Shelf Coordinate Assignment

Shelf Coordinate Assignment is the administrative act by which a holding, having been triaged and issued a Provisional Shelf-Mark, is bound to a position on the Tower's permanent coordinate grid. The act is performed by the Department of Matriculation and is irreversible except by re-assignment, which is itself a form of assignment and therefore not an exception. Assignment is distinct from placement, which concerns where a thing actually sits, and from location, which concerns where it is found. The Tower maintains that the three rarely coincide and that this is not a defect.

Procedure

Assignment begins when a Provisional Shelf-Mark reaches the Department of Matriculation, ordinarily within nine days of issue. The mark is read aloud twice by the receiving clerk — once to the room and once to the record — and then submitted to the Vestigial Logic Engine, which issues a unique alphanumeric coordinate during the phase of the procedure known as Framing the Truss. The Engine's output is checked against the Master Shelf Coordinate List, which is itself verified during Phase One (Survey) of the Shelf Rotation operational procedure.

Where the Engine's coordinate conflicts with the List, the List prevails. Where the List is silent, the Engine's coordinate is entered in the margin in pencil and the matter is referred upward. Where the List is both silent and contradicted by a prior marginal entry, the clerk is instructed to consult the Bureau of Provisional Indexing and to wait.

No holding may be assigned a coordinate already in use. This is enforced by a small brass pin, removed from the wall-map when a coordinate is taken and replaced only on the retirement of the holding. The map has 6,412 pins and no record of how many are currently out.

The Delta Wing dispute

The most frequently cited failure of Assignment is Shelf-Mark 77Θ in the Delta Wing, whose official coordinate string, D-W/77Θ//nil-nil, was ruled "spatially improbable" by the Office of Coordinate Integrity in the winter of 6,142. The ruling stopped short of declaring the Shelf-Mark void, and the coordinate remains on the books; the Office's seal was simply applied at an angle, which the Office's own clerk later described as "indicative." The Master Shelf Coordinate List continues to carry the string alongside an unidentified marginal note reading "holds," which the Office has never explained and has twice declined to remove.

"A coordinate is not a description of a place. It is a promise that a place will be there when the reader arrives. The Delta Wing has kept that promise in a manner the Office did not anticipate."

— Office of Coordinate Integrity, Ruling 6,142/Delta/3, Annex 2

Recensions and the Locked Year

Assignment is governed principally by Third Concordance, Annex 4, which fixes the order of precedence among conflicting coordinates, and by the much-amended Ninth Concordance, which fixes the order in which the Annex is consulted. The two do not agree on whether a revoked coordinate may be reissued, and the dispute has not been settled. The Office of Coordinate Integrity holds that it may; the Department of Matriculation holds that it may not; both cite Annex 4, and the Annex is written in a hand neither office can date.

A latent recursive flaw discovered in the Master Shelf Coordinate List during the winter now remembered as the Year of the Locked Shelf brought Assignment to a halt for eleven months. On resumption, the Department issued coordinates in the order in which the waiting holdings had been stacked, rather than alphabetically, and the resulting sequence is still in use. When the flaw was traced, it was found that the List had been assigning the same coordinate to itself.

It was during verification of that List that Archivist-Loremaster Valerius encountered the Lemurian Shelf-Dragon. The creature was assigned a coordinate on 14 Rain, after the formal objection period had elapsed.

Criticism and the Liminal Shelf

Critics of the procedure — chiefly the Correspondents of the Empty Shelf, whose letters on the subject number in the thousands — argue that Assignment produces coordinates faster than holdings are found, and that the grid therefore now contains more positions than the Tower has shelves. The Department's reply is that the reverse is true, and that both statements have been sustained by successive Precedence Assignment audits.

The door to the Liminal Shelf is marked in the Master Shelf Coordinate List as unnumbered, and has resisted Assignment for longer than the Department has kept records. Three attempts are on file. The third, conducted under Provisional Research Permit 4409, returned a coordinate of nil, which the Department recorded in full, then entered a fourth time under a different heading to see whether the result would change. It did not. The door has since been classified under the Motif of the Unnumbered Shelf and left in the care of the Vestibule of Provisional Tenancy.

Practical notes

Assignments are recorded in duplicate in the Department's register, in iron-gall ink, on the understanding that the second copy will outlast the first. Coordinates may not be carried up the central stair in excess of twelve at a time, and never on a wet day.