software quality assurance 常见问题收录
1. What is Quality?
Quality means,
“meeting requirements.”
..Whether or not the product or service does what the customer needs. In another word Quality is,
“fit for use.”
2. Explain “Prevention” & “Detection”.
..Prevention means to prevent quality defects or deficiencies in the first place, and to make the products and processes assessable by quality management program.
..Prevention decreases production costs because the sooner a defect is located and corrected, the less costly it will be in the long run.
..The greatest payback is with prevention.
3. Explain “Verification” & “Validation”
The overall goal of verification is to ensure that each software product developed throughout the software life cycle meets the customer’s needs and objectives as specified in the software requirements document.
Validation checks that the system meets the customer’s requirements at the end of the life cycle.
Usually Verifications take place at the end of each phase. Validations take place just before the product is delivered.
4. Cost of Quality includes:
Prevention cost
Appraisal cost （鉴定费用）
Internal failure cost
External failure cost
5. Explain “Prevention Cost”.
Prevention costs consist of actions taken to prevent defects from occurring the first place.
-quality planning
-formal technical reviews
-test equipment
- training
6. Explain “Appraisal (鉴定)Cost”.
Appraisal costs consist of measuring, evaluating, and auditing(审计) products or services for conformance (顺应)to standards and specifications.
-Inspection and testing of products
-Equipment calibration (校准) and maintenance
-Processing and reporting inspection data
7. What are the components of software quality assurance?
Most software quality assurance activities can be categorized into:
testing
quality control
software configuration management
The success software quality assurance program also depends on a coherent collection of standards, practices, conventions（习惯）, and specification（规格说明书）.
8. What are the elements of software configuration management?
1. Component Identification元件识别
In order to manage the development process, one must establish methods and name standards for uniquely identifying each revision.
2. Version Control版本控制
Version control provides the traceability of history of each software change, including who did what , why, and when.
3. Configuration Building配置构建
To build a software configuration one needs to identify the correct component versions and execute the component build procedures. This is often called configuration building.
4. Change Control变更控制
9. Why Change control is the key role in the Software Configuration Management?
SCM answers Who, What, When, and Why
• Who made the changes?
• What changes were made to the software?
• When were the changes made?
• Why were the changes made?
When a software component is changed, it should always be reviewed and frozen from further modifications until a new version is created.
10. What are the main responsibilities of SQA group?
1. The SQA group works with the software project during its early stages to establish plans, standards, and procedures that will add value to the software project and satisfy the project constraints and the organization’s policies.
2. The SQA group reviews project tasks and audits software work products throughout the SDLC life cycle and provides management with visibility as to whether the software project is adhering to its established objectives and standards.
1。SQA组的工作，在其早期阶段的软件项目制定计划，标准和程序，将添加到软件项目的价值，并满足项目约束和组织的政策。
2。 SQA组评论项目任务和审计软件工作产品整在个SDLC的生命周期，并提供管理软件项目是否遵守其既定的目标和标准的可视性。
11. Why do Dev people think that SQA groups are Spies to management?
The SQA group periodically(定期的) reports the results of its activities to the software engineering group.
Deviations(偏差) identified in the software activities and software work products are documented and handled according to a documented procedure.在软件活动和软件工作产品中识别的偏差都记录并书面程序处理。
Viewed as not having enough technical background, know nothing about the mechanics of building software.
Blame developers for poor quality but provide no solution
Insensitive to intelligent and talented developers and system engineers
12. What is CMMI?
Capability Maturity Model Integration
The Capability Maturity Model describes the principles and practices underlying software process maturity and is intended to help software organizations improve the maturity of their software process.
13. What is ISO?
ISO is the International Standard Organization .
It is located in Switzerland and was established in 1947 to develop common international standards in many areas. Its members come from over 120 national standards bodies . 它位于瑞士，成立于1947年，在许多领域制定共同的国际标准。它的成员来自超过120个国家标准机构。
These new standards are referred to as the "ISO 9000 2000 Standards".
14. What is PDCA?
Deming’s quality cycle
In the Plan Quadrant of the circle, objectives are defined and the conditions and methods required to achieve those objectives are determined.
In the Do quadrant of the circle, the conditions are created, training is performed. The work is performed according to plan.
In the Check quadrant of the circle, one must check to determine whether work is progressing according to the plan and whether the expected results are obtained.
In the Act quadrant of the circle, if the checkup reveals (显示) that the work is not being performed according to plan or that results are not what was anticipated (予期的), measures (措施) must be devised (作出) for appropriate action.
在该Plan中的圆的象限，目标被定义和实现这些目标所需要的条件和方法被确定。
在圆DO象限，条件被创造，培训执行。工作按计划进行。
在检查的圆的象限中，一个人必须检查，以确定是否工作正按照计划，是否得到预期的结果。
在Act象限的圆，如果在检查揭示（显示），工作没有按计划被执行或结果是没有达到预期，为适当动作措施必须被作出。
15. What is 80/20 rule? Give an example in Software Engineering field.
The Pareto principle states that, for many events, roughly 80% of the effects come from 20% of the causes. 帕累托原则规定，对于许多事件的影响，大约有80％来自20％的原因
Example: �20% of the modules consume 80% of the resources
�20% of the modules contribute 80% of the error
�20% of the errors consume 80% of repair costs
16. Explain the statistical software quality assurance by using your own words.
1. Information about software defects is collected and categorized.
2. An tempt is made to trace each defects to its underlying cause.
3. Using the Pareto principle (80/20 rule), isolate the 20 percent.
–80% of defects can be traced to 20% of all possible cause
4. Once the vital few causes have been identified, move to correct the problems that have caused the defects.
Concentrate on the vital few, not the trivial many.
17. What are the Limitations with Execution-Based Testing?
By the time testing occurs, it is too late to build quality into the product.
Tests are only as good
补充：综合编程 , 其他综合 ,
