Quality of Open Source Softwares An Issue of Concern

Transcription

1 Computing For Nation Development, February 25 26, 2010 Bharati Vidyapeeth s Institute of Computer Applications and Management, New Delhi Quality of Open Source Softwares An Issue of Concern Anil Kumar 1, Vibhakar Mansotra 2 and Dalip Bhat 3 1 Department of Computer Science & IT University of Jammu, akticku@yahoo.com 2 Department of Computer Science & IT University of Jammu, vibhakar20@yahoo.co.in 3 IGNOU Regional Center Jammu: daliprak@gmail.com ABSTRACT The computer software in today s world is linked to almost every human being. The software development companies are continuously developing/modifying/ updating their softwares as per the changing needs and requirements. Not only this, a number of software houses are putting their products including the source codes on web for the attention of everyone interested in the process of development of software & its quality. Such softwares, which are posted on the web for the attention of others, are what we term as open source softwares. Over a period of time open source software has become a major issue of concern for the computer professionals. It is because, initially the software is developed by an individual or a group and is put on the web for the attention of others for improvement or giving suggestions to improve or refine these software's. However, it is envisaged that there is hardly an improvement in the services/quality of software which is available as an open source. It is in this direction that in this paper the authors have tried to analyze and understand the quality of the software available free of cost as an open source. The software quality is highly related to software development. Beyond a certain point, it is difficult to increase the quality without increasing either the cost or time of completion or both for the software under development. To alter any of these may lead in compromising the quality of software. Despite research advancements, even when faithfully applying techniques for fault finding, software quality remains an issue. In this paper the authors have tried to analyze the quality of open source software. The main focus has been driven in finding the different type of errors for which various tools/analyzers such as code analysis, code coverage have been used. The source code of various software s have been tested for their validity, quality, effectiveness & efficiency by the use of these analyzers. The results obtained have been analyzed and presented in the form of graphs and tables. Finally the paper concludes with various observations and suggestions in terms of enhancing and preserving the software quality. KEYWORDS OSS, Function Coverage, Uncovered decisions, Software Quality. 1.0 INTRODUCTION An open source software should have the following four characteristics: Copy and distribution Usage as per the wish and requirements of the user Modification and redistribution. Separation of the binary version of the source code and the software binary version of the software and the source code can be separated freely. The majority of OSS projects, use development practices, models and methods which are far away from those recommended by the classical software engineering models[1], for example software development life-cycle models like waterfall and the spiral. The main idea behind the development model of OSS is simple. Any person or group of persons who are in need of a desiring to computerize a process/ processes may design and develop a software product to address their needs. The software product so developed by a person or a group may be released as an open source software product. this product goes online along with its source code, and is open for others for contribution inn terms of fixing the bugs or functional improvement for the product. The OSS development begins as soon as the other people start contributing in this software product. The contributions from the other people when incorporated in the source code leads to new version of the software product. However the incorporation of the modification and improvements on this open source software can t be done independently by the other people without seeking consent of the original creators of the software. Advantage of the current open source development processes is that it could minimize the cycle time, cost and infrastructure of the software like O.S, languages tools, compilers, editors and distribution middleware etc. 2.0 SOFTWARE QUALITY When a software meets the user requirement like flawless performance, easy to modify and easy to use, it is called quality software. [2] Quality of software has three dimensions: [3] Product operation: Correctness, Reliability, and Efficiency. Product transition: Portability, Interoperability. Product Revision: Modification, Maintainability, and Testability. We can say that Software Quality is like a backbone in the field of Open Source Software development. Barry Boehm describes it as achieving high levels of user satisfaction, portability,

