Ch3 Flashcards
is meeting the basic requirements enough to make a successful software? why
No it is not enough, there are other important non-functional requirements that should be met, like maintenance and reliability, reuse and training.
how to avoid performance issues in any software?
- having good documentation
- having clear and planned requirements
what do you need to have a really good software quality?
to have a good software quality you need your software to meet the specified quality requirements, so you need a requirement document that clearly specifies the requirements to have a good quality software.
can a software fail because of a poor quality requirement document?
yes, the software can be functional, but can do poor performance if the requirements document quality is poor. (see the first 2 examples in the chapter)
What are some common software quality factors that projects frequently lack?
usability
reusability
maintainability
reliability
scalability
portability (work on all platforms and enviorments)
is it natural to assume or have inequality between different quality requirements?
yes, because the need of them differs from a project to another.
can we consider quality factors as non-functional requirements?
yes, because software quality can’t be achieved when meeting the functional requirements alone
What is the primary focus of software engineering
Capturing, designing, implementing, and deploying with emphasis on functional requirements
What is the emphasis on non-functional requirements (quality factors) in software engineering
1-There is little emphasis (but not none), though more importance is now being placed on quality factors.
Why are quality factors (non-functional requirements) important?
They can be a critical factor in satisfying overall requirements. and make the SQ high and work with high performance.
Where are non-functional requirements typically documented
In the Software Requirements Specification (SRS) document
Where are functional requirements usually captured
In Use Case Stories
What are Software Quality Factors, and where are they documented
Software Quality Factors define the non-functional aspects of software (e.g., usability, reliability, maintainability). They are included in the requirements document (SRS)
What are software quality factors
They are attributes that determine the quality of software, such as reliability, maintainability, and usability. (non-functional requirements)
Are there different models for software quality?
Yes, there are various models used to define and measure software quality
What is the classic software quality factor model?
The McCall software quality model
How many quality factors does McCall’s model have, and how are they grouped?
McCall’s model has 11 quality factors, grouped into 3 categories
what are the 3 categories the the McCall model group it’s quality factors in?
Product Operation
Product Revision
Product Transition
What is the Product Operation category in McCall’s model?
It includes factors that directly affect the daily operation of software:
Correctness
Reliability
Efficiency
Integrity
Usability
What does Product Revision refer to in McCall’s model?
It covers factors that affect software maintenance activities:
Maintainability
Flexibility
Testability
What does Product Transition focus on in McCall’s model?
It deals with software adaptability to the environment and interaction with other systems:
Portability
Reusability
Interoperability
What is Correctness in McCall’s Product Operation category?
It refers to whether the software performs the tasks it was designed for without errors (does the task correctly).
How to know the that the software has the correctness quality factor?
we check if it meets the dimensions of the output specifications ( شروط النتيجة المتوقعة من البرنامج)
What are some dimensions of output specifications in software correctness
Output mission (e.g., documents, alarms, voice)
Required accuracy
Completeness
Up-to-date information
Availability (reaction time)
Standards for coding and documentation
Explain each one of the output specification when talking about the software correctness
1.out put mission (what type of data to output? voice, image , document)
2-The required accuracy ( percentage of data that is not accurate)
3-Completness ( give a percentage of non-complete data)
4-Up-to-date information(specify a limit to how old the data should be )
5-Availability (reaction time of getting the information or document )
6-Standards for coding and documentation (software must go by the client’s or the required guidelines, for it to be well structured and do the required thing from it without any errors)
What is Reliability in McCall’s Product Operation category?
It refers to the ability of software to run without crashes or failures over time.
How is Reliability Measured?
1-Failure rate: Determines the acceptable number of failures over time.
2-Can apply to the entire system or specific functions.
What does reliability deal with in software?
It deals with failures to provide service and determines the maximum allowed system failure rate
How to determine the failure rate?
1-either by using years (so like once in 20 years)
2-by using numbers (1 fail every million use)
What is the purpose of software integrity?
To protect data from being accessed or modified by unauthorized users
What do integrity requirements deal with?
They deal with software system security to prevent unauthorized access.
What is the distinction made in integrity requirements?
It distinguishes between personnel with read permits (who can see data) and those with write permits (who can modify data).
Who are integrity requirements designed to prevent access from?
Unauthorized persons.
Who might determine the access limitations to the system data?
The systems head
What should software efficiency ensure?
The software should use computer resources (memory, CPU, battery) effectively.
What does efficiency deal with?
It deals with the hardware resources needed to perform all functions of the software system.
How should efficiency conform to other requirements?
The hardware resources should support all functions of the software system while maintaining conformance(التوافق ) with all other requirements.
What is Usability in McCall’s Product Operation category?
The software should be easy to use and understand.
What does usability deal with?
staff resources needed to train new employees and operate the software system.
What measures can be used in usability examples?
1-Training hours and what is expected from the user after that
2-How much should the normal user do or perform (ex: 60 calls a day)
What is maintainability in McCall’s Product revision category?
The software should be easy to fix if there are bugs or errors.
What do maintainability requirements determine?
the efforts users and maintenance personnel should do to:
1-Identify the reasons for software failures.
2-Correct the failure.
3-Verify the success of the corrections.
The better the maintainability the less the effort needed
What is a Software Module?
