The NASA Space Network (SN), which consists of the geosynchronous Tracking and Data Relay Satellite (TDRS) constellation and its associated ground elements, is a critical national space asset that provides near-continuous, high-bandwidth telemetry, command, and communications services for numerous spacecraft and launch vehicles. The Space Network includes several key ground system elements, one of which is the White Sands Complex Data Interface Service Capability (WDISC). The WDISC has undergone multiple cycles of modification and technology refresh over its lifetime, making test automation an attractive option for reducing system verification and validation cost. This paper considers the implementation of automated testing for the WDISC as a case study in technology sustainment, discusses the principal benefits and challenges of implementing test automation for a legacy system, and presents findings that demonstrate the effectiveness of such automation models.

Detta arbete undersöker migration från legacy-system till en molnbaserad miljö. Legacy-system är ett system som byggts upp under organisationens livstid och är kritiskt för attverksamheten ska fungera. Syftet med arbetet är att undersöka vilka motiverande ochutmanande faktorer som påverkar denna migration och hur dessa faktorer påverkartillvägagångssätt och de beslut som fattas. Den teoretiska bakgrunden bygger på tidigarestudier av legacy till moln-migration, där ett antal faktorer identifieras som viktiga. Därtillbeskrivs fyra områden som är centrala för tillvägagångssättet i denna typ av migration, blandannat arkitektur, val av destination och fyra migrationstyper. Kvalitativa intervjuer hargenomförts för att bidra till en fallstudie av ett stort företag som just nu genomför enmolnmigration. Tillsammans med tillgängligt material har intervjuerna analyserats ochresulterat i en diskussion där vi för vissa faktorer kunnat bekräfta deras påverkan, samtidentifiera ett antal nya. Slutligen visar vi på hur dessa faktorer har påverkat beslut som detundersökta företaget fattat under processen och vilket tillvägagångssätt dessa lett till. Därfinner vi bland annat att faktorer kopplade till säkerhet har haft mest omfattande påverkan påde fyra undersökta områdena.

Organizations that have come to depend on legacy systems face quite a paradoxical problem. Maintaining the system might prove ineffective in accommodating necessary changes, but a system migration project is expensive and incurs a high amount of risk. Organizations are therefore hesitant to respond to the legacy system problem by undertaking action. Legacy system are often not causing their organization any problems at present, but a focus on the future with regard to the legacy system problem is lacking. This results in IT systems reaching an end-of-life state. The research therefore set out to explore a future-oriented perspective on legacy systems by means of observation, a literature review and a survey. The researcher found the key concept of a future-oriented perspective to be that any system that is limiting an organization to grow and innovate can be regarded as a legacy system. A framework to designate legacy status to IT systems is proposed in order to guide practitioners to acknowledge a problematic IT system to facilitate appropriate response at the right time. In relation to a future-oriented perspective, when to designate legacy status is best determined according to the system’s flexibility towards change and the alignment of the system with the business. In that regard, IT systems are end-of-life systems when they are too inflexible to change, and as a result become unaligned with either current operations or a future business opportunity or need.

Enterprises can be empowered to live up to the potential of becoming dynamic, agile and real-time. Service orientation is emerging from the amalgamation of a number of key business, technology and cultural developments. Three essential trends in particular are coming together to create a new revolutionary breed of enterprise, the service-oriented enterprise (SOE): (1) the continuous performance management of the enterprise; (2) the emergence of business process management; and (3) advances in the standards-based service-oriented infrastructures. This thesis focuses on this emerging three-layered architecture that builds on a service-oriented architecture framework, with a process layer that brings technology and business together, and a corporate performance layer that continually monitors and improves the performance indicators of global enterprises provides a novel framework for the business context in which to apply the important technical idea of service orientation and moves it from being an interesting tool for engineers to a vehicle for business managers to fundamentally improve their businesses.

