Page 35 - DCAP305_PRINCIPLES_OF_SOFTWARE_ENGINEERING

Unit 2: Software Processes and Models

• Each phase has well defined inputs and outputs e.g. input to system stage is Requirement Notes
Specification Document (RSD) and output is the design document.
• Easy to use as software development proceeds.
• Each stage has well defined deliverables or milestones.
• Helps the project manager in proper planning of the project.

Disadvantages
• Idealized, does not match reality well.
• Does not reflect iterative nature of exploratory development.

• Unrealistic to expect accurate requirements so early in project.
• Software is delivered late in project, delays discovery of serious errors.
• Difficult to integrate risk management.

• Difficult and expensive to make changes to documents, swimming upstream
• Significant administrative overhead, costly for small teams and projects.

Self Assessment Questions
1. Software is said to be ................... if it uses the available resources in the most efficient
manner.
(a) efficiency (b) maintainability
(c) functionality (d) adaptability
2. ............................ is the ability of the software that should not cause any physical or economic
damage in the event of system failure.
(a) Functionality (b) Adaptability

(c) Dependability (d) Usability
3. The Waterfall model is one of the most used models of ..................
(a) 1964 (b) 1965

(c) 1968 (d) 1970
4. .................... phase transforms the low level design part of software design description into
a working software product by writing the code.
(a) Requirements analysis (b) System design
(c) Implementation (d) Testing phase

5. Testing phase makes the system operational through installation of system and also focuses
on training of user.
(a) True (b) False

2.4 Prototype Model

Prototypes are ‘instruments’ used within the software development process and different
kinds of prototypes are employed to achieve different goals. The ‘product’ prototype has been
variously defined within the prototyping literature and an early definition is that of Neumann
and Jenkins who considers an information systems prototype to be a system that captures the

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