Page 60 - DCAP305_PRINCIPLES_OF_SOFTWARE_ENGINEERING

Principles of Software Engineering

Notes According to SOMM the benefits of developing prototype are listed:
1. Communication gap between software developer and clients may be identified.
2. Missing user requirements may be unearthed.

3. Ambiguous user requirements may be depicted.
4. A small working system is quickly built to demonstrate the feasibility and usefulness of
the application to management.
5. It serves as basis for writing the specification of the system.
The sequence of prototyping is seeing in following Figure 3.4.

Figure 3.4: Sequence of Prototyping
Start
Requirements Quick Building Customer
Gathering Design Prototype evaluation of
prototype

Stop
Engineering product Refine Prototype

3.4.2 Problems of Prototyping
In some organizations, the prototyping is not as successful as anticipated. A common problem
with this approach is that people expect much from insufficient effort. As the requirements are
loosely defined, the prototype sometimes gives misleading results about the working of software.
Prototyping can have execution inefficiencies and this may be questioned as negative aspect
of prototyping. The approach of providing early feedback to user may create the impression
on user and user may carry some negative biasing for the completely developed software also.

Software Metrics
Measurement is fundamental to any engineering discipline and software engineering is no
exception. Software metric is a quantitative measure derived from the attribute of software
development life cycle. It behaves as software measures. A software measure is a mapping from
a set of objects in the software engineering world into a set of mathematical constructs such as
numbers or vectors of numbers. Using the software metrics, software engineer measures software
processes, and the requirements for that process. The software measures are done according to
the following parameters

1. The objective of software and problems associated with current activities
2. The cost of software required for relevant planning relative to future projects
3. Testability and maintainability of various processes and products
4. Quality of software attributes like reliability, portability and maintainability, Utility of
software product, User friendliness of a product.
Various characteristics of software measures define:
Objects of Measurement: They indicate the products and processes to be measured.
Source of Measurement: It indicates who will measure the software. For example, software designer,
software tester and software managers.
Property of Measurement: It indicates the attribute to be measured like cost of software, reliability,
maintainability, size and portability.

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