Waterfall model

Waterfall model 

CIA CD ITM

The waterfall model is a sequential design process, often used in software development processes, in which progress is seen as flowing steadily downwards (like a waterfall) through the phases of Conception, Initiation, Analysis, Design, Construction, Testing,Production/Implementation, and Maintenance.

1. its from top to bottom.. *say if we have 100 bottles, then all 100 bottles will fall to bottom
2. Its goes step by step
3. Once planning, then analysis, and when analysis totally done, then we go to design and so to next stages and finally we do testing. That's why its called sequential process. WE can go back but way its structured, we can't go back. 
4. Its old 
5. Work is done in stages
6. Also interviews conducted in each phases
7. Planning is major phase..where we do budget,
8. Its liner and sequential is useful when we have clear model 
9. Its not useful when we don't have clear 
10. its time consuming
11. We need always excessive documentation
12. Its excessive documentation model
13. If requirement keep changing then its not useful