Look at the last page, Figure 10. This illustrates the model he says works, and it's clearly a form of waterfall.

Sorry, but you are wrong.

The bit of fig.10 that looks like the waterfall model -- the bit to the right of the dashed line -- is simply a reiteration for contrast of fig.4, of which Royce says (in the text above fig.4):

I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input/output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code will not fix these kinds of difficulties. The required design changes are likely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modified, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.

The bit of fig.10 to the left of the dashed line is his alternative designed to correct the flaws in the waterfall model, which with its feedback loops and iterative processes is clearly the antithesis of the (no going back; never throw anything away) waterfall model.

Instant analysis doesn't cut it here.

The bit of fig.10 to the left of the dashed line ... is clearly the antithesis of the ... waterfall model.

I disagree with you. But I won't say "you are wrong", because there is no objective reality here.

On the other hand, you were wrong about the origin of the quote. :-)

I disagree with you. But I won't say "you are wrong", because there is no objective reality here

You say you are disagreeing with me; implying by the dint of what you quoted, that what you are disagreeing with, is my interpretation of Royce.

But it is not my interpretation, but rather the general interpretation of:

1. Royce:

   From wikipedia, which whilst not definitive, has sufficient openness to cross-examination, to avoid major single-sourced opinion errors which says:

   In Royce's original waterfall model, the following phases are followed in order:

   • Requirements specification
   • Design
   • Construction (AKA implementation or coding)
   • Integration
   • Testing and debugging (AKA Validation)
   • Installation
   • Maintenance

   Thus the waterfall model maintains that one should move to a phase only when its preceding phase is completed and perfected. However, there are various modified waterfall models (including Royce's final model) that may include slight or major variations on this process.

2. The obvious, common-sense interpretation of the term Waterfall Model:

   From Hutchinson Concise Encyclopedic Dictionary: 'Waterfall': a stream or river flowing over a steep precipice.

   Water does not flow uphill; the waterfall model does not iterate.

The fact that you cannot test until you have some code; and cannot code until you have some design; cannot design until you have some requirements; means that any methodology has to show those steps being started in the same order as listed above.

The single thing that distinguishes the waterfall model, from all other models, is the absence of feedback loops and iterative processes. The moment you add any kind of feedback or looping; the waterfall analogy is broken and you are talking of a different model.

It is not -- cannot be -- a modified waterfall model once you add feedback and iteration.

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With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

The start of some sanity?