Fault resilient/fault tolerant computing

• US 6,205,565 B1
• Filed: 05/19/1998
• Issued: 03/20/2001
• Est. Priority Date: 09/17/1996
• Status: Expired due to Term

• Current Assignee: Stratus Technologies Bermuda Ltd. (Stratus Technologies Bermuda Holdings Ltd.)
• Original Assignee: Marathon Technologies Corporation (Stratus Technologies Bermuda Holdings Ltd.)
• Inventors: Fitzgerald, V, Martin J., Leveille, Paul A., McCollum, James D., Muench, Erik, Tremblay, Glenn A., Bissett, Thomas D.
• Primary Examiner(s): Iqbal, Nadeem
• Application Number:
  US09/081,074
• Time in Patent Office: 1,036 Days
• Field of Search: 714/49, 714/1, 714/2, 714/6, 714/7, 714/8, 714/10, 714/11-13, 714/16, 714/20, 714/25, 714/31, 714/47, 714/48, 714/5, 714/26, 714/40, 395/575, 395/725, 395/650, 364/184-187
• US Class Current: 714/49
• CPC Class Codes: G06F 11/07 Responding to the occurrence of a fault, e.g. fault tolerance
• CPC Class Codes: G06F 11/0709 in a distributed system consisting of a plurality of standalone computer nodes, e.g. clusters, client-server systems
• CPC Class Codes: G06F 11/0745 in an input/output transactions management context input/output processing in general G06F13/00
• CPC Class Codes: G06F 11/079 Root cause analysis, i.e. error or fault diagnosis in a hardware test environment G06F11/22; in a software test environment G06F11/36
• CPC Class Codes: G06F 11/1641 where the comparison is not performed by the redundant processing components
• CPC Class Codes: G06F 11/1645 and the comparison itself uses redundant hardware
• CPC Class Codes: G06F 11/165 with continued operation after detection of the error
• CPC Class Codes: G06F 11/1658 Data re-synchronization of a redundant component, or initial sync of replacement, additional or spare unit
• CPC Class Codes: G06F 11/1683 at instruction level
• CPC Class Codes: G06F 11/1691 using a quantum
• CPC Class Codes: G06F 11/20 using active fault-masking, e.g. by switching out faulty elements or by switching in spare elements
• CPC Class Codes: G06F 11/3065 Monitoring arrangements determined by the means or processing involved in reporting the monitored data error or fault reporting or logging G06F11/0766
• CPC Class Codes: G06F 11/327 Alarm or error message display
• CPC Class Codes: G06F 2201/845 Systems in which the redundancy can be transformed in increased performance

Abstract

Data transfer to computing elements is synchronized in a computer system that includes the computing elements and controllers that provide data from data sources to the computing elements. A request for data made by a computing element is intercepted and transmitted to the controllers. At least a first controller responds by transmitting requested data to the computing element and by indicating how a second controller will respond to the intercepted request.

Claims

1. A method of handling faults in a computer system, the computer system including computing elements, controllers that provide data from data sources to the computing elements, error reporting elements and error processing elements, the method comprising:

intercepting a request for data by a computing element;

transmitting the intercepted request to the controllers;

having at least one of the controllers respond by transmitting the requested data to the computing element;

detecting, through an error reporting element that comprises a computing element or a controller, an error condition and transmitting information about the error condition as an error message to error processing elements connected to the error reporting element, the error processing elements including at least two of the controllers, and

retransmitting the error message, through at least one error processing element, to other error processing elements connected to the at least one error processing element.

2. A method of handling faults in a computer system, the computer system including computing elements, controllers that provide data from data sources to the computing elements, error reporting elements and error processing elements, the method comprising:

intercepting a request for data by a computing element;

transmitting the intercepted request to the controllers;

having at least one of the controllers respond by transmitting the requested data to the computing element;

detecting, through error reporting elements that comprise the computing elements or the controllers, an error condition and transmitting information about the error condition as error messages to error processing elements connected to the error reporting elements, the error processing elements including at least two of the controllers, and

combining, through at least one error processing element, information from related error messages from multiple error reporting elements and using the combined information in identifying a source of the error condition.

3. The method of claim 2, wherein the at least one error processing element uses a state table to combine information from related error messages.

4. The method of claim 3, wherein the at least one error processing element represents an error message using an error identifier that identifies a particular error, an error target that identifies a subcomponent that caused the error represented by the error message, and a reporting source that identifies an error reporting element that generated the error message and a path over which the error message was received.

5. The method of claim 3, wherein the error processing element determines whether error messages are related by comparing a received error message against states representing previously received error messages.

8. The method of claim 2, further comprising retransmitting the error message, through at least one other error processing element, to other error processing elements connected to the at least one other error processing element.

9. The method of claim 2, further comprising determining that an error is associated with a particular error reporting element and a path between the particular error reporting element and the at least one error processing element when the at least one error processing element does not receive an expected error message from the particular error reporting element.

10. The method of claim 2, further comprising the at least one error processing element probing other system components to obtain error information.

11. The method of claim 2, further comprising the at least one error processing element grouping errors into sets of co-related errors.

12. The method of claim 11, wherein a set of co-related errors indicates a faulty component or a suspected list of faulty components with more specificity than any individual error is able to provide.

6. A computer system including:

computing elements,

controllers that provide data from data sources to the computing elements,

error reporting elements that include the computing elements, and

error processing elements that include at least two of the controllers, wherein;

an error reporting element is configured to detect an error condition and transmit information about the error condition as an error message to error processing elements connected to the error reporting element, and

at least one error processing element is configured to retransmit the error message to the other error processing elements connected to the at least one error processing element.

16. The system of claim 6, wherein the at least one error processing element is configured to retransmit the error message to other error processing elements connected to the at least one error processing element.

17. The system of claim 6, wherein the at least one error processing element is configured to determine that an error is associated with a particular error reporting element and a path between the particular error reporting element and the at least one error processing element when the at least one error processing element does not receive an expected error message from the particular error reporting element.

18. The system of claim 6, wherein the at least one error processing element is configured to probe other system components to obtain error information.

19. The system of claim 6, wherein the at least one error processing element is configured to group errors into sets of co-related errors.

20. The system of claim 19, wherein a set of co-related errors indicates a faulty component or a suspected list of faulty components with more specificity than any individual error is able to provide.

7. A computer system including:

computing elements,

controllers that provide data from data sources to the computing elements,

error reporting elements that include the computing elements or the controllers, and

error processing elements that include at least two of the controllers, wherein;

error reporting elements are configured to detect an error condition as error messages to error processing elements connected to the error reporting elements, and

at least one error processing element is configured to combine information from related error messages from multiple error reporting elements and use the combined information in identifying a source of the error condition.

13. The system of claim 7, wherein the at least one error processing element is configured to use a state table to combine information from related error messages.

14. The system of claim 13, wherein the at least one error processing element is configured to represent an error message using an error identifier that identifies a particular error, an error target that identifies a subcomponent that caused the error represented by the error message, and a reporting source that identifies an error reporting element that generated the error message and a path over which the error message was received.

15. The system of claim 13, wherein the error processing element is configured to determine whether error messages are related by comparing a received error message against states representing previously received error messages.