1. Software engineering

2. McCall’s Quality Factors
Revision
Adaptation
Maintainability
Flexibility
Testability
Portability
Reusability
Interoperability
Operation
The attributes that provide an indication of quality remain the same.
Correctness
The extent to which a program satisfies its specifications and fulfills the customer’s mission objectives
Reliability
The extent to which a program can be expected to perform its intended function with required precision.
Efficiency
The amount of computing resources required by a program to perform its function
Integrity
Extent to which access to software or data by unauthorized persons can be controlled.
Usability
Effort required to learn, operate, prepare input, and interpret output of a program
Maintainability
Effort required to locate and fix an error in a program
Flexibility
Effort required to modify an operational program
Testability
Effort required to test a program to ensure that it performs its intended function
Portability
Effort required to transfer the program from one hardware and/or software system environment to another.
Reusability
Extent to which a program can be reused in other applications
Interoperability
Effort required to couple one system to another.
Correctness
Reliability
Usability
Integrity
Efficiency

3. Operation Correctness
The extent to which a program satisfies its specifications and fulfills the customer’s mission objectives
Reliability
The extent to which a program can be expected to perform its intended function with required precision.
Efficiency
The amount of computing resources required by a program to perform its function

4. Operation
Integrity
Extent to which access to software or data by unauthorized persons can be controlled.
Usability
Effort required to learn, operate, prepare input, and interpret output of a program

5. Revision Maintainability
Effort required to locate and fix an error in a program
Flexibility
Effort required to modify an operational program
Testability
Effort required to test a program to ensure that it performs its intended function

6. Adaptation Portability
Effort required to transfer the program from one hardware and/or software system environment to another
Reusability
Extent to which a program can be reused in other applications
Interoperability
Effort required to couple one system to another

7. Measuring Quality
Correctness
Maintainability
Integrity
Usability

8. Measuring Correctness
Degree to which software performs its function
Defects/FP or Defects/KLOC
Defects verify lack of conformance to requirements
These are problems reported by the user after release
Defects are counted over a standard period of time, typically during the first year of operation

9. Maintainability
The ease with which a program can be corrected if an error is encountered, adapted if environment changes, enhanced if the customer requires an enhancement in functionality
Its an ‘indirect measure’

10. Measuring Maintainability
MMTC – mean time to change
Time it takes to analyze the change request, design an appropriate modification, implement the change, test it, and implement it
Spoilage – cost oriented metric
The cost to correct defects encountered after the software has been released to the users

11. Integrity
Software’s ability to withstand attack (both accidental and intentional) to its security.
To measure integrity, two additional attributes are needed.
threat
security.

12. Integrity
Threat is the probability (derived or measured from empirical evidence) that an attack of a specific type will occur within a given time
Security is the probability that an attack of a specific type will be repelled.
Integrity = Σ [(1-threat) x (1-security)]

13. Usability It is a measure of user friendliness
Can be measured in terms of 4 characteristics:
Physical or intellectual skill required learn the system
The time required to become moderately efficient in the use of system
The net increase in productivity
A subjective assessment

14. Defect Removal Efficiency
It’s the valuable at both the project and process level.
Effectiveness of the quality processes during development as a percentage of total defects
DRE = E/(E+D)
E – errors found before delivery
D – errors found after delivery (typically within the first year of operation)

15. Defect Removal Efficiency Capers Jones 1997
Sample Size – 1500 Projects