The Ghosts of Legacy SOftware
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Transcript of The Ghosts of Legacy SOftware
‹#› Hetbegintmeteenidee
THEGHOSTSOFLEGACYSOFTWARE
ILLUSTRATION:CharlesDickens:AChristmasCarol.InProse.BeingaGhostStoryofChristmas.WithIllustraMonsbyJohnLeech.London:Chapman&Hall,1843.FirstediMon.
@patricia_lago
‹#› Hetbegintmeteenidee
Legacy software doesn’t exist anymore – we just haven’t noticed
PHOTO:NIGELPARRY
PATRICIALAGO©2016
‹#› Hetbegintmeteenidee
Are we looking at the right problems?
DorianGray(2009),themoMonpicture
PATRICIALAGO©2016
PATRICIALAGO©2016
ENIAC Programmers Project (1946) Photo: Corbis
MicrosoB (2016) experimenGng with underwater DC to beat the heat
(?)
Legacy of the past, present, and future
PATRICIALAGO©2016
Approaches to modernize the “legacy of the past”: activities
Academic: Arch-shaped approaches
Industrial: Bowl-shaped approaches
TransformaGon
Forward engineering Reverse engineering
IdenGfy target
Forward engineering
Reuse legacy
PATRICIALAGO©2016
Approaches to modernize the “legacy of the past”: knowledge conversions Industrial only
Insights from legacy
Map soluGons based on experience
Convert legacy architecture/design into to-be business processes
PATRICIALAGO©2016
Legacy of the present: create new value from pre-existing systems
• Cloudenvironment
• HosMng
• Keys:• Cloudservicemodel(IaaS,PaaS,SaaS)• MigraMongranularity(full,parMal)
• Seamless• UnnoMceabletocustomers• DrivenbyobjecMvecriteria(incl.risksandbenefits)
A. Efremovska & P. Lago, From Legacy to Cloud: Risks and Benefits in SoBware Cloud MigraGon, 2016 (under submission)
PATRICIALAGO©2016
Legacy of the future: It’s all about longevity, seamless change, flexibility
• Context-dependent• Dealwithcomplexity(*)
(*) K. Dorst, Frame InnovaGon, MIT Press (2015)
OPEN (degrees of visibility)
DYNAMIC (conGnuous change)
COMPLEX (shared benefits and responsibiliGes)
NETWORKED (mulGple stakeholders)
Legacy of the future: Cyber-foraging optimizes functionality by resource discovery
Resource scarce environment
MissionimpossibleII(2000),themoMonpicture
Smart home
Legacy of the future: ARCHITECTURAL TACTICS FOR CYBER-FORAGING
G. Lewis & P. Lago, “Architectural TacGcs for Cyber-Foraging”, Journal of Systems and SoBware, Elsevier (2014)
Legacy of the future: DETECT context and usage
G. Lewis & P. Lago, “CharacterizaGon of Cyber-Foraging Usage Contexts”, In SoBware Architecture, Springer LNCS (2015)
Legacy of the future: DETECT context and usage
G. Lewis & P. Lago, “CharacterizaGon of Cyber-Foraging Usage Contexts”, In SoBware Architecture, Springer LNCS (2015)
Legacy of the future: QUALITY-DRIVEN INTELLIGENCE
Determine favorable condiGons (low bajery, presence surrogate, connecGvity)
• Save bajery, decrease network communicaGon
• Faster response Gme than local execuGon
• Greater compuGng power in the surrogates
• Decide on intermediate data caches
• OpGmize network bandwidth
PATRICIALAGO©2016
PAST ProblemaGc systems with business value Port to new technological landscapes
Past, present, and future From LEGACY SOFTWARE to SOFTWARE LEGACY
FUTURE InnovaGon Create intelligent systems that are flexible, long-lived, and change seamlessly
PRESENT IntegraGon Create new value from pre-exisGng systems
The challenges from industry are others: agile refactoring, quality over funcGonality, context adaptaGon, knowledge management, business sustainability, societal impact