Presentation is loading. Please wait.

Presentation is loading. Please wait.

1 Lecture #5 “No scene from prehistory is quite so vivid as that of the mortal struggles of great beasts in the tar pits. Large system programming has.

Similar presentations


Presentation on theme: "1 Lecture #5 “No scene from prehistory is quite so vivid as that of the mortal struggles of great beasts in the tar pits. Large system programming has."— Presentation transcript:

1 1 Lecture #5 “No scene from prehistory is quite so vivid as that of the mortal struggles of great beasts in the tar pits. Large system programming has over the past decade been such a tar pit, and many great and powerful beasts have thrashed violently in it.” Fred Brooks, 1975 Copyright 2000 by USC and the Center for Software Engineering, all rights reserved.

2 2 Lecture #5 “Everyone seems to have been surprised by the stickiness of the problem, and it is hard to discern the nature of it. But we must try to understand it if we are to solve it.” Fred Brooks, 1975

3 3 Lecture #5 Understanding the Tar Pit: Model Clashes Model (Webster): A description or analogy used to help visualize or analyze something; a pattern of something to be made –Includes product models, process models, property models, success models Model Clash: An incompatibility among the underlying assumptions of a set of models –Produces conflicts, confusion, mistrust, frustration, rework, throwaway systems Model Integration: Choosing and/or reengineering models to reconcile their underlying assumptions.

4 4 Lecture #5 Examples of Model Clashes Product Model Clashes: structure clashes, traceability clashes, architectural style clashes COTS-driven product and Waterfall process Risk-based process and spec-based progress payments Design-to-cost process and tightly-coupled architecture Incremental process and Rayleigh-curve staffing model Evolutionary development without life-cycle architecture Golden Rule and stakeholder win-win Spec-based process and IKIWISI success model –I’ll know it when I see it

5 5 Lecture #5 Classic Model Clashes In Practice Model Clashes and Tar Pits: Bank of America Master Net Example Master Net Stakeholders Master Net Contract Initial Progress The Tar Pit The Bottom Line Contributing Model Clashes R.Glass, Software Runaways, Prentice Hall, 1998, PP

6 6 Lecture #5 Reconciling Model Clashes Use stakeholders’ success models, domain models to drive choices of other models –MBASE conceptual framework –Example: Process model decision table Reconcile underlying assumptions –Example model clash patterns Pre-package domain-integrated models –Successful examples

7 7 Lecture #5 Where’s It All Going? UML CORBA COM Architectures Product Lines OO Analysis & Design Domain Ontologies COTS GOTS COCOMO COCOTS Checkpoint System Dynamics Metrics - ilities Simulation and Modeling Win-Win Business Case Analysis Software Warranties QFD 10X Six Sigma Award Fees JAD RAD Spiral Waterfall Risk Management Business Process Reengineering CMM’s Peopleware IPT’s Objectory Groupware

8 8 Lecture #5 One View: Models Needing Integration MBASE Success Models Product Models Property Models Process Models Win-Win Business Case Analysis Software Warranties QFD 10X Six Sigma Award Fees JAD RAD Spiral Waterfall Risk Management Business Process Reengineering CMM’s Peopleware IPT’s Objectory Groupware UML CORBA COM Architectures Product Lines OO Analysis & Design Domain Ontologies COTS GOTS COCOMO COCOTS Checkpoint System Dynamics Metrics - ilities Simulation and Modeling

9 9 Lecture #5 MBASE Integration Framework

10 10 Lecture #5 MBASE Conceptual Framework

11 11 Lecture #5 MBASE Conceptual Framework

12 12 Lecture #5 MBASE Model Integration: LCO Stage Domain Model WinWin Taxonomy Basic Concept of Operation Frequent Risks Stakeholders, Primary win conditions WinWin Negotiation Model IKIWISI Model, Prototypes, Properties Models Environment Models WinWin Agreements Viable Architecture Options Updated Concept of Operation Life Cycle Plan elements Outstanding LCO risks Requirements Description LCO Rationale Life Cycle Objectives (LCO) Package Anchor Point Model determines identifies determines serves as table of contents for situatesexercise focus use of focus use of determines guides determination of validate inputs for provides initializeadoptidentify update achieveiterate to feasibility, consistency determines exit criteria for determines content of validates readiness of initializesinitializes

13 13 Lecture #5 Clashes Among MBASE Models

14 14 Lecture #5 MBASE Model Clashes

15 15 Lecture #5 Success Models Drive Other Model Choices Success Model Key Stake- holders Key Property Models Process Model Product Model Demo agent-based E- commerce system at COMDEX in 9 months Entrepreneurs, venture capitalists, customers Schedule estimation Design-to-schedule Domain constrained by schedule; architected for ease in dropping features to meet schedule Safe air traffic control system Controllers, Govt. agencies, developers Safety models Initial spiral to risk-manage COTS, etc.; Final waterfall to verify safety provisions Architected for fault tolerance, ease of safety verification

