Automated system testability assessment method
First Claim
1. A process for automatically determining at least one of testability and maintainability parameters of a system composed of modules, comprising the steps of:
- (a) inputting failure rate data specifying a failure rate for at least one failure mode of at least one module, detected by each test path performable during testing of the system;
(b) automatically ordering the modules for each of the failure modes detected by each test path in descending order of the failure rate corresponding thereto; and
(c) identifying, for each test path, an order for iterative repair of the modules for each of the failure modes detected by the test path, in dependence upon said ordering in step (b).
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Accused Products
Abstract
A procedure for calculating maintainability and testability parameters of a complex system uses computer software to enable the calculations to be made repeatedly during the development of the system. Failure modes and failure rates, elemental task times and test path data from a branching test flow diagram are input. Screens which identify the data to be input are displayed for ease of data entry. A hierarchical relationship between the modules in the system can be entered so that failure modes and failure rates need only be entered for lowest level modules. The procedure iteratively calculates maintainability and testability parameters starting at the lowest level and using previously calculated data in the next highest level. Fault isolation ambiguity is automatically taken into account by ordering the modules in descending order of total test path/module failure rate isolated by each test path. The ordered data are used in many of the calculations of the maintainability and testability parameters.
98 Citations
19 Claims
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1. A process for automatically determining at least one of testability and maintainability parameters of a system composed of modules, comprising the steps of:
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(a) inputting failure rate data specifying a failure rate for at least one failure mode of at least one module, detected by each test path performable during testing of the system; (b) automatically ordering the modules for each of the failure modes detected by each test path in descending order of the failure rate corresponding thereto; and (c) identifying, for each test path, an order for iterative repair of the modules for each of the failure modes detected by the test path, in dependence upon said ordering in step (b). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A process for automatically determining at least one of testability and maintainability parameters of a system composed of modules testable using a plurality of methods of fault detection and isolation, comprising the steps of:
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(a) displaying an input screen for at least one module to provide fields for input of failure mode, failure rate, percent failure contribution, method of fault detection/isolation and test path identifier; (b) inputting failure data for all of the failure modes of the at least one module using the input screen displayed in step (a); (c) calculating a percentage of fault isolation of the system accomplishable using each of the methods and requiring replacement of n modules, said calculating being performed for n equal to each integer from one up to a predetermined number. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A process for automatically determining testability and maintainability parameters of a system composed of modules testable using a plurality of methods of fault detection and isolation, comprising the steps of:
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(a) producing a test flow diagram having branching nodes representing diagnostic tests not requiring reassembly and termination nodes represented by a test path identifier, each corresponding to a unique test path through the test flow diagram; (b) inputting test path data identifying all of the methods of fault detection and isolation used in the unique test path corresponding to each test path identifier; (c) inputting module relationship data defining a hierarchical relationship between the modules, including highest and lowest levels of the hierarchical relationship, the hierarchical relationship corresponding to organization of maintenance for the system; (d) displaying input screens for each of the modules in the lowest level of the hierarchical relationship, each input screen providing fields for input of a failure mode, a failure rate, percent failure contribution, at least one method of fault detection/isolation and a test path identifier; (e) inputting failure data corresponding to all of the failure modes of each of the modules in the lowest level of the hierarchical relationship, using the input screens displayed in step (a); (f) inputting maintenance task data specifying elemental task times of steps and procedures performed when each of the test paths is completed; (g) calculating a total test path/module failure rate corresponding to all of the failure modes, isolated by each of the test paths; (h) automatically ordering the modules corresponding to the failure modes detected by each of the test paths in descending order of the total test path/module failure rate calculated in step (f); (i) outputting, for each test path, an order for repair of the modules having the failure mode detected by the test path, in dependence upon said ordering in step (g); (j) calculating testability parameters including percentage of successful fault isolations requiring only n module replacements in dependence upon said ordering in step (g), said calculating being performed for n equal to each integer from one up to a predetermined number; (k) automatically producing time lines of maintenance procedures to be performed in response to traversing each of the test paths, using the maintenance task data input in step (f), with multiple time lines produced for each of the test paths isolating a plurality of modules, the plurality of time lines incrementally adding modules according to said ordering in step (g); (l) calculating maintainability parameters in dependence upon said time lines produced in step (k); and (m) repeating steps (h)-(l) for at least one level of modules higher than the lowest level of modules in the hierarchical relationship.
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Specification