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Non functional requirements

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Pavel Růžička
Pavel Růžička

Knowing of non-functional requirements helps you to avoid of customers say „You should thing better!“.

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Non Functional Requirements 21.5.2010 - Pavel Růžička Product Development Department
Knowing of non-functional requirements Helps to avoid of customers say „Y o u s h o u l d t h in g b e t t e r !“ 2 21.5.2010 - Pavel Růžička Product Development Department
I t helps a lot if you know what is the “most critical“ non-functional requirement because this can dominate the best choice of development technique and internal design. 3 21.5.2010 - Pavel Růžička Product Development Department
4 21.5.2010 - Pavel Růžička Product Development Department
Non-functional requirements are aspects • Users have implicit expectations about how well the software will work. • These characteristics include • how easy the software is to use, • how quickly it executes, • how reliable it is, • and how well it behaves when unexpected conditions arise. • The non-functional requirements define these aspects about the system. 5 21.5.2010 - Pavel Růžička Product Development Department
Non Fuctional Requirements - General • Security • Exception Handling • Validation • Logging • Tracing / Testing • Monitoring / Reliability • Transaction • Storage • GUI Binding • Configuration 6 21.5.2010 - Pavel Růžička Product Development Department
Non Fuctional Requirements– System / Dev • Naming conventions • Caching, Performance • Scalability • RAM usage • Thread Sync 7 21.5.2010 - Pavel Růžička Product Development Department
Non Fuctional Requirements - Business • Time to market • Cost • Speed / Performance • Interoperability • Flexibility • Disaster recovery • Usability • Accessibility 8 21.5.2010 - Pavel Růžička Product Development Department
How to fetch non-functional requirements? • A n t i- s t o r ie s are things the user does not want to happen, commonly for safety or security reasons. • N o way we let an I L OV E Y OU E M ail worm in our System! • U s e a c h e c k lis t  9 21.5.2010 - Pavel Růžička Product Development Department
Security - Should access to be limited? - Is an access list necessary? - Access Control List - White List - Black List 10 21.5.2010 - Pavel Růžička Product Development Department
Exception handling - What errors can occur on runtime? - What it should do in case of error? 11 21.5.2010 - Pavel Růžička Product Development Department
Validation • Which input items are required? • Which of them need to be validated? • What to do if input is invalid? • How to recognize if an item is valid? (email, personal number, ZIP code...) Be aware - customer tends to change it frequently! 12 21.5.2010 - Pavel Růžička Product Development Department
Logging • It is about loggin from the user perspective, not developer’s logging • Which events should be logged? • Which items should log contain? • Is the last operation enough or you need history? • How deep the history should be? • Where to log? (file/db/…) • Who should have access to logs? • Incremental or rotation log? • How to purge/delete logs? 13 21.5.2010 - Pavel Růžička Product Development Department
Tracing - testing • How to test an application? • Which parts of the application should traceable? 14 21.5.2010 - Pavel Růžička Product Development Department
Monitoring - SLA • How it will be monitored? • Are there any special monitoring rules? • Use cases will help you best: • How to watch each particular use case? • What to watch/track there? (user/action/result) 15 21.5.2010 - Pavel Růžička Product Development Department
Transaction • Which operation is „atomic“- what must be proceeded all at once? • How to do rollback/cancel an operation? 16 21.5.2010 - Pavel Růžička Product Development Department
Naming conventions Name of a product/service and internal naming (Windows Chicago vs. Windows 2000) • E s t a b lis h in t e r n a l n a m in g c o n v e n t io n s – it w ill h e lp y o u t o a v o id o f t r o u b le s • in c a s e o f u n c le a r p r o d u c t n a m e • in c a s e o f c h a n g e t h e p u b lic produc t na me 17 21.5.2010 - Pavel Růžička Product Development Department
Caching, performance • Think about scalability • What to cache • What must be strictly online • Prepare fallback scenario in case of outage 18 21.5.2010 - Pavel Růžička Product Development Department
Sources • http://en.wikipedia.org/wiki/Non-functional_requirement • http://broadcast.oreilly.com/2010/02/nonfunctional-requiremen • http://www.stellman-greene.com/2010/02/17/nonfunctional-req 19 21.5.2010 - Pavel Růžička Product Development Department

