University Report: Analysis of Software Testing Standards (DO-178C)

This report provides a detailed analysis of the DO-178C standard, an international guideline for software development, particularly in the aviation industry. The report begins with an introduction to standards and their importance, focusing on the DO-178C standard as a modification of DO-178B. It discusses the scope of DO-178C, emphasizing its role in the complete software development life cycle (SDLC) from requirements to verification. The report explains the standard's key components, including system requirement analysis, design, and coding, especially in the context of model-based design. It highlights the standard's relevance to software testing, detailing its guidelines for analyses, reviews, and testing of source code and executable code, as well as tool qualification. The report also compares DO-178C with DO-331 and discusses the commonalities and differences between them. The conclusion summarizes the improvements the new standard brings, particularly in using model-based design and its impact on flight software development. The report is a comprehensive overview of the DO-178C standard, offering valuable insights into its application and significance.

Running head: SOFTWARE TESTING STANDARDS
SOFTWARE TESTING STANDARDS
Name of the Student:
Name of the University:
Author Note:

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Table of Contents
Introduction................................................................................................................................2
Discussion..................................................................................................................................2
Scope of DO 178 C................................................................................................................3
Understanding the standard DO 178 C..................................................................................3
Use of DO 178 C....................................................................................................................4
Relevance to software testing.................................................................................................5
Commonalities and differences..............................................................................................5
Conclusion..................................................................................................................................6
References..................................................................................................................................7

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Introduction
Standards are set of guidelines or rules that is needed to be followed in order to develop
something. Almost everything from small products to large aero planes have pre-defined
clear standards that must be followed in order to manufacture them. The Standards Australia
is a non-governmental, non-profit organization that is one of the top bodies to develop new
standards in Australia.
In this report, one such international standard related to software development in
aviation industry will be discussed. The paper chosen talks about the improvement of the
flight software with the help of a new modified standard known as DO 178 C. This new
standard encompasses modern technologies like object oriented technologies, formal methods
and model based design. The standard document chosen describes this standard and talks
about all the changes brought about by the new standard including the objectives, the role of
the standard in testing, life cycle model, the standard framework and related standards. These
rules in the standard can be applied for both the hardware and the software part.
Discussion
The name of the standard being discussed in this report is DO 178 C which is related to the
software development of airplane system. This standard is similar to the DO 178 B standard
which relates to the inflight system software. This document is widely used in the United
States, Australia, Canada and Europe as an International guide for certification based on
which the commercial software based aerospace systems are allowed. The document is
jointly developed and copyrighted by RTCA and EUROCAE and is a replacement of the
earlier DO 178 B standard.
The new standard has little change from the previous DO 178 B except that it brings in the
scope of adding modern technologies like Model based design to it. The standard being

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jointly developed by two organizations from two different countries implements a lot of cross
border ideas and helps in creating an internationally accepted standard. No as such separate
universities were involved in the development of the standard as it was developed by two
dedicated standard developing organizations. The DO 178 C helps in addressing the complete
software development life cycle or SDLC of the flight system, starting from the software
requirements to its verification.
Scope of DO 178 C
The scope or the intent of the standard is to develop a flight software system from scratch
implementing all the steps of the software development life cycle that will help in adding the
model based design objective mapping feature to the existing technology. The standard
promotes the safe implementation of aeronautical software by encompassing modern
technologies. It also addresses upcoming software technologies and trends like model based
design, formal methods and object oriented design of the software. It provides quite clear and
consistent ties with the safety and system processes. It tries to create a software that can
change with the technology.
Understanding the standard DO 178 C
A major issue with the DO 178 B was that it was unable to map its objectives with the model
based design artifacts. This addressing of the model based design mapping was implemented
in DO 178 C. To understand the working of the DO 178 C, the key parts of the software
development life cycle must be understood first. The major three steps involved in
developing a software based on the standard are:
1. System requirement analysis as prescribed in the standard DO 178 C
2. System design process following the standard DO 178 C

