replace-a-system-without-guessing

The procedure as a graph, on its own page — zoom it, print it, send somebody the address. Back to the record for the steps, the trust panel and the provenance.

Procedure

The same procedure, read in order

  1. start start. Goes next to s1
  2. decision Can you still reach the incumbent?. Goes if access_gone to s2; if default to s3
  3. action Say plainly that there is no baseline, RO (read-only). Goes on_fail to s9; next to s4
  4. action Run real questions against it, and record, RO (read-only). Goes on_fail to s9; next to s4
  5. action Mark which answers must not get worse, RO (read-only). Goes on_fail to s9; next to s5
  6. action Run the same questions against the new one, RO (read-only). Goes on_fail to s9; next to s6
  7. decision How does it compare?. Goes if critical_worse to s9; if non_critical_worse to s7; if default to s8
  8. action Fix it and run the set again, RW (reversible-write). Goes retry to s5; next to s9
  9. action Cut over, with a date and an owner, IRR (irreversible), requires approval. Goes on_fail to s9; next to s10
  10. check The old one is actually gone. Goes on_fail to s9; next to __end_success
  11. escalate Do not switch yet. Terminal
  12. end success. Terminal