Glossary FDLnotes

Certificate Staleness Processing State

The management of Stale Certificates involves some extra state beyond which certificates of the current closed map are deemed stale. Recall that the ordinary state of the current closed map is that there are no stale certificates, and that staleness is intended as a temporary state; failure to eliminate staleness results in failure of the original operation and restores the current closed map to its original "prestale" state.

In addition to the finite collection of stale certificates, there is for each stale certificate a collection of those objects that it simply refers to whose contents have changed since the prestale current closed map; and each of those entries in the "changed object" collection is paired with the prestale value, which the certificate was presumably originally about. The purpose of this, as explained in Staleness (pertinence), is to anticipate reconsideration procedures that leave the certificate intact based upon some relation between the old and new values that is deemed irrelevant to the the correctness of the certification. It is also possible that even if reconsideration does change the certificate content, thus forcing propagation of staleness to further pertinent certificates, knowing the difference between the old and new contents of simply referenced objects may permit a more efficient incremental recertification than simply rerunning the certificate's origination procedure.

When the content of any object is updated, each certificate simply referring to it is marked stale if it is not already so marked. Further, for each of these certificates the object is added to its "changed object" collection along with the prior content, unless it is already in the collection, in which case it is left as is.

Another operation on the current closed map that changes the staleness state is Folding, which "identifies" some distinct object identifiers with each other. For each stale certificate there is a "folded object collection" of the objects that it simply refers to that resulted from such an identification of originally distinct identifiers. Similarly to the content change case above, the purpose is to admit the possibility of leaving the certificate intact or enable a more efficient incremental recertification.

Upon Folding the current closed map, any certificates that simply refer to any of the newly "identified" objects are marked stale if not already so marked, and the identified objects get inserted in this folded object collection. It should also be noted that the extant "changed object collections", "folded object collections" and the stale object collection must themselves be collapsed to reflect the new identifications.

Another operation is simply to mark a certificate as stale even if nothing it simply refers to changes in order to express doubt for external reasons. In order that the nature of this doubt may be communicated to the procedure for reconsideration, this operation takes a Text as argument to be saved with the stale certificate. With each stale certificate, therefore, is associated a (finite) collection of these "staleness fiats"; this operation then consists of marking a certificate as stale, if it's not already, and adding the given "staleness fiat" to the collection for that certificate.

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Glossary FDLnotes