loaded when the computer system is rebooted.

2. The method of claim 1, further comprising:

receiving a request to reboot the computer system;

rebooting the computer system;

retrieving the pointer; and

loading the second operating system program from the second storage area.

3. The method of claim 2, further comprising:

running the second operating system;

if the second operating system fails, modifying the pointer to point to the first storage area; and

loading the first operating system program from the first storage area.

4. The method of claim 2, further comprising:

incrementing a counter when the computer system is rebooted; and

modifying the pointer to identify the first storage area if a pre-specified number of reboot operations is detected in a pre-determined period of time.

5. The method of claim 2, wherein the request to reboot the computer system is received from a remote manager.

6. The method of claim 1, wherein receiving the second operating system program comprises:

accepting a stream of binary data through a communication port of the computer system;

storing the binary data stream in a third storage area; and

verifying the integrity of the binary data stream.

7. The method of claim 1, wherein the plurality of storage areas includes a first flash memory.

8. The method of claim 7, wherein the plurality of storage areas further includes a second flash memory.

9. The method of claim 1, wherein the configuration request is received from a manager coupled to the computer system via a communication link.

10. The method of claim 1, wherein storing the second operating system program comprises overwriting a third operating system program stored in the second storage area.

11. The method of claim 1, wherein the computer system is part of a virtual private network unit for passing secure communications between members of a virtual private network.

12. The method of claim 11, wherein the configuration request and request to reboot the computer system are received from a virtual private network manager.

13. The method of claim 12, further comprising authenticating the virtual private network manager.

14. An apparatus comprising:

a first storage area for storing a first operating system program;

a second storage area for storing a second operating system program;

an identification mechanism for selectively identifying one of the first storage area or the second storage area, the identification mechanism identifying the first storage area in a first state;

a processor for executing an operating system program resident in one of the first storage area or second storage area; and

a communication port;

wherein the identification mechanism is automatically modified in a second state to identify the second storage area in response to receiving the second operating system through the communication port.

15. The apparatus of claim 14, wherein the identification mechanism identifies, before the apparatus reboots, the storage area from which an operating system program will be loaded when the apparatus reboots.

16. The apparatus of claim 14, wherein the second operating system program received through the communication port is stored in the second storage area.

17. The apparatus of claim 16, further comprising a counter for counting the number of times the apparatus reboots after the second operating system program is stored in the second storage area.

18. The apparatus of claim 17, wherein the identification mechanism is modified in a third state to identify the first storage area if the counter is increased to a pre-determined number within a pre-specified period of time.

19. The apparatus of claim 14, wherein the identification mechanism is modified in a third state to identify the first storage area.

20. The apparatus of claim 19, wherein in the third state the identification mechanism is automatically modified to identify the first storage area in response to a command received through the communication port from an external computer system.

21. The apparatus of claim 14, wherein the identification mechanism is configured to identify the first storage area so that the first operating system program will be loaded, after a failure of the second operating system program is detected.

22. The apparatus of claim 14, wherein the first storage area is a flash memory.

23. The apparatus of claim 22, wherein the second storage area is a flash memory.

24. The apparatus of claim 14, wherein a command to reboot is received through the communication port, in response to which the apparatus reboots and loads an operating system program from the storage area identified by the identification mechanism.

25. The apparatus of claim 14, wherein the apparatus is part of a virtual private network unit providing a method of exchanging secure communications between a first computer system and a second computer system.

26. A method of operating a computer system having a processor, comprising:

storing a first operating system program in a first storage area;

storing a second operating system program in a second storage area;

storing a pointer to the first storage area;

executing instructions according to the first operating system program;

automatically replacing the pointer to the first storage area with a pointer to the second storage area in response to the storage of the second operating system program;

rebooting the computer system; and

executing instructions according to the second operating system program.

27. The method of claim 26, further comprising:

receiving a third operating system program comprising a data stream;

verifying the integrity of the data stream;

storing the third operating system program in the first storage area, thereby replacing the first operating system program;

replacing the pointer to the second storage area with a pointer to the first storage area; and

rebooting the computer system.

28. The method of claim 27, further comprising:

initializing a counter;

incrementing the counter each time the computer system reboots; and

replacing the pointer to the first storage area with a pointer to the second storage area if the counter is incremented to a pre-specified value in a pre-determined period of time.

29. The method of claim 26, further comprising replacing the pointer to the second storage area with a pointer to the first storage area.

30. The method of claim 29, further comprising:

rebooting the computer system; and

executing instructions according to the first operating system program.

31. The method of claim 26, wherein the computer system is part of a virtual private network unit for passing secure communications between members of a virtual private network.

32. The method of claim 31, further comprising:

receiving a data packet from a first member of the virtual private network;

transforming the data packet; and

transmitting the transformed data packet to a second member of the virtual private network.

33. The method of claim 32, wherein the transforming step comprises encrypting the data packet.

34. The method of claim 32, wherein the transforming step comprises decrypting the data packet.

35. An apparatus for processing data communications, comprising:

a first nonvolatile storage area for storing a first sequence of operating instructions;

a second nonvolatile storage area for storing a second sequence of operating instructions;

an identifier for identifying one of the first storage area or the second storage area, the identifier being selectively switchable;

a processor for executing the sequence of operating instructions stored in the storage area identified by the identifier; and

a communication port electrically coupled to a manager;

wherein the identifier is automatically switched from identifying the first storage area in a first state, to identifying the second storage in a second state, in response to a command received from the manager through the communication port.

36. The method of claim 35, wherein the command comprises a third sequence of operating instructions that is stored in the second storage area.

37. The method of claim 36, wherein the apparatus reboots after storing the third sequence of operating instructions and the processor executes according to the third sequence of operating instructions.

38. A method of configuring a computer system, comprising:

receiving a request to replace a first operating system program stored on the computer system with a second operating system program;

retrieving the second operating system program;

examining a single pointer configured to identify, among a plurality of operating system program storage areas, a first storage area in which the first operating system program is stored;

transmitting the second operating system program to the computer system;

receiving verification that the second operating system program has replaced the first operating system program;

automatically changing the single pointer to identify, among the plurality of operating system program storage areas, a second storage area in which the second operating system program is stored; and

rebooting the computer system.

39. The method of claim 38, wherein the rebooting step comprises automatically determining, by examining only the single pointer, from which of the plurality of operating system storage areas an operating system program is to be loaded.