The “Software as a Service” model in service-oriented computing allows loosely coupled software components to be designed and integrated with other software systems. Web services, together with service-oriented architectures, are promising integration technology to facilitate legacy system Webification. However, since most components in a legacy system were not designed and developed as services, the current software systems need to be converted into a set of loosely coupled services. Therefore, a service-oriented software reengineering process is essential for legacy systems to survive in the service-oriented computing environment. In this service-oriented software reengineering process, understanding, decomposing and reusing legacy code turn to be important activities. In this thesis, a methodology for Service-Oriented Software Reengineering (SOSR) is proposed to support the identification, extraction and integration of reusable legacy code. According to both the result of legacy system assessment and a service-oriented analysis and design process, a reengineering decision is made by proposed rules. Based on the service-oriented software reengineering decision, ontologies for SOSR, which consists of Domain Concept Ontology (DCO), Functionality Ontology (FO) and Software Component Ontology (SCO), are developed by the ontology development methodologies. These ontologies store knowledge on both application domain and code entities, which support further legacy code analysis. The identification of service candidates in legacy systems is achieved by mapping FO and SCO via a novel method combining Formal Concept Analysis (FCA) and Relational Concept Analysis (RCA). After the service candidates are identified, the reusable legacy code is extracted by dependency analysis and program slicing. Some rules are defined in code query language for the detection of dead code. Program slicing techniques are applied as main reverse engineering techniques to recover executable legacy code. An Executable Union Slicing (EUS) algorithm is defined to generate executable legacy components with high cohesion and low coupling properties. In the integration phase, extracted legacy components with core legacy code can either be wrapped into Web services for the service orchestration in the business layer, or be composed in a software service provider. The proposed SOSR methodology is proved flexible and practical to migrate legacy applications to service-oriented architectures by the case studies. It can be customised according to different legacy systems. This methodology can help software developers and maintainers to reengineer the tightly coupled legacy information systems to the loosely coupled and agile information systems.

Scientific projects, businesses, and individual devices such as smart phones, tablets and embedded devices are collecting and retaining unparalleled and growing amounts of data. Initially, spatial locality of the data (collocation of data and application) cannot be assumed and local resource constraints impact monolithic legacy applications. Resource restrictions and less feasible approaches such as moving large data sets within these paradigms are not feasible for certain legacy applications. As such we have taken a renewed look at Remote Procedure Call mechanisms and designed, built and evaluated a RPC mechanism called Automated Legacy system Remote Procedure Call generator (ALRPC). ALRPC allows us to convert monolithic applications into distributed systems by selectively and semi-automatically moving individual functions to different process spaces. This improves spatial locality and resource constraints of critical functions in legacy applications. Empirical results from our initial experiments show that our mechanism’s level of automation outperforms existing industry strength tools and its performance is competitive within the scope of this work. / Graduate / 0984

Legacykod är något som är svårt för utvecklare att förhindra. Medan det finns mycket forskning kring att motarbeta legacykod och förnya legacysystem som använder utdaterade teknologier och designer, så har inte mycket fokus lagts på hur legacykod kan identifieras i sitt tidigaste skede. Hur dessutom definierar man legacykod? I denna studie så görs en litteraturstudie för att ta reda på vad för forskningsbakgrund det finns bakom legacykod i allmänhet. Därefter så utvecklas två prototyper i syfte att upptäcka mönster under utvecklingen som kan vara egenskaper till legacykod. I slutändan så utförs en enkät riktade åt mjukvaruutvecklare för att få insyn och tankar på vad legacykod betyder för dem och för att testa idéerna som togs fram från implementationerna. Den rekommenderade definitionen för legacykod är kod som inte har testats, ingen eller för lite dokumentation och är allmänt svår att förstå, vare sig med dokumentation eller utan. Observationerna från implementation av de två prototyperna bildade 7 riktlinjer som tar upp hur man kan identifiera uppväxten av legacykod. / Legacy code proves to be something difficult for developers to prevent. While much research exists to combat legacy code and renewing legacy systems that use outdated technologies and designs, not much focus has been put on how legacy code can be detected at its earliest stage. And how do you define legacy code? In this study, a literature review is done to find out the scientific background behind legacy code in general. Afterwards, two implementations of the same software are done to observe any events during the software development that can be characteristics of legacy code. In the end phase, a questionnaire-based survey is handed out to developers to get their insight and thoughts on what legacy code means to them and to test the ideas brought up from the implementations. A recommended definition for legacy code is code with no testing and little to no documentation and generally being hard to understand, whether with documentation or not. From the observations implementing the prototypes, 7 guidelines are formed to help identify and discover legacy code evolution.

Yes / Legacy systems have continued to pose a major challenge to digital transformation efforts in public administration. A comprehensive review of literature suggests seven levels of complexity in transforming legacy systems, including, being a stand-alone system, being part of a larger system, and data incompatibility, each depicting unique criteria and challenges. Nonetheless, very little is known as to what degree these complexities implicate the implementation of digital transformation efforts in public administration (PA). To address this gap, this research conducted an analysis on four cases of digital transformation in three European PA settings (i.e., Denmark, the Netherlands, and the UK). The findings revealed complexities that pose the key challenges to systems interoperability and integrability, which are crucial in any digital transformation project. In addition, a comprehensive understanding of the systems to be transformed, the policies which they are serving, and the broader PA setting in which they are implemented were deemed central to succeeding in digital transformation efforts.

