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Doing a bit-for-bit restart with a new directory/machine/executable is called "branching" in CESM/ACME nomenclature. See the startup/branch/hybrid in CESM1.0 Documentation for a description. Note that one can also "clone" a case, which is like branching but preserves local modifications to the code base you're using (see how to clone in CESM1.x User's Guide). Since all good acme coders check all their changes into git before doing a run and because cloning is complicated, we shouldn't need to clone. This CESM documentation explains how to set up a branch run: branching in CESM2. Documentation. I didn't think the branch utility worked for ACME v1 coupled runs, so I wrote a description for how to branch manually below. It turns out the utility does work (at least using the run_acme.csh script for FC5AV1C-01 and A_WCYCL2000), so I include a description of using that simpler method as well. Note: while the "branch" utility worked on a simple test case, I can't get it to work for more complex cases. Buyer beware.
Continuing a run using NCAR's "branch" utility and the run_acme.csh script:
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