软件非功能性需求及案例

尔等的帅爹

ISO IEC IEEE 24765-2010_Systems and Software Engineering-Vocabulary defines:
a nonfunctional software requirement that describes not what the software will do but how the software will do it.  ISO IEC IEEE 24765- 2010_系统与软件工程词汇定义: 非功能性软件需求，它描述的不是软件将做什么，而是软件将如何做。
EXAMPLE software performance requirements, software external interface requirements, software design constraints, and software quality attributes. 例如软件性能需求、软件外部接口需求、软件设计约束和软件质量属性。
软件性能需求

ISO/IEC/IEEE24765:2010的标准中关于Performance（性能）的定义如下：
Performance : the degree to which a system or component accomplishes its designated functions within given constraints, such as speed, accuracy, or memory usage
性能：系统或组件在给定的限制条件（如速度、精度或内存使用）内完成其指定功能的程度。
Eg: Positioning accuracy error is not more than 30 meters, and the calculation is accurate to 2 decimal places. 定位精度误差不超过30⽶, 并且计算的精确性到⼩数点后2位。
Eg: After HU paired with Bluetooth device, when Bluetooth device in detecting range, the initial time should less than 5s to be ready to play media from Bluetooth device.HU与蓝牙设备配对后，当蓝牙设备在检测范围内时，初始时间应小于5s即可从蓝牙设备播放媒体。
Eg: Software shall provide mechanism to check the size of program memory space occupied by Basic Software and Application software and calibration.软件应提供检查基础软件和应用软件占用的程序内存空间大小和校准的机制。
软件外部接口需求

a system or software requirement that specifies a hardware, software, or database element with which a system/software system or system/software component must interface, or that sets forth constraints on formats, timing, or other factors caused by such an interface。
一种系统或软件要求，其中规定了系统/软件系统或系统/软件组件必须与之接口的硬件、软件或数据库元素，以及由该接口引起的格式、时间或其它因素的限制。
Eg:Temperature and/or Temperature Range (from a temperature sensor).温度和/或温度范围(来自温度传感器)
Eg:Electrical constrains (e.g. voltage range, maximal output current, PWM frequency and range of duty cycle, CAN baud rate).电气约束(例如电压范围，最大输出电流，PWM频率和占空比范围，CAN波特率)
Eg: inter-process communication mechanisms or bus communication mechanisms, message fields and allowed scope(max, min value), time related behavior.进程间通信机制或总线通信机制、消息字段和允许的范围(最大值、最小值)、与时间相关的行为
软件设计约束

The limitations on software design and implementation mainly refer to the limitations on software designers. Such as software operating environment restrictions (use of configuration, operating system restrictions, etc.), design tools restrictions (use of language, implementation standards) and confidentiality requirements.
软件设计和实现上的限制主要指对软件设计者的限制。如软件运行环境的限制（使用配置，操作系统的限制等）、设计工具的限制（使用语言、执行的标准）和保密要求等。
Eg: software logic design of external light should meet Industry standards and Government laws and regulations.外灯的软件逻辑设计要满足Industry（行业）规范和Government（政府）的法律法规
Eg: The basic software shall be configured with the AUTOSAR XML files provided by OEM in the format AUTOSAR Release 4.3. 基本软件应配置OEM提供的AUTOSAR XML文件，格式为AUTOSAR Release 4.3。
Eg: The following MISRA regulations shall be complied with: MISRA C:2012 for C-code, MISRA C++:2008 for C++-code. C-code应遵守MISRA C:2012, c++ -code应遵守MISRA c++:2008。
软件质量属性

文献中最常用的质量标准解释如下：


总结

⾮功能性需求是需求的⼀个重要组成部分，它影响了系统的架构设计，需要开发⼈员重点关注。但是在⼯程实践中，往往客户不会提出⾮功能性需求，需求⼈员在描述需求时不知道如何描述，在国际的各种标准中，对⾮功能性需求有定义，但是⽐较抽象。
以上是我对常见几类非功能性需求的小小总结仅供大家参考，当然在实际应用中还需结合技术、环境等因素以确保非功能性需求的覆盖率和执行度。