The document discusses software quality, particularly through McCall's quality model which aims to bridge the gap between users and developers by outlining quality characteristics. It identifies three major perspectives: product operations, product revision, and product transition, each encompassing specific traits like correctness, maintainability, and portability. Additionally, it explains the hierarchical relationship between quality factors, criteria, and metrics used for assessment.

1. BY: SUNDAS SHABBIR Ahmed Kaim
Khani
1

2. Software Quality:
•Conformance to the users Requirements.
Quality Models:
•Software Quality is described by specific quality models.
Software Quality Models are:
McCall’s Model
•Boehm Model
•FURPS/FURPS+
•Dromey quality Model
•ISO quality Model
FURPS
BY: SUNDAS SHABBIR Ahmed Kaim
Khani 2

3. Introduction:
Jim McCall produced this model for the US Air Force
and the intention was to bridge the gap between users and developers.
McCall Model Developed in 1967-7,
•One of the first , Oldest software quality model.
•Started with volume of 55 quality characteristics ,called them “factors”
•Quality Factors was compressed into 11 main factors.
•McCall Tried to map
user view
developer’s priorities.
BY: SUNDAS SHABBIR Ahmed Kaim
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4. McCall Quality Model:
Three 3 major perspectives.
1. Product Revision (ability to under go Changes)
Maintainability, Flexibility, Testability.
2.Product Transition (adaptability to new environments).
Portability, Reusability, Interoperability.
3.Product Operations( basic Operational characteristic).
Correctness, Reliability, Efficiency, Integrity, Usability
BY: SUNDAS SHABBIR Ahmed Kaim
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5. McCall’s Quality Model Tree
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6. Also known as
McCall’s Quality Model Triangle
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7. McCall’s Quality Model:
Based on 3 types of Characteristics with hierarchical dependency:
1. Factors(to specify): external software view for users.
2. Criteria(to build): internal software view for developers.
3. Measures/metrics (to control): are used for software measurement.
BY: SUNDAS SHABBIR Ahmed Kaim
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8. 1.Product Operations
•Correctness, the functionality matches the specification.
or
Does it do what customer wants?(meeting specification)
•Reliability, the extent to which the system fails.
or
Does it do it accurately all of the time. (successful performance)
BY: SUNDAS SHABBIR Ahmed Kaim
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9. 1.Product Operations conti..
•Efficiency, system resource (including cpu, disk, memory, network) usage.
or
Does it quickly solve the intended problem?(enough computing resources)
•Integrity, protection from unauthorized access.
or is it Secure? (access limitation to people)
•Usability, ease of use
Or
Can I run it? (efforts in learning/operating)
BY: SUNDAS SHABBIR Ahmed Kaim
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10. 2.Product revision
•Maintainability, the ability to find and fix a defect.
Or Can it be fixed?(fixing bugs and errors)
•Flexibility, the ability to make changes required as dictated by the business.
Or Can it be changed?(modifying an operational program)
•Testability, the ability to Validate the software requirements.
Or Can it be tested? (ensuring performance)
BY: SUNDAS SHABBIR Ahmed Kaim
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11. 3. Product transition
•Portability, the ability to transfer the software from one environment to another.
Or Can it be used on another machine?(Platform dependence).
•Reusability, the ease of using existing software components in a different context.
Or Can part of it be reused? (generic coding).
•Interoperability, the extent, or ease, to which software components work together.
Or Can it interface with other system (coupling system)
BY: SUNDAS SHABBIR Ahmed Kaim
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12. Relationship between Quality Factors and Quality Criteria
•Each quality factor is positively influenced by the set of quality criteria,
And the same quality criterion impacts a number of quality factors.
Some quality factors positively impact others.
•An effort to improve the correctness of a system will increase its reliability.
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