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Compaq Enterprise Technical Symposium 2001 Application Migration Necessity, Concepts, and Techniques Brian Hetrick SAIE (Systems Application Integration.

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Presentation on theme: "Compaq Enterprise Technical Symposium 2001 Application Migration Necessity, Concepts, and Techniques Brian Hetrick SAIE (Systems Application Integration."— Presentation transcript:

1 Compaq Enterprise Technical Symposium 2001 Application Migration Necessity, Concepts, and Techniques Brian Hetrick SAIE (Systems Application Integration Engineering) Compaq IQ Center

2 2 SAIE/IQC New England  Software development/ migration in Nashua NH, co-located with and cooperating with BCSG Software Engineering  Performance facility in Littleton MA  Develop integrated applications / solutions for vertical markets  Address customer solution needs for: –Migration –Supply chain integration –Customer relations management –Business intelligence –Zero Latency Enterprise systems

3 3 AgendaAgenda  Why Migrate?  Application Development  Migration Types and Techniques  Reengineering = Development  Migration Costing  Migration Process

4 4 Why Migrate?

5 5 Platform Lifetimes

6 6 Application Development

7 7 Financial Models  Manufacturing Model –Set all of good, fast, cheap  Engineering Model –Set two of good, fast, cheap –Third can be estimated  Research Model –Set two of good, fast, cheap –No idea of third

8 8 Development Behavior Rewarded is Development Behavior Obtained Time to Complete Program Size Data Space Size Program Clarity UI Friendliness TimeSizeDataClearUI Team Goal Team Rating For

9 9 Development Cost Depends on Schedule

10 10 Budget-Driven Development...  Cost and duration are easy to measure, so often become driving metrics.  In the three-way trade-off, “good, fast, cheap: pick two,” fast and cheap get picked.  For minimum time, project cost should triple; but flat budget means two-thirds of the work is not done.

11 11 … Sacrifices “Invisible” Deliverables  Under pressure, parts of project are sacrificed  Pieces sacrificed are “invisible” –Reliability –Maintainability –Documentation –Adaptability –Performance

12 12 Applications Are Liabilities, Not Assets  Maintenance costs are % of total lifetime costs  Every application is an expense stream incurred but not yet paid  Development actions determine expense of maintenance

13 13 Why Migration Can Be Expensive  If people built houses the way they write computer programs, the first woodpecker to come along would destroy civilization — Dijkstra  We do not know what a software “safety factor” is  We build environment- specific software

14 14 Transient Components  Migration “scaffolding” or “bridges” may be needed, later removed  Tools may need to be invented or adapted to the unique needs of the migration  While “non-deliverable” or “disposable,” these are essential

15 15 Migration Types and Techniques

16 16 Migration Scope and Stages  Migration happens to a business system, not just an application  Application, platform, operations, environment, business process, work flow, documentation, users all interact  Changes must be: –coordinated to avoid pain –rate limited to avoid chaos

17 17 Migration Types  Re-implementation: move application “as is” to new platform  Re-architecting: move application and exploit properties of new platform  Re-engineering: rethink business processes, work flow, and application

18 18 Re-ImplementationRe-Implementation  Source application on target platform  No functional changes

19 19 Rezitigamed Renaelc DaehKcartE OK Re-ArchitectingRe-Architecting  Source function on target platform  Changes to exploit platform

20 20 Re-EngineeringRe-Engineering  New architecture, functions to support new processes

21 21 Migration Techniques  Platform Emulation: emulate original hardware  O/S Emulation: emulate original operating system  Idiom Translation: change idioms to that of new platform  Adaptation Layer: extract “kernel” application, add interface to new platform

22 22 “Big Bang” or Stepwise Migration  Migrating an application is like getting to the top of a cliff  There is always a direct, high- energy, high-risk route  There are usually several roundabout, low-energy, low- risk routes  Direct path is not always quicker or cheaper

23 23 Risk Minimization  Minimize risk: change one factor at a time  “Platform” is just one factor  Other factors: –database –network and IPC methods –transaction manager –object manager –etc.

24 24 Sequence Planning  Theoretically, a combinatorial non-linear optimization problem  Practically, finding a path through alternatives where information is difficult to obtain

25 25 Acquire Hardware Migrate Software Test Deploy Acquire Hardware Migrate Software Test Deploy Update Emulation as a Sequencing Aid  Emulation permits reordering the initial deployment and migration  Can deploy, then migrate

26 26 Architectural Preparation  On source platform, parameterize system and third-party dependencies  Recreate implementation of system and third-party dependencies for new system, third-party products  Easily move “kernel” application to new environment Hardware TPSD/BO/S Application Adapter D/B Adapter TPS Adapter Hardware O/S Adapter

27 27 Major Migration Cost Drivers  Application Size  Type of Migration  Concurrent Migration and Development  Informal Development –No current sources –No build procedures –No test procedures  Parochialism –Application designed for source platform –Application micro- optimized for source platform –Language dialects

28 28 Reengineering = Development

29 29 Recast as Client/Server Validate D/B Update ReportCheck Validate D/B Update Report Check

30 30 Security Audit/Upgrade Observe Consume Impersonate Subvert Destroy

31 31 Migration Costing

32 32 Application Migration Predictability  “Estimated Delivery Date (EDD): the earliest time for which we cannot prove we will not be finished” does not work Predicted “ Problems ” $  Some migration costs are predictable  Some are unpredictable, and might be large

33 33 Predictable Migration Costs  Measurable properties: –Application size –Language standard conformance –System dependencies at expression level –Module cohesion  Measure with: –Diagnostic compilers –Specialized tools

34 34 Unpredictable Migration Costs  Unmeasurable properties: –System dependencies at architectural level –Quality of interface abstraction layers –Resilience to changes in environment  Identify factors by: –Manual inspection –Subsystem sample migration

35 35 Rules of Thumb  Abstraction is good  Use major new technologies where applicable  The best code is the code that is not there  Migration costs 3-10% of redevelopment

36 36 Statistical Correlations  Richard Bellman: the use of statistics is a measure of our ignorance, not our knowledge  But it is better than nothing

37 37 IQC NE Discoveries  Currently being written up for submission to IEEE Transactions on Software Engineering or JACM TUIT, round, quantity 1

38 38 Estimate of Unpredictable Problems  Multifactor cost model gives estimates of cost of unpredictable problems within factor of 2  Bulk estimates can be refined through detailed analysis of stratified sample of code $

39 39 Compaq Upgrade/Migration Services  Services local through PS or remote through IQC: –Turnkey migration –Co-development migration –Project management  Remote through IQC NE: –Architectural assistance –Oracular assistance retainer (question line)

40 40 Migration Process

41 41 Migration Process Overview Migration Workshop Migration Assessment Application/System Migration Test Deploy Migration Conference Call Contact Compaq

42 42 Preparing for Migration  Change = disruption = risk  Lessen risk by migrating in stages or steps  Each stage proves concepts and provides process  Small changes to avoid chaos  The system supports the business at all stages of the process

43 43 Requirements and Goals  Business –Business functions and processes –When migration must be complete –Maximum migration investment and expense  Environment –Operating systems –Third party products –Other applications –External interfaces

44 44 Preparation Strategy  Identify: –critical functions –type, technique, phasing –in-house expertise –timeframe, budget, and resources –application environment –related business process –supporting batch processes

45 45 Identify Migration Techniques  Find which technique is best suited for this migration  Affects immediate investment and risks, long-term costs, and the next migration

46 46 Plan Risk Management  Risk identification  Risk evasion tactics  Event detection triggers –Process metrics  Event recovery

47


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