Misra, maintenance engineering and maintainability an introduction, chapter 46, handbook of performability engineering, springer, 2008. Software maintenance is an expensive activity that consumes a major portion of the cost of the total project. This document is a first step towards the construction of a maintainability prediction model. In engineering, maintainability is the ease with which a product can be maintained in order to. Reliasoft offers software blocksim and training that address the topic of system maintainability analysis. The software maintainability index mi is a singlevalue indicator for the maintainability of a software system. It identifies a set of software measures based on correlations published in empirical studies. Quality assessment remains at the forefront of both software research and practice, with many models and assessment methodologies proposed and used over time. Software functional quality reflects how well it complies with or conforms to a given design, based on. This book provides the guidelines and fundamental methods of estimation and calculation needed by maintainability engineers. Can we apply the maintainability index calculation formula. Maintainability is defined as the probability of performing a successful repair action within a given time. Can we apply the maintainability index calculation formula for the objectoriented software.
Maintainability index c alculates an index value between 0 and 100 that represents the relative ease of maintaining the code. Every time i come across a procedure or code file with a lines of code i just want to sentence the creator to. It also covers the management of maintainability efforts, including issues of. The software maintainability index revisited citeseerx.
Maintainability index is a software metric which measures how maintainable easy to. Mar 01, 2020 we present a longitudinal study on the longterm evolution of maintainability in opensource software. Measuring maintainability index of a software depending on. The origins of contemporary reliability engineering can be traced to world war ii.
We present a longitudinal study on the longterm evolution of maintainability in opensource software. Last week, elsevier cut off thousands of scientists in germany and sweden from reading its recent journal articles, when negotiations over the cost of a. Occasionally ill go look at my methods with a low maintainability index low bad for this one. The maintainability index is calculated as a factored formula consisting of lines of code, cyclomatic complexity and halstead volume. One of the exit criteria of the engineering, manufacturing and development emd phase is demonstrating reliability. Maintainability is a multifaceted quality attribute each of the facets must be analyzed to objectively measure it. This is a quick note about the maintainability index, a metric aimed at assessing software maintainability, as i recently run into developers and researchers who are still using it. Difficulttomaintain source code is a big problem in software development today, leading to costly delays and defects.
Quality assessment remains at the forefront of both software research and practice. Some of them helped create and shape standards such as iso 9126 and 25010, which are well established today. Sei maintanability index objectscriptquality cachequality. Reliasoft offers software blocksim and training that address the topic of system maintainability.
In the context of software engineering, software quality refers to two related but distinct notions. Software functional quality reflects how well it complies with or conforms to a given design, based on functional requirements or specifications. This report describes the maintainability index as good and sufficient predictors of maintainability, and potentially very useful for operational department of defense systems. A measure of effort must include time, resources and expertise. Measuring software maintainability is nontrivial and there exists no single metric to measure it accurately. Maintainability and flexibility at the software level are of predominant importance to drive innovation at the business process level. Testability the presence of an effective test harness. Alrafidain university college, computer engineering.
With maintainable software, it is easy to modify parts of the software, meet user or customer requirements in a shorter time and manage the. Additionally, the ram attributes impact the ability to perform the intended mission and affect overall mission success. Maintainability index report inappropriate project. Calculate code metrics visual studio microsoft docs. Maintainability index is a software metric which measures how maintainable easy to support and. May 26, 2011 maintainability index calculates an index value between 0 and 100 that represents the relative ease of maintaining the code. The standard definition of reliability is the probability of zero. Almost without fail, the methods in my project with the lowest maintainability index are the ones most in need of a rewrite and the hardest to read or maintain. Reliability, maintainability, and supportability is a reference for systems engineers and graduate students hoping to learn how to effectively determine and develop appropriate requirements so that designers. However, existing definitions of maintainability, such as the halstead volume, mccabes cyclomatic complexity or the sei maintainability index provide a very poor understanding of what maintainability is how it.
Maintainability index calculates an index value between 0 and 100 that. This maintainability index mi has evolved into numerous variants and has been successfully applied to a number of industrial strength software systems. The mdemo would be implemented to continue reading. In software engineering, these activities are known as software maintenance cf. Maintainability ieee conferences, publications, and. Collectively, they affect both the utility and the lifecycle costs of a product or system. The following list shows the code metrics results that visual studio calculates. Maintainability index is a software metric which measures how maintainable easy to support and change the source code is. Maintainability demonstration mdemo is a formal process conducted by the product developer and the end customer to determine whether specific maintainability contractual requirements have been. The importance of maintaining software updates the main benefits of maintaining software updates are that security remains on point, usability is firing on all cylinders, and your software is compatible with other all the software you use. Ability of a computer program to be retained in its original form, and to be restored to that form in case of a failure. Code metrics is a set of software measures that provide developers better.
Closely related concepts in the software engineering domain are evolvability. Maintainability index is calculated with certain formulae from linesofcode measurement. We quote the ieee standard glossary of software engineering terminology. Maintainability means fixing, updating, servicing and to modify the system or update the software for performance improvements or for the correction of faults. In software engineering, these activities are known as software. Reliability, maintainability, and availability ram are three system attributes that are of great interest to systems engineers, logisticians, and users. Focuses on the core systems engineering tasks of writing, managing, and tracking requirements for reliability, maintainability, and supportability that are most likely to satisfy customers and lead to success for suppliers this book helps systems engineers lead the development of systems and services whose reliability, maintainability, and supportability meet and exceed the expectations of. Idaho national engineering and environmental laboratory in 1991 oman and hagemeister introduced a composite metric for quantifying software maintainability. Longitudinal evaluation of opensource software maintainability.
