Methods and apparatus for diagnosing a degree of interference between a plurality of faults in a system under test

• US 20080104470A1
• Filed: 10/12/2006
• Published: 05/01/2008
• Est. Priority Date: 10/12/2006
• Status: Active Grant

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Benvenga, Carl E.
• Granted Patent: US 7,673,210 B2
• Time in Patent Office: Days
• US Class Current: 714/738
• CPC Class Codes: G01R 31/2846 using hard- or software simulation or using knowledge-based systems, e.g. expert systems, artificial intelligence or interactive algorithms
• CPC Class Codes: G06F 11/263 Generation of test inputs, e.g. test vectors, patterns or sequences ; with adaptation of the tested hardware for testability with external testers
• CPC Class Codes: G06F 11/273 Tester hardware, i.e. output processing circuits G06F11/263 takes precedence

Abstract

A method for diagnosing a degree of interference between a plurality of faults in a system under test, the faults being detected by means of applying a test suite to the system under test, includes: 1) for each of the plurality of faults, and for each of a plurality of test syndromes, where a test syndrome is a pattern of passing and failing tests of the test suite, determining relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes; and 2) using the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes to calculate and display to a user, via a graphical user interface, and for the test suite as a whole, test suite degrees of interference between pairs of the faults. Other embodiments are also disclosed.

Claims

1. A method for diagnosing a degree of interference between a plurality of faults in a system under test, the faults being detected by means of applying a test suite to the system under test, comprising:

for each of the plurality of faults, and for each of a plurality of test syndromes, where a test syndrome is a pattern of passing and failing tests of the test suite, determining relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes; and

using the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes to calculate and display to a user, via a graphical user interface, and for the test suite as a whole, test suite degrees of interference between pairs of the faults.

2. The method of claim 1, wherein determining the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes comprises generating a matrix of faults versus test syndromes, where the intersection of a particular fault and a particular syndrome provides the relative frequency at which the particular fault is coupled with the particular syndrome.

3. The method of claim 1, wherein determining the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes comprises performing a statistical simulation of executing the tests of the test suite on the components of the system under test.

4. The method of claim 1, wherein determining the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes comprises analyzing historical test data of executing the tests of the test suite on the components of the system under test.

5. The method of claim 1, further comprising:

modeling the system under test as one or more components, each of which may be associated with one or more faults;

modeling the test suite as a plurality of tests that pass or fail based on one or more of the components exhibiting their associated faults;

modeling each test as covering some portion of one or more of the faults, based on each test'"'"'s ability to detect one or more of the faults.

6. The method of claim 5, wherein the plurality of faults comprises at least one of:

component faults and multiple component faults.

7. The method of claim 1, wherein a particular test suite degree of interference (DOI_{Test Suite}) between a pair of faults F1 and F2 is calculated as:

DOI_{Test Suite}(F1,F2)=Σ

_{All S}[c[min(f_s,1,f_s,2)]]/Σ

_{All S}(f_s,1+f_s,2);

where S is a particular syndrome, c is a constant, f_s,1 is the relative frequency at which the fault F1 is coupled with the syndrome S, f_s,2 is the relative frequency at which the fault F2 is coupled with the syndrome S, and min(f_s,1, f_s,2) is a function that determines the minimum of f_s,1 and f_s,2.

8. The method of claim 7, wherein c=2.

9. The method of claim 1, further comprising:

displaying to the user, via the graphical user interface, a list of the faults; and

upon user selection of one of the faults (F1), and via the graphical user interface, i) displaying a list of faults that interfere with the fault F1, and ii) for each of the faults that interfere with the fault F1, displaying a corresponding one of the test suite degrees of interference between pairs of the faults.

10. The method of claim 9, further comprising:

displaying with each of the faults, in a common dialog of the graphical user interface, a relative frequency at which the fault appears for all syndromes in the test suite.

11. The method of claim 9, further comprising:

displaying with each of the faults, in a common dialog of the graphical user interface, a number of faults that interfere with each fault.

12. The method of claim 9, further comprising:

using the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes to calculate and display to a user, via a graphical user interface, and for particular syndromes, syndrome degrees of interference between pairs of the faults.

13. The method of claim 12, further comprising:

upon user selection of one of the faults (F2) that interferes with the fault F1, and via the graphical user interface, i) displaying a list of syndromes shared by the faults F1 and F2, and ii) displaying for each syndrome in the list of syndromes, a corresponding one of the syndrome degrees of interference between the faults F1 and F2.

14. The method of claim 13, further comprising:

for each of the syndromes shared by the faults F1 and F2, displaying to the user via the graphical user interface, a relative frequency at which the syndrome appears for all faults in the test suite.

15. The method of claim 14, further comprising:

for each of the syndromes shared by the faults F1 and F2, displaying to the user via the graphical user interface, the pattern of passing and failing tests that corresponds to the syndrome; and

displaying the list of syndromes, the corresponding ones of the syndrome degrees of interference between the faults F1 and F2, the relative frequencies at which each syndrome appears for all faults in the test suite, and the patterns of passing and failing tests that correspond to the syndromes, in a common dialog of the graphical user interface.

16. The method of claim 13, further comprising:

for each of the syndromes shared by the faults F1 and F2, displaying to the user via the graphical user interface, the pattern of passing and failing tests that corresponds to the syndrome.

17. The method of claim 1, further comprising:

using the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes to calculate and display to a user, via a graphical user interface, and for particular syndromes, syndrome degrees of interference between pairs of the faults.

18. A method for diagnosing a degree of interference between a plurality of faults in a system under test, the faults being detected by means of applying a test suite to the system under test, comprising:

for each of the plurality of faults, and for each of a plurality of test syndromes, where a test syndrome is a pattern of passing and failing tests of the test suite, determining relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes; and

using the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes to calculate and display to a user, via a graphical user interface, and for particular syndromes, syndrome degrees of interference between pairs of the faults.