2 maintainability, robustness and fitness for use. [4] Quality is an important aspect of any product. Without quality a product can t be successful. There is a need of continuous improvement in quality for fulfilling the needs of customers. The route to the productivity can be achieved through quality in a cost effective way. Quality for different systems differs because the requirements are different in user s perspective. Although the current available software models do address the quality concerns of the software products yet there are number of software quality issues, which need to be addressed fully. R. GEOFF DROMEY[5] has given two approaches for tackling quality problems in software products. These are curative approach and preventative approach. In case of curative approach shown in figure A, the focus is on Testing. Defects are identified both by developers and users and subsequently fixed. In case of preventative approach (Figure B), there are three aspects to peep in: - first to anticipate and prevent the occurrence of defects., - second, to use processes (including formal inspections and prototyping) to discover and remove deficiencies and defects as early as possible in the development process. - third, to use tools (e.g., static analyzers, automated testing and other tools) where possible As per John Moses[6] most external of software quality attributes are conceptually subjective. For example, maintainability is an external software quality attribute, and it is subjective because interpersonally agreed definitions for the attribute include the phrase the ease with which maintenance tasks can be performed. Subjectivity clearly makes measurement of the attributes and validation of prediction systems for the attributes problematic. The authors highlight that software developers generally think that they do not need the fundamental measurements of software quality i.e. the ability to measure quality directly. It is because the problem has already been critically analyzed using heroically models and reported nearly thirty years ago. The software developers always look for a software quality model to measure the quality of the software product till date there is no such mathematical model which can be used to measure the quality of the software product of to the lowest level of the attributes. Though the authors also do not propose any such model however an attempt has been made to study and analyze the quality of the software products, particularly the open source software, in terms of their functional usage requirement of actual source code and decisional structures 3.0 DATA COLLECTION/ SOURCES For the purpose of carrying our study for analyzing the quality of software products the authors searched for available open source softwares. After an extensive search on the web an open source software, MSLOGO was located and treated as data for studying its quality. MSLOGO is and education an programming language developed in C++ available as an open source software. This is an interpreter based programming language developed particularly for the kids of the age of six years an above the software is used to draw geometric figures along with understanding and logic skills. This open source tool has been completely explored in terms of its composition like the number of functions, the number of source lines, comments, blank lines, and subprograms. For the purpose of computation of number of functions, source lines, comments and blank lines a tools (code count) have been used. This tool (code count) has also been taken form web as an open source product. Similarly for the purpose of analyzing like finding uncovered functions and uncovered conditions/decision in the entire source code, another tool, (Bullseye Coverage) has been used. This tool has also been taken for the web. the source code like 4.0 STUDY AND ANALYSIS a) USING CODE COUNT : The authors have tried their best to test and analyse the collected source code of the software MSLOGO suing code count this product has been completely decomposed in terms of sub programmes,number of functions in sub programme, number of source lines, comments, and balnk lines. The complete software (MSLOGO) is the collection of 80 different sub programs of different sizes comprising of about line of code. Due to the complexity of studying all the eight and representing all 80 subprograms the authors have

3 Quality of Open Source Softwares An Issue of Concern restricted the study and analysis of those only nineteen subprogram s who are all above the storage size of 11kilobyes thus the rest of the sixty one subprograms have not been used for study and analysis. The detailed description of the number of subprogram s functions, source lines, Comments etc as obtained using the code count is given in table I below. STORAGE SIZE (KBs) SUB ROGRAME NAME NO. OF SOUCE LINES NO. OF UNCTIONS NO COMMENTS NO. BLANK TOTAL LINES 11,534 DDEWIND.CPP ,817 DEVWIND.CPP ,221 ERROR.CPP ,770 EVAL.CPP ,123 FILES.CPP ,217 FIXEDIT.CPP ,387 FUNC.H ,699 GBMBMP.CPP ,546 GBMGIF.CPP ,551 GRAPHICS.CPP ,620 INIT.CPP ,954 LISTS.CPP ,748 LOGOCORE.H ,048 LOGODATA.CPP ,903 MAIN.CPP ,342 MATH.CPP ,178 NETWIND.CPP ,464 PARSE.CPP ,487 WRKSP.CPP Table-I It clearly observed form the above table that there is no uniformity followed for writing subprogram s inn terms of source lines function, comments and blank lines as on can clearly see at the serial number one and two that there is no uniform pattern / matching in the all above features of a program. Similar is the observation for the rest of the sub programs. For the purpose of clarity the authors have represented few attributes from this table in the form of graphs in the figures I, II and III. Figure I :The graph shown in this figure shows comments verse total number of lines. This is clear-cut observation that there is no rule /model uniformity which have been followed for inclusion of comments in writing a program. Figure -I Figure II :The graph shown in this figure shows the total number of functions verses number of lines in sub program. This graph also clearly revels that there is no specify relation between these two parameters.the graph clearly reveals that the developer of the source code (MSLOGO) ahs not kept in mind any model/ pattern which should have been followed for composing a subprograms into a number of functions Figure -II Figure III :The graph shown in this figure shows Blank lines verse number of lines on can clearly observe in this graph that at many subprograms there are good number of blank lines which have been included the subprograms unnecessary there by raising the size of the sub program good number. Figure -III

