1. YOU WILL ANYHOW CHAPTER 11 Plan To Throw One Away

2. Pilot Plant Three phases of plant production  Design Plant  Pilot Plant  Production Plant

3. Throwaway System Failed concept in system programming On schedule delivery often means the first thing built Barely useable Often follow-up systems are needed Question: Build a throwaway system in advance or deliver it to the customer?

4. Results of Implementing a Throwaway Buys builders time Agony for customers Distraction for builders by customers Bad reputation for product and builders Throwing away the Throwaway Giving the throwaway to the customer

5. The Only Constancy is Change Delivers satisfaction of a users needs rather than any tangible product. And that the users perception of that need will change as programs are built and used. Product change is inevitable. The programmer must be prepared for it rather than assuming it won’t happen.

6. Plan the System for Change Modularization Extensive subroutines Precise and complete definition of interfaces All with complete documentation Self-documenting in high-level languages reduces errors Compile-time operations to include standard declerations

7. Plan the Organization for Change Broader job assignments to make workers more flexible Large projects need multiple lead programmers under the manager The boss must keep his managers flexible as their talents allow Workers should be able to temporarily handle the workload for anyone in the project both up and down the ladder

8. Two Steps Forward One Step Back Maintenance costs are usually 40% more than development costs The more users the more bugs are found Fixing a defect has a high chance to cause another Regression Testing takes previous battery of tests and tests them against the new version of the system Hence the importance of addressing problems early

9. One Step Forward One Step Back With large systems: as the number of fixes increase there will eventually be a point were these fixes will not gain any ground and new problems will arise from them The system while technically still useable has worn out and an entirely new system needs to take over

10. Conclusion BETA