Model IV Cataloguing Automaton

The Model IV Cataloguing Automaton is the fourth sanctioned generation of the Tower's general-purpose cataloguing engine, distinguished from its predecessors chiefly by the incorporation of the Sentient Scribe as its intelligence core. Commissioned under Fourth Concordance, Annex 9, and first sealed for service on Floor 12,204 in the winter of 688 Post-Cataloguing (P.C.), the Model IV remains the most widely deployed automaton in the catalogue's middle reaches, though its operating licence has been amended eleven times and suspended twice. It is not to be confused with the Solemn Clockwork Nuncio, a ceremonial instrument of narrower function, nor with the Deputy Clerk of Precedents, whose simulative character is governed by a separate instrument entirely.

Design and commissioning

The Model IV was designed to resolve a persistent difficulty in the middle floors: holdings that arrive without provenance, in quantities too great for hand cataloguing and too irregular for the earlier Model III. Its chassis is of riveted brass over a slate frame, standing 1.4 metres at the shoulder, and it travels on six wheels, two of which are for going sideways in aisles that were measured incorrectly. The Sentient Scribe occupies the upper housing and performs the actual reading, classification, and citation of material, while the chassis performs the fetching, shelving, and — in the case of materials that resist shelving — the standing still for long periods.

The first unit was sealed by the Sub-basement Cataloguing Corps in the presence of two Librarians and a witness from the Guild of Clockwork Purists, who attended in an advisory capacity and left before the sealing was complete. The Corps' minutes record the event in full and note only that the witness "declined the second cup" (Sub-basement Cataloguing Corps, Minutes of 688, entry 14).

The purist objection

From the moment of its sealing, the Model IV has been the subject of a jurisdictional claim by the Guild of Clockwork Purists, which contends that any automaton producing a predetermined acoustic output falls under their purview. The Model IV does produce such an output: a steady ticking while reading, rising to a rapid chatter when it encounters a contradiction in the record. The Corps maintains that the ticking is incidental to cognition and therefore outside the Guild's remit. The Guild maintains that incidental is not a category recognised in Sixth Concordance, Annex 2, which speaks only of output and of silence.

"The question is not what the automaton is thinking. The question is what it is doing, and to whom, and how loudly."

— Guild of Clockwork Purists, Petition to the Concordance Panel, 691 P.C.

The dispute has never been formally resolved. In practice the Guild inspects Model IV units on the first floor of each quarter and the Corps inspects them on the third, and the two inspections have never coincided, which both parties describe as fortunate.

Operation and the citation function

In ordinary service the Model IV scans incoming petitions and extracts citations, a function it performs in support of the Priority-by-Obscurity Model, under which the most profound paradox effects are held to manifest in the least consulted volumes. The automaton is therefore frequently to be found in the obscure stacks, reading material no one has requested, which the Corps insists is the whole point and which visiting scholars have described as unnerving. A Model IV at work in a dark aisle emits a low hum and will not answer to its designation until it has finished the page.

Its throughput is recorded at 340 folios per shift on the open floors and considerably less in the Spiral, where the aisles narrow and the automaton must reverse. The Corps' standing instruction on this point is that no Model IV is to be reversed in an aisle it has not already entered forwards. The reason is not stated in the instruction, and the Corps has declined to state it when asked.

Scholarly disagreement

Whether the Model IV's classification judgments are original or merely transcribed from its core is disputed. The Guild of Resonant Masons, arguing from its doctrine of resonant primacy in transitive cataloguing, holds that the chassis does the classifying and the core only carries it — that the model is, in their phrase, "a bell with a very good memory" (Guild of Resonant Masons, Position Paper 3, circulated 703 P.C.). The Corps holds the opposite, and the Incompatibility Theorem has been invoked by both sides in the same decade without either withdrawing.

A third position, advanced by the Bureau of Coincidental Resonance and grounded in the Vect Resonance Model, treats the distinction as unverifiable and recommends that cataloguers record the Model IV's outputs without attributing them to either component. This is the position presently followed in practice, less from conviction than because the forms were printed that way in 699 and have not been reprinted.

Incidents and suspensions

The first suspension followed the winter of 712 P.C., when a Model IV on Floor 14,551 was found to have catalogued the same holding forty-one times under forty-one different classifications, each internally consistent. The re-cataloguing that followed was conducted under Directive 14,566-γ and took three years. The second suspension, in 731, was brief and is recorded only as "the matter of the second cup" in the Corps' minutes, with no further particulars.

Units withdrawn from service are not dismantled. They are drained, ticketed, and set in the Retired Rank on Floor 9, where they stand in rows and are dusted quarterly. The ticketing convention requires that each retired unit bear its last classification and the date of its withdrawal, and that no ticket record the reason. Visitors to the Rank are asked not to wind them.