More Related Content

Non functional requirements

  • 1. Non Functional Requirements 21.5.2010 - Pavel Růžička Product Development Department
  • 2. Knowing of non-functional requirements Helps to avoid of customers say „Y o u s h o u l d t h in g b e t t e r !“ 2 21.5.2010 - Pavel Růžička Product Development Department
  • 3. I t helps a lot if you know what is the “most critical“ non-functional requirement because this can dominate the best choice of development technique and internal design. 3 21.5.2010 - Pavel Růžička Product Development Department
  • 4. 4 21.5.2010 - Pavel Růžička Product Development Department
  • 5. Non-functional requirements are aspects • Users have implicit expectations about how well the software will work. • These characteristics include • how easy the software is to use, • how quickly it executes, • how reliable it is, • and how well it behaves when unexpected conditions arise. • The non-functional requirements define these aspects about the system. 5 21.5.2010 - Pavel Růžička Product Development Department
  • 6. Non Fuctional Requirements - General • Security • Exception Handling • Validation • Logging • Tracing / Testing • Monitoring / Reliability • Transaction • Storage • GUI Binding • Configuration 6 21.5.2010 - Pavel Růžička Product Development Department
  • 7. Non Fuctional Requirements– System / Dev • Naming conventions • Caching, Performance • Scalability • RAM usage • Thread Sync 7 21.5.2010 - Pavel Růžička Product Development Department
  • 8. Non Fuctional Requirements - Business • Time to market • Cost • Speed / Performance • Interoperability • Flexibility • Disaster recovery • Usability • Accessibility 8 21.5.2010 - Pavel Růžička Product Development Department
  • 9. How to fetch non-functional requirements? • A n t i- s t o r ie s are things the user does not want to happen, commonly for safety or security reasons. • N o way we let an I L OV E Y OU E M ail worm in our System! • U s e a c h e c k lis t  9 21.5.2010 - Pavel Růžička Product Development Department
  • 10. Security - Should access to be limited? - Is an access list necessary? - Access Control List - White List - Black List 10 21.5.2010 - Pavel Růžička Product Development Department
  • 11. Exception handling - What errors can occur on runtime? - What it should do in case of error? 11 21.5.2010 - Pavel Růžička Product Development Department
  • 12. Validation • Which input items are required? • Which of them need to be validated? • What to do if input is invalid? • How to recognize if an item is valid? (email, personal number, ZIP code...) Be aware - customer tends to change it frequently! 12 21.5.2010 - Pavel Růžička Product Development Department
  • 13. Logging • It is about loggin from the user perspective, not developer’s logging • Which events should be logged? • Which items should log contain? • Is the last operation enough or you need history? • How deep the history should be? • Where to log? (file/db/…) • Who should have access to logs? • Incremental or rotation log? • How to purge/delete logs? 13 21.5.2010 - Pavel Růžička Product Development Department
  • 14. Tracing - testing • How to test an application? • Which parts of the application should traceable? 14 21.5.2010 - Pavel Růžička Product Development Department
  • 15. Monitoring - SLA • How it will be monitored? • Are there any special monitoring rules? • Use cases will help you best: • How to watch each particular use case? • What to watch/track there? (user/action/result) 15 21.5.2010 - Pavel Růžička Product Development Department
  • 16. Transaction • Which operation is „atomic“- what must be proceeded all at once? • How to do rollback/cancel an operation? 16 21.5.2010 - Pavel Růžička Product Development Department
  • 17. Naming conventions Name of a product/service and internal naming (Windows Chicago vs. Windows 2000) • E s t a b lis h in t e r n a l n a m in g c o n v e n t io n s – it w ill h e lp y o u t o a v o id o f t r o u b le s • in c a s e o f u n c le a r p r o d u c t n a m e • in c a s e o f c h a n g e t h e p u b lic produc t na me 17 21.5.2010 - Pavel Růžička Product Development Department
  • 18. Caching, performance • Think about scalability • What to cache • What must be strictly online • Prepare fallback scenario in case of outage 18 21.5.2010 - Pavel Růžička Product Development Department
  • 19. Sources • http://en.wikipedia.org/wiki/Non-functional_requirement • http://broadcast.oreilly.com/2010/02/nonfunctional-requiremen • http://www.stellman-greene.com/2010/02/17/nonfunctional-req 19 21.5.2010 - Pavel Růžička Product Development Department