Poka-yoke in software A software products company sells application software to an international market. The pull-down menus and associated mnemonics provided with each application must reflect the local language. For example, the English language menu item for “Close” has the mnemonic “C” associated with it. When the application is sold to Urdu speaking users, the same menu item is “Band Karen” with mnemonic ”ب”. To implement the appropriate menu entry for each locale, a “localizer” translates the menus accordingly. The problem is to ensure that each menu entry conforms to appropriate standards and there are no conflicts, regardless of the language used.

Software Engineering II Lecture 32 Fakhar Lodhi

Recap

Mistake-proofing menu mnemonics Prevention device –Write a program to generate mnemonics automatically, given a list of labels in each menu. –Would prevent mistakes, but the problem of choosing a good mnemonic is difficult and the effort required would not be justified by the benefit gained.

Mistake-proofing menu mnemonics Prevention device –Write a program to prevent the localizer from choosing mnemonics that did not meet the criteria –Would prevent mistakes –Benefit is minimal; incorrect mnemonics are easy enough to detect and correct after they occur

Mistake-proofing menu mnemonics Detection device –Write a program to verify that the chosen menu labels and mnemonics meet the criteria. –We run this program to detect errors –Send it back to localizer –Back and forth

Mistake-proofing menu mnemonics Detection device –Write a program to verify that the chosen menu labels and mnemonics meet the criteria. –The localizer would run this program to detect errors –Would give quick feedback

KEY PROCESS AREAS (KPAs) As Defined by SOFTWARE ENGINEERING INSTITUTE (SEI) “SOFTWARE ENGINEERING AND MANAGEMENT PRACTICES” REQUIREMENT S MANAGEMENT PROJECT PLANNING PROJECT TRACKING & OVERSIGHT SUBCONTRACT MANAGEMENT SOFTWARE QUALITY ASSURANCE SOFTWARE CONFIGURATION MANAGEMENT LEVEL 2 -REPEATABLE LEVEL 1 - INITIAL

The “First Law” of Change No matter where you are in the system life cycle, the system will change, and the desire to change it will persist throughout the life cycle. Bersoff, et al, 1980

SCM - CMM Purpose To establish and maintain the integrity of software products through out the project’s life cycle.

Software in the 21st Century More complex software projects –Size, sophistication, technology –Millions of users –Multilingual –Multi-platform support (hardware, software) –Distributed environment –Configurations – desktop, standard, professional, enterprise –Brutal competition –Maintenance frequency – corrective and adaptive?

More complex development environment with shorter reaction time, results in confusion and chaos!

Change Chaos Problems of identification and tracking: –“This program worked yesterday. What happened?” –“I fixed this error last week. Why is it back?” –“Where are all my changes from last week?” –“This seems like an obvious fix. Has it been tried before?” –“Who is responsible for this change?”

Change Chaos Problems of version selection –“Has everything been compiled? Tested?” –“How do I configure for test, with my updates and no others?” –“How do I exclude this incomplete/faulty change?” –“I can’t reproduce the error in this copy!” –“Exactly which fixes went into this configuration?” –Nobody knows which versions of programs are final Where is the latest version? Which version is the right one? I have so many I have lost my latest changes –Latest versions of code overwritten by old versions –There was a minor problem, I fixed it but it is no longer working I can’t figure-out the changes made to the previous version. I can’t go back

More Chaos …. Design document out of sync with programs I don’t know if all the changes that were suggested have been incorporated Which code was sent to testing? Software Delivery Problems –“Which configuration does this customer have?” –“Did we deliver a consistent configuration?” –“Did the customer modify the code?” –“Did the customer skipped the previous two releases. What happens if we send him the new one?” –Shipped the wrong version to the client.

Configuration management is concerned with managing evolving software systems –System change is a team activity –CM aims to control the costs and effort involved in making changes to a system Involves the development and application of procedures and standards to manage an evolving software product Part of a more general quality management process When released to CM, software systems are called baselines and serve as the starting point for further development Configuration management