Upload
joseph-franklin
View
221
Download
0
Tags:
Embed Size (px)
Citation preview
YOU WILL ANYHOW
CHAPTER 11
Plan To Throw One Away
Pilot Plant
Three phases of plant production Design Plant Pilot Plant Production Plant
Throwaway System
Failed concept in system programmingOn schedule delivery often means the first
thing builtBarely useableOften follow-up systems are neededQuestion: Build a throwaway system in
advance or deliver it to the customer?
Results of Implementing a Throwaway
Buys builders timeAgony for customersDistraction for builders by customersBad reputation for product and builders
Throwing away the Throwaway
Giving the throwaway to the customer
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.
Plan the System for Change
ModularizationExtensive subroutinesPrecise and complete definition of interfacesAll with complete documentationSelf-documenting in high-level languages
reduces errorsCompile-time operations to include standard
declerations
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
Two Steps Forward One Step Back
Maintenance costs are usually 40% more than development costs
The more users the more bugs are foundFixing a defect has a high chance to cause anotherRegression Testing takes previous battery of tests
and tests them against the new version of the system
Hence the importance of addressing problems early
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
Conclusion
BETA