What are the three categories of entities we measure in software engineering?
- Product: The software itself.
- Process: The steps and mechanisms to develop it.
- Project: The administrative part of the endeavor.
What is Reliability in the context of software quality?
The ability of the software product to perform its required functions under stated conditions for a specified period of time.
What is MTBF and what does it measure?
Mean Time Between Failure. It measures reliability by calculating the average time between successive failures.
What is MTTR?
Mean Time To Repair. The average time taken to repair the machine/software after a failure occurs.
Define Software Correctness.
The degree to which software performs its specified function, often measured in defects per KLOC (Thousand Lines of Code).
What is Maintainability?
The ease with which a software product can be modified to correct errors, meet new requirements, or adapt to a changed environment.
What is MTTC?
Mean Time To Change. An indirect measure of maintainability defined as the time taken to analyze, design, implement, test, and distribute changes.
What is Software Integrity?
The degree to which unauthorized access to software components (program, data, documents) can be controlled.
What are the two attributes used to measure Software Integrity?
- Threat: Probability of a particular attack at a given time.
- Security: Probability of repelling an attack.
What is Defect Removal Efficiency (DRE)?
A metric indicating the ability to detect errors before delivery.
Formula: DRE = E / (E + D)
(E = errors found before delivery, D = defects found after delivery).
What is the ideal value for Defect Removal Efficiency (DRE)?
The value approaches 1 as fewer defects (D) are found after delivery.
What are Direct Measures in software metrics?
Metrics that can be observed directly, such as Cost, Effort (Person-Months), Lines of Code (LOC), Execution Speed, and Memory Footprint.
What are Size-Oriented Metrics?
Metrics normalized by the size of the software, typically using Lines of Code (LOC). Examples: Errors per KLOC, Defects per KLOC, Cost per KLOC.
What are the disadvantages of using Lines of Code (LOC) as a metric?
- Language dependent.
- Penalizes well-designed but shorter programs.
- Difficult to measure in early phases.
- Depends on formatting/style.
What is a Function Point (FP)?
A unit of measurement expressing the amount of business functionality an information system provides to a user, independent of technology or language.
What are the 5 Information Domain Values counted in Function Point Analysis?
- External Inputs (EI)
- External Outputs (EO)
- External Inquiries (EQ)
- Internal Logical Files (ILF)
- External Interface Files (EIF)
Define External Input (EI).
A transaction that moves data from outside to inside the application boundary (e.g., a data input screen).
Define External Output (EO).
A transaction that moves derived or processed data from inside to outside the application boundary (e.g., a report with calculations).
Define External Inquiry (EQ).
A user-initiated request where data moves from inside to outside with no processing or derivation of data (raw retrieval).
Define Internal Logical File (ILF).
A group of logically related data that resides entirely within the application boundary and is maintained by the application’s External Inputs.
Define External Interface File (EIF).
A group of logically related data that resides outside the application boundary and is used for reference only (maintained by another application).
What are Data Elements (DE) in Function Point Analysis?
Unique, user-recognizable, non-recursive fields (pieces of information) that move across the boundary during a process.
What is a File Type Referenced (FTR)?
A file type (either an ILF or EIF) that is read or maintained by a transactional function (EI, EO, EQ).
What is COCOMO?
Constructive Cost Model. An empirical model mainly used to estimate software development effort and cost based on project size (LOC).