Read the first chapter from building maintainable software, java edition, to learn exactly what maintainability means and how it has an impact on business. Focuses on the core systems engineering tasks of writing, managing, and tracking requirements for reliability, maintainability, and supportability that are most likely to satisfy customers. Read the first chapter from building maintainable software, java edition. Software maintainability standard cisq consortium for. The maintainability index mi is a compound metric designed at the university of idaho in 1991 by oman and hagemeister. If you search for more detail, will discover that the equation have to be cabibrated for a specific language. Developing maintainable software software sustainability. Its objectives are to define the concept of maintainability, to describe the factors. A method can be complex but as long as there are unit tests for it, it is much simpler to maintain. If you search for more detail, will discover that the equation have to be cabibrated for a. This paper describes a methodology based on a digraph and matrix approach for developing the maintainability characteristic indexof a software component. This document is a first step towards the construction of a maintainability. Writing elegant code and the maintainability index. How to effectively define and measure maintainability.
Think twice before using the maintainability index arie van. Maintainability demonstration mdemo is a formal process conducted by the product developer and the end customer to determine whether specific maintainability contractual requirements have been achieved i. Developing maintainable software helps reduce technical debt. For this reason, many applications are replaced simply because the overhead to modify them becomes prohibitive. Maintainability wikimili, the best wikipedia reader. The maintainability index is calculated with certain. Center for systems and software engineering maintainability index variation among php, java, and python open source projects celia chen 1, lin shi 2, kamonphop srisopha 1 1 computer science. Refactoring and reengineering are practices to improve a. It is, was constructed a model based in observation and adaptation. Color coded ratings can be used to quickly identify trouble spots in your code. This is not a fixed industry set of rules, but rather a combination of them that works for the requirement of your organization application and team. Maintainability index calculates an index value between 0 and 100 that represents the relative ease of maintaining the code.
The maintainability index is given as a polynomial equation composed of. Several static analysis and software development tools, including. One of the exit criteria of the engineering, manufacturing and development emd phase is demonstrating reliability, availability, maintainability, and sustainment features are included in the design of a system. Think twice before using the maintainability index arie. The software maintainability index revisited semantic scholar. For information about how to generate code metrics data in visual studio, see how to. Various activities carried out during maintenance include the addition of new features, deletion. Software engineering stack exchange is a question and answer site for professionals, academics, and students working within the systems development life cycle. Maintainability and reliability work together is developing design solutions for a system. Arie van deursen software engineering in theory and practice.
Ultimately the maintainability index is what works for your specific case. Reliability, availability, and maintainability ram or rma are system design attributes that have significant impacts on the sustainment or total life cycle costs lcc of a developed system. Maintainability is a multifaceted quality attribute each of the facets must be analyzed to. Software that is written without maintainability in mind requires about four times as much effort to maintain than it did to develop. Mi and minc maintainability index virtual machinery. The maintainability index attracted quite some attention, also because the software engineering institute sei promoted it, for example in their. Maintainability index mi mi is a singlenumber value for estimating the relative maintainability of the code. In general any software development manager is familiar with this definition of effort as it applies to creating software. Maintainability index is a software metric which measures how maintainable. The software maintainability index mi is a singlevalue indicator for the. The maintainability index is calculated with certain formulae from linesofcode measures, mccabe measures and halstead. Apr 20, 2016 difficulttomaintain source code is a big problem in software development today, leading to costly delays and defects. Nov 20, 2007 why dont you consider unit testing coverage to be a part of the maintability index.
Points 1, 2, and 3 shown in the figure identify the mean, median, and maximum corrective timetorepair, respectively. Maintainability also includes the addition of new functionality or the adaptation of software to meet new requirements for the customer needs. Understanding object oriented software engineering stefan sigfried. Think twice before using the maintainability index. Why we dont use the software maintainability index cqse blog. Reliability, maintainability, and supportability wiley. Reliability, availability, and maintainability the mitre. See the white paper for more information on the calculations. Maintainability index variation among php, java, and. This measure is based on measurements the authors performed on a number of software systems and calibrating these results with the opinions of the engineers. Citeseerx document details isaac councill, lee giles, pradeep teregowda. Closely related concepts in the software engineering domain are evolvability, modifiability, technical debt, and code smells. These core facets can be broken down further, to gain further insight into the maintainability of the application. However, existing definitions of maintainability, such as the halstead.
It also covers the management of maintainability efforts, including issues of organizational structure, cost, and planning processes. Best practices and lessons learned 7 8 ensure persistent, active engagement of all stakeholders. Maintainability has previously been described mainlyin two ways, either informally or as a function of directly measurable attributes. Last week, elsevier cut off thousands of scientists in germany and sweden from reading its recent journal articles, when negotiations over the cost of a nationwide openaccess agreement broke down. Maintainability index mi article cited from wikipedia maintainability index is a software metric which measures how maintainable easy to support and change the source code is. A key to effective serviceability and maintenance management blanchard, benjamin s. Chug, software maintainability prediction using machine learning algorithms, softw. Maintainability feature of a software increases quality of it. Can we apply the maintainability index calculation formula for the. Some of the commonly used maintainability engineering terms are portrayed graphically in the figure below as a maintainability function derived as illustrated for the case where the pdf has a. Filter by location to see maintainability engineer salaries in your area. Developing maintainability index of a software component. Maintainability index mi projectcodemeter software sizing. Closely related concepts in the software engineering domain are evolvability, modifiability, technical debt, and.
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