A software module is a self-contained and independent unit of code within a larger software system. It is designed to perform a specific function
Key Strategies to Improve Maintainability
1-Write Clean and Readable Code (use standards and guides)
2-Modularize the Code (Use a Modular Architecture, break code into smaller modules)
3-Use Version Control Systems (VCS)
4-Implement Automated Testing
What is a Version Control System (VCS)?
A tool that helps track code changes, revert to previous versions, and collaborate with teams.(Git and GitHub.)
What is flexibility in McCall’s Product revision category?
1-The ability of software to adapt to changes in user requirements and all possible environments and conditions.
2-The capabilities and efforts required to support adaptive maintenance activities.
3-Perfective maintenance in software?
Adaptive Maintenance Activities mean?
They are activities done to modify (maintained) the software to adapt with external changes.
What is perfective maintenance in software?
Enhancing the software by adding new features or improving existing ones to provide better service.
How to Improve Flexibility?
1-Modular Design – Break the software into independent modules.
2-Use APIs – Allow third-party services to integrate easily.
3-Configuration Files – Store adjustable settings in external files (e.g., JSON, XML).
4-Loose Coupling – Reduce dependencies between components.
How does Modular Design help with flexibility?
making it easier to modify, replace, or update without affecting the entire system. (when doing perfective maintenance)
How does Using APIs help with flexibility?
may have external tools that help with adapting with changes
How does Configuration Files help with flexibility?
By modifying the settings of them making it easier for the software t adapt
How does Loose Coupling Files help with flexibility?
If components are loosely coupled, a change in one part of the system won’t break the rest.
(same as modularity)
TSS stands for ?
Teacher Support Software
What is testability in McCall’s Product revision category?
The testing of an information system as well as its operation.
What are testability requirements for the ease of testing related to?
Special features in the programs that help the tester.
1- Predefined Intermediate Results and Log Files that help testers understand what happened at each step.
2-Automatic Diagnostics Before the System Starts (system checks itself)
3-generate reports about detected faults
How to Improve Testability?
1-Write Clean, Modular Code
2-Use Logging and Debugging Tools – Make it easy to track software behavior.
3-Automate Testing
4-Implement Error Handling (Ensure meaningful error messages help debugging.)
Give examples on automated testing tools and their usage
1-Selenium (for web apps)
2-JUnit (for Java apps)
3-PyTest (for Python)
What is portability in McCall’s Product transition category?
Portability is the ability of software to work on different devices and operating systems.
What does software portability focus on?
It focuses on adapting a software system to different environments, including different hardware and operating systems.
What is reusability in McCall’s Product transition category?
Refers to the ability of software components to be reused in other applications.
How does software reusability help in development?
It helps save resources by shortening the project period and providing higher-quality modules reduce cost and reduce risk
How does the benefits of higher quality appear?
SW faults have already been detected by SQA activities performed previously on it
Who insures reusability of the software?
Development team
What is interoperability in McCall’s Product transition category?
The ability of software to connect and work with other software.
What does interoperability focus on?
creating interfaces with other software systems or equipment firmware(البرامج الثابتة)
What can interoperability requirements specify?
1- They can specify the names of software or firmware for which an interface is required
2-Output structure(output of the system so that it can interface with other systems and use it as input) accepted as standard in a specific industry or applications area.
What do alternative models of software quality factors propose?
They suggest renamed or additional software quality factors beyond McCall’s model.
How many quality factors did some SQA professionals propose? other than McCall’s
One model proposed 12 factors, while another proposed 15 factors.
How many new quality factors were suggested in total?
Five new factors were suggested.
Evans and Marciniak offered how much ? what are they?
2
Verifiability and Expandability
Deutsch and Willis offered how much ? what are they?
3
Safety
Manageability
Survivability
what did they both remove?
testability
What is Verifiability in Evans and Marciniak’s software quality factors?
refers to design and programming features that enable efficient and easy verification of the design and code structure of the system
What are the design and programming features enable efficient and easy verification of the design and code structure of the system?
1-modularity
2-simplicity
3-adherence to documentation and prog guidelines
What does verifiability refer to?
This does not refer to outputs; rather, structure of code, design elements and their dependencies (coupling , pattern , cohesion)
What is Expandability in Evans and Marciniak’s software quality factors?
Refer to future efforts that will be needed to
1-serve larger populations
2-improve services
3-add new applications in order to improve usability.
Which quality factor does Expandability look like from McCall’s?
flexibility
What is Safety in Deutsch and Willis’s software quality factors?
1-address conditions that could bring the equipment or application down
2-setting alarms or sounding warnings.
What is Survivability in Deutsch and Willis’s software quality factors?
1-refer to the continuity of service .
2-minimum time allowed between failures .
3-maximum time permitted for recovery .
Which quality factor does Survivability look like from McCall’s?
Reliability
What is Maximum Recovery Time ?
The longest acceptable time for the system to fully recover after a failure.
What is Minimum Downtime ?
The least amount of time the system is expected to stay down after a failure.
What is Manageability in Deutsch and Willis’s software quality factors?
refers to administrative tools that support software modification during development and maintenance.
What are the tools used in Manageability ?
1- tools primarily administrative control versions, configurations and change management / tracking.
2-We must have tools to manage versions and various configurations that may vary from customer to customer