19. The method of claim 18, wherein determining the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes comprises generating a matrix of faults versus test syndromes, where the intersection of a particular fault and a particular syndrome provides the relative frequency at which the particular fault is coupled with the particular syndrome.

20. The method of claim 18, wherein determining the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes comprises performing a statistical simulation of executing the tests of the test suite on the components of the system under test.

21. The method of claim 18, wherein determining the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes comprises analyzing historical test data of executing the tests of the test suite on the components of the system under test.

22. The method of claim 18, further comprising:

modeling the system under test as one or more components, each of which may be associated with one or more faults;

modeling the test suite as a plurality of tests that pass or fail based on one or more of the components exhibiting their associated faults;

modeling each test as covering some portion of one or more of the faults, based on each test'"'"'s ability to detect one or more of the faults.

23. The method of claim 22, wherein the plurality of faults comprises at least one of:

component faults and multiple component faults.

24. The method of claim 23, wherein a particular syndrome degree of interference (DOI_s) between a pair of faults F1 and F2 is calculated as:

DOI_s(F1,F2)=c[min(f_s,1,f_s,2)]/(f_s,1+f_s,2);

where S is a particular syndrome, c is a constant, f_s,1 is the relative frequency at which the fault F1 is coupled with the syndrome S, f_s,2 is the relative frequency at which the fault F2 is coupled with the syndrome S, and min(f_s,1, f_s,2) is a function that determines the minimum of f_s,1 and f_s,2.

25. The method of claim 24, wherein c=2.

26. The method of claim 23, further comprising:

displaying to the user, via the graphical user interface, i) a list of the syndromes shared by two interfering ones of the faults, and ii) for each of the syndromes shared by the two interfering ones of the faults, a corresponding one of the syndrome degrees of interference between the two interfering ones of the faults.

27. The method of claim 26, further comprising:

for each of the syndromes shared by the two interfering ones of the faults, displaying to the user via the graphical user interface, a relative frequency at which the syndrome appears for all faults in the test suite.

28. The method of claim 26, further comprising:

for each of the syndromes shared by the two interfering ones of the faults, displaying to the user via the graphical user interface, the pattern of passing and failing tests that corresponds to the syndrome.

29. Apparatus for diagnosing a degree of interference between a plurality of faults in a system under test, the faults being detected by means of applying a test suite to the system under test, comprising:

computer-readable media; and

computer-readable program code, stored on the computer-readable media, including;

code to, for each of the plurality of faults, and for each of a plurality of test syndromes, where a test syndrome is a pattern of passing and failing tests of the test suite, determine relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes; and

code to use the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes to calculate and display to a user, via a graphical user interface, and for the test suite as a whole, test suite degrees of interference between pairs of the faults.

30. The apparatus of claim 29, wherein the code to determine the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes comprises performs a statistical simulation of executing the tests of the test suite on the components of the system under test.

31. The apparatus of claim 29, wherein a particular test suite degree of interference (DOI_{Test Suite}) between a pair of faults F1 and F2 is calculated by the code as:

DOI_{Test Suite}(F1,F2)=Σ

_{All S}[c[min(f_s,1,f_s,2)]]/Σ

_{All S}(f_s,1+f_s,2);

where S is a particular syndrome, c is a constant, f_s,1 is the relative frequency at which the fault F1 is coupled with the syndrome S, f_s,2 is the relative frequency at which the fault F2 is coupled with the syndrome S, and min(f_s,1, f_s,2) is a function that determines the minimum of f_s,1 and f_s,2.

32. The apparatus of claim 29, further comprising:

code to display to the user, via the graphical user interface, a list of the faults; and

code to, upon user selection of one of the faults (F1), and via the graphical user interface, i) display a list of faults that interfere with the fault F1, and ii) for each of the faults that interfere with the fault F1, display a corresponding one of the test suite degrees of interference between pairs of the faults.

33. The apparatus of claim 29, further comprising:

code to use the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes to calculate and display to a user, via a graphical user interface, and for particular syndromes, syndrome degrees of interference between pairs of the faults.

34. Apparatus for diagnosing a degree of interference between a plurality of faults in a system under test, the faults being detected by means of applying a test suite to the system under test, comprising:

computer-readable media; and

computer-readable program code, stored on the computer-readable media, including;

code to, for each of the plurality of faults, and for each of a plurality of test syndromes, where a test syndrome is a pattern of passing and failing tests of the test suite, determine relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes; and

code to use the relative frequencies at which particular ones of the faults are coupled with particular ones of the syndromes to calculate and display to a user, via a graphical user interface, and for particular syndromes, syndrome degrees of interference between pairs of the faults.

35. The apparatus of claim 34, wherein a particular syndrome degree of interference (DOI_s) between a pair of faults F1 and F2 is calculated by the code as:

DOI_s(F1,F2)=c[min(f_s,1,f_s,2)]/(f_s,1+f_s,2);

where S is a particular syndrome, c is a constant, f_s,1 is the relative frequency at which the fault F1 is coupled with the syndrome S, and f_s,2 is the relative frequency at which the fault F2 is coupled with the syndrome S, and min(f_s,1, f_s,2) is a function that determines the minimum of f_s,1 and f_s,2.

36. The apparatus of claim 34, further comprising:

code to display to the user, via the graphical user interface, i) a list of the syndromes shared by two interfering ones of the faults, and ii) for each of the syndromes shared by the two interfering ones of the faults, a corresponding one of the syndrome degrees of interference between the two interfering ones of the faults.