1. DPS in Computing CSIS Pace University An Integrated Decision Model for Replacing or Extending the Life of Legacy Systems by David Fronckowiak November 22, 2008

2. Agenda Definition of Legacy Original Research Problem Data Collection Legacy System Modernization / TAM Modified Research Problem Research Challenges Research Methodology Interview / survey questions

3. Definition of Legacy Systems A system “developed sometime in the past which is critical to the business in which the system operates.” (1) “Large software systems that we don’t know how to cope with, but that are vital to our organization.” (2) A legacy system is defined as “any information system that significantly resists modification and evolution to meet new and constantly changing business requirements.” (3) “Critical software that cannot be modified efficiently.” (4) “Any production-enabled system regardless of language or platform is a legacy system.” (5) Define legacy systems “as systems that are not protected with a suite of tests. A corollary to this is that you are building legacy code every time you build software without associated tests.” (6) Proposed Definition: Systems are considered legacy if any of their components, such as the operating system, utilities/libraries, and applications, are out of technical support or the system cannot be modified to meet all changing business requirements, but the system is still useful.

4. Legacy System Criteria CharacteristicLegacy SystemNon-Legacy System Operating SystemNon-supportedSupported HardwareDoes not support supported versions of the OS, DB, or programming language Supports all application dependencies Application Language(s) Availability of Support SkillsLowHigh Maintenance CostLow - High Business functionalityMeets business functionality, but difficult to extend Meets business functionality and allows for extension Business logic and code separated NoYes

5. Legacy System Modernization Legacy system modernization efforts fail for the following reasons: Complexity Many interfaces There are many modernization options Software technology and engineering processes Software technology and business requirements Risk management Commercial components Business process / objectives defined

6. Research Problem Evolution  Original research problems:  During the decision process to extend the life of a legacy system or replace the legacy system, what key factors must be considered?  Are the factors industry dependent?  How is the decision to replace or extend the life of a legacy system derived?  One champion or review board?  What technologies are the most frequently used and the most amenable to extending the life of legacy systems?

7. Data Collection - Banking

8. Data Collection -Insurance

9. Framework - Banking Functional Business needs 197019751985198020052010199020001995 MVS/CICS/ COBOL Mainframe IP Network (1990 Freddie Mac) Web Interface (1997 Citibank) Wrapping with a Corba Interface (1999 Credit Suisse) MISMO XML Stds. (2000) SOA Virtualization

10. Modified Technology Acceptance Model (TAM) Intention to Design Perceived Usefulness Perceived Ease of Use Usage Behavior Task-Technology Fit - Web Services - Virtualization - COTS - Component Design Extend Replace Do nothing Legal Maint / Support Customer access / usability Operations Cost Risk Benchmarking Sat / Performance Metrics User Mobility

11. Cautions Data collection as compared to research Data sources, i.e., banking and insurance Dependencies

12. Research Problem Evolution Modified research problems: What are the legacy system management decision factors which influence the acceptance of newer technologies in legacy system management? In managing legacy systems, if a legacy subsystem is enhanced, was this subsystem evaluated in the context of the entire legacy system? (Note: Deming and LEAN advocate optimizing the whole system.) If not, why was the entire system not analyzed for modification?

13. Legacy System Management Complexity System X Subsystem 1 Decision-making process based on the reference life-cycle model: Simplification Ordinary reactive and preventive maintenance Extraordinary adaptive maintenance Replacement Hardware Firmware OS Middleware Application DB Maintain/extend through: (1) APARS (2) TL (3) CSD’s (4) Patches Subsystem 2 Subsystem N G. Canfora and A. Cimitile, “A reference life-cycle for legacy systems,” Workshop on Migration Strategies for Legacy Systems, Boston, Ma., May 1997.

