AlbaLed Posted October 29, 2003 Share Posted October 29, 2003 1. What's wrong, if anything with the waterfall model ? What are some other, may be better models? State how they work, their dis/advantages and what kind of projects are they meant for. 2. Approximately what percentage of the resources ($ or man hours) are spent doing maintenance? (kind of rule of thumb thing) Quote Link to comment Share on other sites More sharing options...
wood Posted October 29, 2003 Share Posted October 29, 2003 1. What's wrong, if anything with the waterfall model ? What are some other, may be better models? State how they work, their dis/advantages and what kind of projects are they meant for. Here's the link where I took it from: http://www.larc.nasa.gov/barkstrom/public/The_Standard_Waterfall_Model_For_Systems_Development.htm Add "http://asd-" before www above. For some reason, TM post is scrambling the html ref... Advantages:[*]Uses an easy divide-and-conquer approach [*]Several modules can be developed independently [*]Effective for large and complex projects [*]Allow departmentalization and managerial control [*]A schedule can be set with deadlines for each stage of development and a product can proceed through the development process like a car in a carwash, and theoretically, be delivered on time [*]Anything else? Anyone? Disadvantages:[*]Problems are not discovered until system testing. [*]Requirements must be fixed before the system is designed - requirements evolution makes the development method unstable. [*]Design and code work often turn up requirements inconsistencies, missing system components, and unexpected development needs. [*]System performance cannot be tested until the system is almost coded; undercapacity may be difficult to correct. [*]It can also be very expensive Other models:[*]Spiral Design (Go through waterfalls, starting with a very rough notion of the system and becoming more detailed over time) [*]Modified Waterfalls (Waterfalls with Overlapping Phases; Waterfall with Subprojects) [*]Evolutionary Prototyping (Start with initial concept, design and implement an initial prototype, iterate as needed through prototype refinement until acceptable, complete and release the acceptable prototype) [*]Staged Delivery (Go through Concept, Requirements Analysis, and Architectural Design - then implement the pieces, showing them to the customer as the components are completed - and go back to the previous steps if needed) [*]Evolutionary Delivery (a cross between Evolutionary Prototyping and Staged Delivery) 2. Approximately what percentage of the resources ($ or man hours) are spent doing maintenance? (kind of rule of thumb thing) Dunno!! Quote Link to comment Share on other sites More sharing options...
AlbaLed Posted October 29, 2003 Author Share Posted October 29, 2003 I think you got them, I added some of the links you posted to the "stiky" message on the top thread. 2. I think this is around 60% but I am not sure, looking for it thou Quote Link to comment Share on other sites More sharing options...
Vinay Posted October 29, 2003 Share Posted October 29, 2003 also other disadvantages of waterfall are: too rigid, you have to follow all steps in order. lots of unwanted documentation. Quote Link to comment Share on other sites More sharing options...
nonevent99 Posted October 29, 2003 Share Posted October 29, 2003 The biggest problem with the waterfall model is that you can't "go back" very easily. I've been a professional programmer for about 5 years, and in my experience, 80% of the money is spent on maintenance. It's a honking lot more than any customer ever imagines when they kick off a system. Quote Link to comment Share on other sites More sharing options...
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