Name two of the software development models (lifecycles) described by Sommerville or McConnell. Provide a 1-2 sentence description of each. (One point each.)

• Waterfall -- Go through every phase of development just once. Don't go back to any previous phases. Plan the project carefully, then execute it.
   
• Overlapping (or modified) waterfall -- Like above, but during each stage you can go back somewhat to the stage before.
   
• Code-and-fix -- Begin coding immediately. Debug as you go. Do everything all at once.
   
• Spiral / evolutionary / staged delivery  -- The entire development process is done several times, each time getting better than before.
   
• Design to tools -- Create software that is easy to do, given the development tools you are using.
   
• Design to schedule -- Fit the size and features of the software into the required schedule end date.
   
• Commercial off the shelf -- Don't develop software at all; buy it already created from someone else.