Studien undersöker fenomenet migrering av legacy-system till molnlösningar. Ettlegacy-system är ett föråldrat IT-system som fortfarande använder äldre typer av teknikäven då mer modern teknik finns tillgängligt. Dessa system används vanligtvistillsammans med äldre affärssystem samt inom lager och produktionsmiljöer. Utifrån tidigare forskning på området identifierades det en lucka i litteraturen hursvenska konsultbolag inom IT-sektorn hanterar och genomför migreringar av legacysystem till molnlösningar. Denna undersökning tillämpade en kvalitativ intervjustudiemed semistrukturerad intervjuform och en tematisk analys genomfördes. Litteratursamlades även in kring tidigare dokumenterade utmaningar och metoder för att skapagrundläggande förståelse inom ämnet. Studien ämnade kartlägga vilka utmaningar, metoder och hantering av utmaningar IT konsulter möter i deras arbete. Denna studie identifierar totalt tre tillvägagångssätt förmigreringar, först en förstudie, sedan två olika metodval, Rehost och Replace. Vidareframförs även totalt nio olika utmaningar samt vilka tekniska åtgärder konsulter utför ihanteringen av dessa. Studien bidrar även med att öka antalet studier mot näringslivetgenom att djupare undersöka svenska konsulters arbete med migrering av legacysystem. / This study investigates the phenomenon legacy-system migration to cloud solutions.Legacy-systems are described as an outdated IT-system which still uses older types oftechnology even though more modern technology is available. These systems areusually found in older ERP-systems, as well as in warehouses and productionenvironments. Based on previous research in the field, a gap was identified in the literature on howSwedish consulting companies in the IT-sector handle and implement migrations oflegacy-systems to cloud solutions. This study applied a qualitative interview study withsemi-structured interview form and a thematic analysis was conducted. Literature wasalso collected around previously documented challenges and methods for creating basicunderstanding of the subject. The study aims to identify challenges, methods, and the management of challenges IT consultants face in their work. The study presents a total of three different methods,first a feasibility study on migration, then two different method choices, Rehost andReplace. Furthermore, a total of nine different challenges are presented, as well as whattechnical measures consultants perform in handling them. The study also contributes toincreasing the number of studies towards the industry by examining in more dept thework of Swedish consultants on the migration of legacy-systems.

A manutenção de sistemas legados tem se tornado uma preocupação constante das grandes empresas. O setor bancário brasileiro, por exemplo, possui milhões de linhas de código confeccionados em linguagens procedurais, essenciais para atingir os objetivos de negócios destas instituições. Muitos desses programas são considerados bem antigos, possuindo mais de 30 anos de existência e, apesar de serem extremamente úteis para estas organizações, não permitem aproveitar as vantagens das novas tecnologias, tais como o uso de interfaces gráficas, processamento distribuído, entre outros. Fazer um outro aplicativo de software a partir do início pode ser uma tarefa muito árdua e incorrer em grandes riscos para o negócio da empresa. Migrar esses sistemas aos poucos parece ser a melhor estratégia. Isso porque, a utilização dessa abordagem permite que a adaptação dos usuários ao novo sistema seja gradativa, ou seja, ocorre à medida que as funcionalidades de negócio são contempladas pelo novo sistema. Considerando a necessidade evidente que essa migração terá de ocorrer mais cedo ou mais tarde, este trabalho propõe um processo para permitir uma evolução gradual do software legado para uma plataforma mais moderna e de mais amplo uso atualmente, que possa atender melhor às novas necessidades dos negócios. Esse processo é formado por etapas de avaliação da situação atual do sistema, de transformação de arquitetura e de transformação do código funcional para o orientado a objetos. Além disso, é direcionado por indicadores de qualidade e apoiado por tipos de visão e respectivos estilos arquiteturais. O foco deste trabalho está em sistemas de instituições financeiras desenvolvidos em Mainframe ou AS/400, onde há grande incidência de códigos antigos orientados a procedimentos. / The maintenance of old legacies software has become a constant concern of the great companies. The Brazilian banking sector, for example, has millions of lines of code made under the functional paradigm, essential to reach the business-oriented objectives of these institutions. Many of these systems are very old, arriving to possess more than 30 years of existence. These programs, extremely useful for these organizations, do not allow the use of the advantages of the new technologies, such as the use of graphical interfaces, distributed processing and so on. The replacement of all old system for a new on may be a very arduous task and to incur into great risks for the company. Migrate these systems in small steps seems to a better strategy to deal with this problem that will have to be faced earlier or later. This work considers process to allow the gradual evolution of the legacy system to a better platform that allows the use of the advantages of the new technologies, through the use of quality indicators, the evaluation of the current system, the transformation of the architecture with focus at the change of functional paradigm to the object oriented one and of the use of view types and the corresponding architectural styles. This work is mainly delivered to financial institutions systems developed in Mainframe or AS/400 that have great incidence of these old legacies systems.