16 16 Lecture #5 MBASE Deliverables General Considerations Operation Concept Description (OCD) System and Software Requirements Definition (SSRD) System and Software Architecture Description (SSAD) Life Cycle Plan (LCP) Feasibility Rationale Description (FRD)

17 17 Lecture #5 Class Milestones September 20 All teams formed October 4-8 WinWin Client Negotiation Results; Initial Prototype October 14 LCO Drafts on Web Site October LCO Package Architecture Review Boards October 22 LCO Package Due November 19 LCA Drafts on Web Site November LCA Package Architecture Review Boards November 29 LCA Package Due; Construction well underway; Testing and Debugging commence December 10 IOC Drafts on Web Site December 13 IOC Packages Due, Individual Critiques Due Finals Week December Product Demos December

18 18 Lecture #5 Life Cycle Anchor Points Life Cycle Objectives (LCO) Like getting engaged Life Cycle Architecture (LCA) Like getting married Initial Operational Capability (IOC) Like having your first child Major Milestones InceptionElaborationConstructionTransition Iteration 1Iteration 2Iteration 3Iteration 4Iteration 7Iteration 5Iteration 6 LCO LCAIOC Full Release

19 19 Lecture #5 Project Results Time (months) Progress (% coded) Conventional Late Design Breakage Iterative Development LCO Final Qual Test Integration Begins Continuous Integration LCA IOC

20 20 Lecture #5 MBASE WinWin Spiral

21 21 Lecture #5 Where Are We Now? Overview of MBASE Operation Concept Description (OCD) System and Software Requirements Definition (SSRD) System and Software Architecture Description (SSAD) Life Cycle Plan (LCP) Feasibility Rationale Description (FRD)

22 22 Lecture #5 MBASE Invariants and Variants

23 23 Lecture #5 MBASE Guidelines MBASE Model Guide –describes models –describes suggested model creation approach (variant) MBASE Process Guide –Describes activities and dynamic model integration large, so provided in EPG redundant with model guide (at present) MBASE Active Templates Active Templates Process Guide Model Guide “The Trinity”

24 24 Lecture #5 MBASE Model Guidelines

25 25 Lecture #5 MBASE Process Guidelines

26 26 Lecture #5 MBASE Active Templates

27 27 Lecture #5 General MBASE Considerations Made up of OCD, SSRD, SSAD, LCP, and FRD and various IOC plans Collaboration Essential, Elements Strongly Integrated –this reduces risk overall Keep deliverables in sync, strong interdependencies Conceptual integrity critical! Be consistent, traceable,… LCO: less structure, detail, more “vision” - major issues LCA: no “TBD”s, formal, no unresolved issues IOC: only detail what was actually built Generally no set number of pages –be concise, but cover, “lean and mean” –be willing to “throw away” –meet completion or “exit” criteria

28 28 Lecture #5 General MBASE Considerations Cont. Avoid repetition, instead reference the information. Avoid “broken” or “blind” or “vague” references Do not include text from guidelines, without relating to your project Follow formatting guidelines (grader win-condition!) –Describe what things are for your project, not the guidelines –Outline and summarize, avoid “the great system novel” –Use a consistent referencing format (e.g , REQ-7) Not “one size fits all” - tailor to your project, use only what is relevant –risk driven documentation IOC guidelines separated from LCO/LCA –there are places that they integrate and mix –look out for “construction phase”

29 29 Lecture #5 Operations Model Object Model Capability Requirements System Definition Class Model Project Requirements Statement of Purpose Project Goals Organization Goals System Capabilities Component Model Organization Entities Behavior Model Activity Model Enterprise model Domain DescriptionSystem AnalysisSystem Requirements Operational Concept Description (OCD) System and Software Requirements Definition (SSRD) System and Software Architecture Description (SSAD) Organization Background Organization Activities Interaction Model Levels of Service Levels of Service Requirements Integration of MBASE System Definition Elements System Design

30 30 Lecture #5 Modeling versus Documenting MBASE describes models, how to build them, and ways to communicate them. Documentation is a necessary consequence of modeling –why? –Also, the act of writing something down helps you solidify a model Communication is an essential part of the collaborative development approach Avoid documenting for documentation sake! –Everything you document should be the result of modeling –everything you document should have value and meaning to stakeholders (think about risk here) The documentation are the models!!! The Models are the documentation!!!


Download ppt "1 Lecture #5 “No scene from prehistory is quite so vivid as that of the mortal struggles of great beasts in the tar pits. Large system programming has."

Similar presentations


Ads by Google