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Software reliability refers to the probability of failure-free operation of a system. It is related to many aspects of software, including the testing process. Directly estimating software reliability by quantifying its related factors can be difficult. Testing is an effective sampling method to measure software reliability. Guided by the operational profile, software testing (usually black-box testing) can be used to obtain failure data, and an estimation model can be further used to analyze the data to estimate the present reliability and predict future reliability. Therefore, based on the estimation, the developers can decide whether to release the software, and the users can decide whether to adopt and use the software. Risk of using software can also be assessed based on reliability information. The primary goal of testing should be to measure the dependability of tested software.

There is agreement on the intuitive meaning of dependable software: it does not fail in unexpected or catastrophic ways. Robustness testing and stress testing are variances of reliability testing based on this simple criterion.

The robustness of a software component is the degree to which it can function correctly in the presence of exceptional inputs or stressful environmental conditions. Robustness testing differs with correctness testing in the sense that the functional correctness of the software is not of concern. It only watches for robustness problems such as machine crashes, process hangs or abnormal termination. The oracle is relatively simple, therefore robustness testing can be made more portable and scalable than correctness testing. This research has drawn more and more interests recently, most of which uses commercial operating systems as their target.

Stress testing, or load testing, is often used to test the whole system rather than the software alone. In such tests the software or system are exercised with or beyond the specified limits. Typical stress includes resource exhaustion, bursts of activities, and sustained high loads.

Regression testing

According to (IEEE610.12-90), regression testing is the “selective retesting of a system or component to verify that modifications have not caused unintended effects...” In practice, the idea is to show that software which previously passed the tests still does. Beizer defines it as any repetition of tests intended to show that the software’s behavior is unchanged, except insofar as required. Obviously a trade-off must be made between the assurance given by regression testing every time a change is made and the resources required to do that.

Regression testing can be conducted at each of the test levels. The target of the test and may apply to functional and nonfunctional testing.

Correctness testing

Correctness is the minimum requirement of software, the essential purpose of testing. Correctness testing will need some type of oracle, to tell the right behavior from the wrong one. The tester may or may not know the inside details of the software module under test, e.g. control flow, data flow, etc. Therefore, either a white-box point of view or black-box point of view can be taken in testing software. We must note that the black-box and white-box ideas are not limited in correctness testing only.

Questions & Answers

give me coding of these projects
Aman Reply
feasibility study&fact gathering techniques
Nachi Reply
write about software engineering
Mandala Reply
8.10.0.
BARBU
define iterative model. example of iterative model. advantages and disadvantages of iterative model. when to use iterative model
Okello Reply
i try out in netbeans this code:public class Profile { private Profile(int w) { // line 1 System.out.println(w); } public final Profile() { // line 5 System.out.println(10); } public static void main(String args[]) { Profile obj = new Profile(50); } } It is the question 5, and the answer is 50
Jacqueline Reply
how to join conversation
Bablu
i need help....Discuss the factors that influence the choice of the software development methodology to use when implementing software projects?(20)
tatenda Reply
The success rate of software development projects can be increased by using a methodology that is adequate for the specific characteristics of those projects.  then the focus on RAD,XP,RUP.
Hemant
hemant hie...it is a presentation i am working on...can you help me wth the introduction....please a powerful one hahahahha
tatenda
yes
Hemant
Define and show all Dipthongs and vowels used in english phonetics
Okendro Reply
what is the software engineering
Axmed Reply
please
Jennifer
hhahhaha
martin
software engineering is a organized process of activities for development a use full software . it may consist of : 1:spcecification 2:design 3: implementation 4: evolution:
hamayun
Please how can I create an application?
Eric Reply
please how can I create an application
Nchor
How do we create a software
Florence Reply
give a more direct question
Louis Reply
what is semantics?
amjad
what r the computer codes
Kawuba Reply
machine code, source code , object code, and byte code etc
Hemant
what is software
Manobendra Reply
a collection of program executable by code is called software
Hemant
how can I create a software
Mary Reply
use in any model . then after you create any software
Hemant
what is capability maturity model integration
Muctarr
what is maturity level
Muctarr
maturity level is organization's process improvement achievement in multiple process areas
Hemant
how to trubulshoot is configuration ?
priya Reply
hello
Julius
hello
abeer
hello
Sahil
hello
Natnael
Hello
Eric
Guy's put your answer only
Natnael
click start then click run then type msconfig then ok
Natnael

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Source:  OpenStax, Software engineering. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10790/1.1
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