14. Complexity in the Replacement Decision Implementation Characteristics Mfg. EquipmentLegacy System SpeedThruputResponse time AvailabilityEquipment uptimeSystem uptime ScheduleOrder, on-dock delivery, setup, qualify Variable InterfacesPower Material handling Chemicals / exhaust Other systems – DB mapping FlexibilityLow - High ComponentsHighly complexLow – High with respect to architecture WarrantyYesCOT S/W – Yes Interfaces - No

15. Research Challenges  Four large bodies of literature:  Legacy Systems  Decision making theory / models  Systems analysis (Overall system as compared to component parts)  Technology  Research methodology:  Survey, interview, case study  Validity -> Instrument measures what it is actually intended to measure.  Sample size  Sample scope Yen-tsai Wang, “Information Technology Investment Decisions and Evaluation in Large Australian Companies,” Griffith University Dissertation, Australia, May 2006. 1) Analysis and Planning 2) Evaluation of cost and benefit 3) Project selection and implementation 4) Post implementation evaluation

16. Interview / Survey Questions Question generation (Survey questions will use a Lickert scale) Section 1 – Demographics Industry Company size Definition of a legacy system Section 2 – Intelligence: Why is a decision needed to modify a legacy system? Customer Access / functionality Need web access Legal Financial reporting including security Maintenance and Support Skill base Section 3 – Design: Factors considered in the design phase with potential alternatives Satisfaction and performance metrics Were quantifiable metrics used to determine performance and satisfaction COTS Were off-the-shelf applications analyzed or prototyped? Virtualization Was virtualization considered in legacy system migration? Mobility Was customer mobility addressed, i.e., web, phone, PDA, etc.? Component redesign Were tools used to surgically dissect the application to determine those components whose lifetime can be extended or replaced? RISK / Schedule How was risk addressed? Section 4 – Choice: Elements in the decision process If a subsystem was enhanced, was this subsystem reviewed in light of the overall system? If not, why? (cost, schedule, resources, available technology, risk, business strategy)

17. Backup

18. Sector Architect comments: Legacy System wrap and replace methodology Compared to microsurgery Steps in the microsurgery: Scan the current environment Drill down into the components Isolate and understand the dependencies Develop contracts between the service provider and the service consumer Cut and replace Always have SOA in mind Focus on the differences between the banking and insurance industries: Banking sites visited frequently Insurance carrier site visited less frequently Many of the legacy extension techniques utilized may depend upon the format of the backend legacy system and the database structures (IMS, DB2, Oracle, …) which will dictate different interface technologies.

19. Observations Companies are looking at improving customer access of banking / insurance products, not pure legacy system extension Legacy system extension methods do differ by country Eastern European and Asian countries with minimal infrastructure are leap-frogging Western countries The banking industry must comply with federal regulations which stimulates business process and mainframe change (Check 21 and Patriot Acts) Each company within the banking and insurance industries faces unique challenges Numerous vendors supply application solutions for legacy system extension and internet presence From the data, the insurance industry is lagging the banking industry in terms of addressing legacy system concerns and an internet presence. Legacy System wrap and replace methodology: Compared to microsurgery Steps in the microsurgery: Scan the current environment Drill down into the components Isolate and understand the dependencies Develop contracts between the service provider and the service consumer Cut and replace Always have SOA in mind

20. References 1)Ransom, J., I. Sommerville, and I. Warren, A Method for Assessing Legacy Systems for Evolution. IEEE. 2)Bennett, K.H., M. Ramage, and M. Munro, Decision Model for Legacy Systems. IEEE Proceedings Software. 146(3): p. 153- 159. 3)Brodie, M.L. and M. Stomebraker, Migrating Legacy Systems. Burlington, MA.: Morgan Kaufmann Publishers, 1995. 4)Gold, N., The Meaning of Legacy Systems, in SABA Project Report: PR-SABA-01, version 1.1: University of Durham. 5)Ullrich, William, “Breathing New Life into Legacy Systems,” www.sdtimes.com/article/story_20031015_09.html, Oct. 15, 2003. www.sdtimes.com/article/story_20031015_09.html 6)Poppendieck, Mary and Tom, Implementing Lean Software Development: From Concept to Cash. Boston, MA.: The Addison-Wesley Signature Series, 2007.