Investigating and Improving a COTS- Based Process M. Morisio UMD, College Park C. Seaman UMD, Baltimore County and Fraunhofer Center MD A. Parra, S. Condon - Computer Science Corporation V. Basili UMD, College Park Fraunhofer Center MD S. Kraft NASA Goddard Space Flight Center
Context zNASA Goddard - Flight Dynamic Division z Software staff zRelatively stable domain yground software - flight dynamic for earth satellites zGood software maturity ySEL started in the 80s yrecommended approach to software development zHigh levels of reuse from project to project yup to 90% reuse level zShift to COTS based development in the mid 90s zEvidence that existing process did not fit
SEL COTS study zCOTS Definition ysoftware product, supplied by a vendor, yintegrated into the system to provide operational functionality yor delivered with the system to sustain maintenance efforts. zCOTS encountered yDomain specific packages for attitude and orbit determination, mission control, mission planning zGoal yUnderstand issues in COTS based development and improve the process yTo improve it xproposed process(1995) xthe actual process (1996-7) xnew proposed process (1998-9)
Proposed Process zFrom literature and recommended approach RequirementsDesign Vendor Coding, Integration COTS identification COTS selection
The actual process RequirementsDesign Vendor Coding COTS identification COTS selection Design glueware and integration Non-COTS development Integration Glueware, interfaces
Activity Change zKey activities yIntegration of COTS yEvaluation/selection of COTS and modification of requirements yInteraction with vendor - documentation of product, commercial negotiations, procurement zModified activities yRequirements - COTS provided vs. built internally yDesign - how to integrate vs. how to decompose zReduced Activities yCoding, debugging - less code produced yUnit testing and code inspections no source code available
Other Issues zDependence on vendor yslippage in release of COTS ydocumentation (unavailable, incorrect, vaporware,..) yupgrades to COTS yvendor not responsive zLearning curve for COTS zLess formal process ywhen traditional process is not suitable
New Proposed Process RequirementsDesignCoding Make vs. Buy Requirements analysis COTS identification and selection Feasibility study Design glueware and integration Incompatibility analysis Integration Glueware, interfaces Review make vs. buy
Recommendations yMake vs. buy decision xCan the project use COTS? Formalize this decision, considering xflexibility in requirements xvendor dependence xfeasibility of integration xcost/schedule/effort development maintenance yCOTS Selection xAnticipated in requirements phase xIn parallel with requirement analysis, COTS familiarization
Recommendations yFeasibility study xPrototype high level architecture, xFirst hand experience with COTS (functionality, vendor) Integration problems Costs, risks yDesign xDeeper level design of glueware and integration xIntegration issues interaction / dependency model incompatibility analysis xReview costs and risks
The COTS Selection Process Dealing with Integration Issues zEvaluate candidate COTS products ywith respect to potential incompatibilities zIdentify the integration problems ycaused by the incompatibilities zIdentify the integration solutions ywith respect to their estimated size zCompute the effort ybased on the solution size and the organization productivity zCompare the candidate COTS products ywith respect to the total integration effort
Recommendations zNew roles yCOTS team xkeeps history of COTS usage xconsults to projects on COTS evaluation and selection techniques procurement licensing yInterface with vendor xat project level
Research method zStructured interviews to 15 projects zInterviewer + scribe zQuality checks yinterviewer and scribe yinterviewer and interviewee zModeling of actual process yconstant comparison method
Conclusion z15 projects using COTS analyzed at NASA zIssues yrequirements, COTS selection and design are closely linked yvendor interaction and dependency yintegration zTo address these issues ymake vs. buy decision yrequirements, (part of) design and COTS selection together yprototype