4 b) USING BULLSEYE COVERAGE For the purpose of carrying out analysis of the source code (MSLOGO) in terms of usage of functions included in the subprogram as a part of code and also the execution of the number of control like decision and count structures, the authors have used another tool: BULLSEYE COVERAGE using this tool all the sub programmes have been have been subjected for finding if there are any uncoveed functions and un covered conditions decsions. Detail observations for ecah sub programme is show in the Table II below. SUB PROGRAME NAME NO. OF EXE SOUCE LINES NO. OF FUNCTIONS UNCOVERED CONDITIONS/ DECISIONS DDEWIND.CPP UNCOVERED FUNCTIONS It is clearly observed form this table that there are many subprogrames which possess a number condtion/decision which are never executed. Simillly there are subprogrames which do include certain function which are never called used. The figures IV&V below shows more clear observation about these two parameters. Figure IV :The graph shown in this figure shows: is a graphical representation of number of uncovered conditions / decisions verses number of source lines. This clearly shows that there are so many uncovered conditions/ decisions in almost all the subprograms. This is a clear indication that the software developers while developing software do not understand the exact needs and requirements of the system for which the product is being developed. DEVWIND.CPP ERROR.CPP EVAL.CPP FILES.CPP FIXEDIT.CPP FUNC.H GBMBMP.CPP GBMGIF.CPP GRAPHICS.CPP Figure -IV Figure V : Here in this graph one can easily observed that there are a number of subprogram which do not make use some their functions at all which again is a drawback on the part of the software developer This also leads the unnecessary increase in the size of code at the cost of time and cost. In other words the observation leads to the same conclusion that no efforts are made to exactly know what the system requires at what point of time. INIT.CPP LISTS.CPP LOGOCORE.H LOGODATA.CPP MAIN.CPP MATH.CPP NETWIND.CPP PARSE.CPP WRKSP.CPP Table-II Figure -IV Continued on Page No. 424

5 Quality of Open Source Softwares An Issue of Concern 5.0 CONCLUSION Source code analysis tools provide an automated method to detect a significant number of software bugs or security vulnerabilities right at the contributors/developers desk in case on open source. The above testing of the code has show that In spit of the fact the open source software s developers pay utmost attenuation for the quality of the product but code analysis code count and Bullseye Coverage in our case have shown that the software still contains vulnerabilities which and compromise the quality of the product 6.0 FUTURE SCOPE The work presented in this paper pertains to only nineteen subprograms the size of which is more that 11 kilobytes. The observations have all been made in this papers with regard to the studies and analysis made on these nineteen subprogram s. clearly there is no hundred percent justification in commenting the quality of the product base on the study of these subprogrammers. The future scope lies in the study of all subprograms of the product irrespective of the size of the subprograms. Not only this as supportive study the confirmations to the observation carried out this paper should also be supplemented by carrying similarly studies inn other software products probably of similar nature 7.0 REFERENCES 1. Elliott, M.S., Examining The Success of Computerization, Movements in the Ubiquitous Computing Era: Free and Open Source Software Movements, in Kraemer, K.L. and Elliott, M.(Eds.), Information Today, Inc., to appear,, Software Engineering by Roger S Pressman, 5th edition. 3. An integrated Approach to Software Engineering-2 nd Edition by Pankaj Jalote. 4. B. Boehm, "Software Engineering Economics," IEEE Transactions on Software Engineering, vol. 10, pp. 4-21, R. GEOFF DROMEY, Software Quality Journal, 11, , John Moses,Software Qual J (2009) 17: DOI /s ISO/IEC TR 9126: Software engineering Product quality, Feller, J., & Fitzgerald, B. (2002) Understanding Open Source Software Development, London: Addison-Wesley.