Why we keep both versions

01:20 The request came down from upstairs at the end of a night shift, which is when requests usually come down: a call-out record, one sequence number, two contents. By the time it reached the basement it had already been validated, locked and filed twice, and there was nothing left for anyone to do but look at it.

Two records, one number

Dispatch assigns sequence numbers at the moment of sending, one per message, no exceptions. That is the whole guarantee the rest of the city leans on. So when two messages carry the same number, the first instinct is to ask which one is real. The depository does not ask. It stores both, with equal care and equal archival value, without comment and without preference.

What the act says

The rule is older than most of the people who apply it. It was written when the most advanced medium available was a three-and-a-half-inch floppy disk, and it has not been rewritten since, only extended.

The act guarantees the preservation of information. It does not guarantee the telling of truth from falsehood, and it was never meant to. That is somebody else's job, and the depository is careful not to do it by accident.

The system does not judge the content of what it archives — only the format.

The CDI, entry in the city encyclopedia

Reading the log

What the depository keeps beside the data is often more useful than the data. Timestamps, the direction of a connection, the fingerprint of the certificate a device presented at the door. Here is the night, as the intake printed it.

01:18:02  login   sync-if     v.brenn    vpn
01:20:00  recv    0041-877    dispatch   valid
01:20:00  recv    0041-877    dispatch   valid
01:20:01  lock    0041-877    x2         stored
01:20:01  cert    #a3f9..c2   issuer     internal-ca

One line in that printout is not like the others. It is the kind of thing a person in this department rings in pencil before she knows why: the certificate fingerprint #a3f9..c2, which turns up again in four older records that nobody had any reason to open.

What the four older records have in common

1. A duplicate with a matching sequence ID
2. An identical timestamp to the second
3. No real-time system downstream to notice
4. The same fingerprint at the door

The inactive branches

Records judged invalid, obsolete or duplicate are not deleted. The act does not allow it. They are moved to passive storage, the department in the basement, where they wait for an inquiry that almost never comes. By law the department is open to anyone who asks. In practice it is visited by cranks, historians and, once in a long while, somebody who needs it.

Upstairs the building shows the self-assurance of the state in tonnes of marble. Down here it economises on everything, the fluorescent tubes included. The records do not mind. They lose their contour in passive storage, never their existence.

The rack — blue and green diodes, the drone of fans

A reader yet to come

Somebody in this department once said that the records would outlive everyone present, and that information once radiated out into the world is not lost, whether anyone reads it or not. The tablets from Crete lay three thousand years in the earth and waited. The two call-out records will lie side by side in the depository and wait as well — for a reader who will think it matters which version was the right one.

Both valid, both locked, both forever.