Author: misamaliraza94
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Software Maintenance
Software maintenance is a part of the Software Development Life Cycle. Its primary goal is to modify and update software application after delivery to correct errors and to improve performance. Software is a model of the real world. When the real world changes, the software require alteration wherever possible. Software Maintenance is an inclusive activity…
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Musa-Okumoto Logarithmic Model
The failure intensity is: Belongs to the mean value function This is the functional form of the Musa-Okumoto logarithmic model: Like Musa’s basic execution time model, the “Logarithmic Poisson Execution Time Model” by Musa and Okumoto is based on failure data measured in execution time. Assumptions As the derivation of the Musa-Okumoto logarithmic model by…
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Goel-Okumoto (GO) Model
The model developed by Goel and Okumoto in 1979 is based on the following assumptions: Since each fault is perfectly repaired after it has caused a failure, the number of inherent faults in the software at the starting of testing is equal to the number of failures that will have appeared after an infinite amount…
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Basic Execution Time Model
This model was established by J.D. Musa in 1979, and it is based on execution time. The basic execution model is the most popular and generally used reliability growth model, mainly because: The basic execution model determines failure behavior initially using execution time. Execution time may later be converted in calendar time. The failure behavior…
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Jelinski and Moranda Model
The Jelinski-Moranda (JM) model, which is also a Markov process model, has strongly affected many later models which are in fact modifications of this simple model. Characteristics of JM Model Following are the characteristics of JM-Model: λ(ti) = ϕ [N-(i-1)], i=1, 2… N ………equation 1 Where ϕ=a constant of proportionality indicating the…
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Software Reliability Models
A software reliability model indicates the form of a random process that defines the behavior of software failures to time. Software reliability models have appeared as people try to understand the features of how and why software fails, and attempt to quantify software reliability. Over 200 models have been established since the early 1970s, but…
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Software Fault Tolerance
Software fault tolerance is the ability for software to detect and recover from a fault that is happening or has already happened in either the software or hardware in the system in which the software is running to provide service by the specification. Software fault tolerance is a necessary component to construct the next generation…
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Reliability Metrics
Reliability metrics are used to quantitatively expressed the reliability of the software product. The option of which metric is to be used depends upon the type of system to which it applies & the requirements of the application domain. Some reliability metrics which can be used to quantify the reliability of the software product are…
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Software Reliability Measurement Techniques
Reliability metrics are used to quantitatively expressed the reliability of the software product. The option of which parameter is to be used depends upon the type of system to which it applies & the requirements of the application domain. Measuring software reliability is a severe problem because we don’t have a good understanding of the nature…
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Software Failure Mechanisms
The software failure can be classified as: Transient failure: These failures only occur with specific inputs. Permanent failure: This failure appears on all inputs. Recoverable failure: System can recover without operator help. Unrecoverable failure: System can recover with operator help only. Non-corruption failure: Failure does not corrupt system state or data. Corrupting failure: It damages the system state or data. Software…