Page 12 - DCAP405_SOFTWARE_ENGINEERING

Unit 1: The Evolving Role of Software

Notes
What happens to the minimum failure rates?
Did u know?

The minimum failure rate rises and the software deteriorates due to induction of frequent
changes.

Software is Custom Built and Not Designed Component Wise

Software is designed and built so that it can be reused in different programs. Few decades ago
subroutine libraries were created that re-used well defined algorithms but had a limited domain.
Today this view has been extended to ensure re-usability of not only algorithms but data
structures as well. Thus, the data and the processes that operate on this data were combined
together to be able to use later on.

1.2.1 Program vs. Software

Software is more than programs. It comprises of programs, documentation to use these programs
and the procedures that operate on the software systems.
Figure 1.3: Components of Software

Programs Documentation

Operating procedures

A program is a part of software and can be called software only if documentation and operating
procedures are added to it. Program includes both source code and the object code.
Figure 1.4: List of Documentation Manuals

Formal
specification
Analysis/specification Context diagram

Data flow
diagrams
Flowcharts
Documentation

manuals Design
Entity Relationship Diagrams
Source code listings
Implementation

Cross-reference listing

Test data
Testing
Test results

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