[tahoe-dev] notes about DIR2:CHK deep immutability (maybe Tahoe-LAFS v1.6)

[James A. Donald]

James A. Donald wrote:
 > If one sets to synthesizing nice, but unnatural
 > properties, one is apt wind to up with the Xanadu
 > disease.

Not everyone may be familiar with the Xanadu disease, so
I will clarify:

Traditionally projects approach ninety percent complete,
and then remain ninety percent complete forever.
Project Xandadu, however, became less and less complete
with the passage of time, rapidly and asymptotically
approaching 0% complete.

As the final envisaged design became more and more
elegant, not only did the code become less and less
complete, but also the design became less and less
complete - less UI was prototyped, or even imagined, and
less of the implementation for that UI was envisaged in
sufficient detail to even start implementing it.

Thus first the implementation approached zero, then
design of the implementation approached zero, then
design of the ui to be implemented approached zero.