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3. Software coding process which will involve the source code of the software written
following the DO 178 C standard.
The main essence of the above mentioned steps is that in a model based design, a model can
be used for design of the system or the software or both and should be made by using the
requirements that is external to the model. This requirements can be a requirement database
or a textual document. The source code for the software can be hand written created directly
from the design model. This is the basic concept of the model based design mapping for
software and system design. The model that is used for designing the system is again reused
for software design and generation of the code.
The next part is the system requirement validation which is also performed according to the
DO 178 C standard. The test cases generated for the system requirement validation are again
reused on the source code, executable object code and the model to collect coverage metric
and perform functional testing. This helps in reducing the cost and increase the quality of the
software system.
Use of DO 178 C
The DO 178 C is very similar to its predecessor the DO 178 B. The main aim of the new
standard DO 178 C is to modify the existing DO 178 B to add extra features and capability to
it. The standard also helps in developing supplements to method specific or document
technology specific guidelines. It also helps in developing document logic for each and every
DO 178 B objective. The DO 178 C standard also maintains some considerations while
modifying the DO 178 B standard. It should try to change the standard with minimum
changes in the text part. The new standard should make the changes to the existing standard
in such a way that it reduces the cost and also not decrease the system safety. The new
standard should also clear out any inconsistencies or errors in the existing standard DO 178 B

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without much alteration. The new standard should meet the documentation need to state the
assurance benefit.
Relevance to software testing
The standard selected in used in both the requirement analysis as well as the requirement
validation and testing part. The DO 178 C plays a very important role in the software testing
phase. The DO 178 C calls out analyses, reviews and testing as suitable verification tools for
requirements, source code, design and executable object code. It gives the procedure and
guidelines to the engineers to analyze, review and test the source code or the software design.
The DO 178 C also gives out guidelines to validate the qualification of a tool used in
software development. For example, an automatic code generator needs to qualify if the
output code generated by it cannot be verified as per the given standards. If the code can be
verified then there is no need for the qualification of the tool. In model based design, as per
DO 178 C only if a tool is used for credit, it needs validation.
Commonalities and differences
The paper talks about the implementation of the DO 178 C standard in place of the old DO
178 B. The document and the paper both discusses the missing aspect of the technology in
the old standard DO 178 B as well as the spaces where it can be improved under the new
standard DO 178 C. The research paper also talks about another standard DO 331 which is
similar to the DO 178 C but adds simulation as an extra way of verification of the models.
The paper talks about the technology that is model based design which can be implemented
using DO 178 C and DO 331. The document and the paper also talks about the tool
qualification aspect of the system which is common in both the files. The tool qualification
ensures that the tool used for developing the system is qualified as per the given standard.
The software development life cycle is also discussed both in the standard document and the

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paper. Both the files talks about the stages of the SDLC and the processes that is needed to be
followed under the standard.
The only difference between the files is that while the research paper talks about the model
based design as the supplemental technology, the normal DO 178 C standard documentation
never mentions the technology name instead refers to it as scope for future technological up
gradation. The document is theoretical whereas the research paper talks about the practical
use of the standard. The document also talks about the developmental framework and the
related standards like DO 248 B and DO 278, whereas the research paper does not focus on
these topics and talks about only the main standard DO 178 C and DO 331 which are being
implemented in the aviation industry.
Conclusion
The introduction of the new standard of DO 178 C added a new system to guide the software
practitioners as how to use simulation and modelling in an effective and robust manner. The
use of model based design as an improvement of the existing standard to add objective
mapping to the system is a new function of the standard DO 178 C. The standard also
implements technologies like formal methods and object oriented technologies. The new
standard also encompasses the whole software development life cycle from software
requirement analysis to software verification. Therefore, to conclude the new standard
provides great improvements for the flight software and also achieves this with minimum
modifications of the original DO 178 B standard.

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References
Potter, B. (2012). Complying with DO-178C and DO-331 using Model-Based Design.
Retrievedfrom https://www.mathworks.com/tagteam/74250_Paper%20Number%2012AEAS-
0090-finalweb.pdf
Brosgol, B., & Comar, C. (2010). DO-178C: A New Standard for Software Safety
Certification. Retrieved from https://apps.dtic.mil/dtic/tr/fulltext/u2/a558107.pdf