139: Chapter 139 Echoes from 2096

In the winter of the fifteenth year, after G-Explorer-B completed its final long-distance expedition verification, Jiang Lin reopened a black marker that had remained silent on the map for eight years.

Northeast of the Outpost, at a straight-line distance of about seventy-three kilometers.

Temporarily marked as: [Northeast Seventy-Three Abnormal Collapse Zone].

As early as the seventh year, Jiang Lin already knew that an anomaly existed there.

At that time, he did not yet have G-Explorer-B.

That antiquated early expedition platform, G-Explorer-A, had just barely been able to leave the Outpost, perform short-distance detachment reconnaissance, and use foot-end contact states to reversely correct terrain risk maps.

However, its long-distance retreat redundancy was insufficient, the signal-to-noise ratio of its communication relay chain hovered at a critical point year-round, and drone coordination remained only at a barely usable stage.

More importantly, it had not yet proven itself in expeditions on the scale of seventy kilometers.

And Northeast Seventy-Three was not the kind of scree slope around the Outpost where trial and error could be repeated indefinitely.

It was too far away, and too much like a geological trap that would swallow equipment and clues together.

In fact, that discovery in the seventh year did not stem from naked-eye intuition, but from a set of dry remote sensing raster matrices.

At that time, in order to let G-Explorer-A go further, Jiang Lin temporarily wrote a field map module.

A Wasteland geographic information system pieced together from a set of map-stacking scripts, risk annotation tables, foot-end contact dynamics data, and visible light, near-infrared, and 1550nm short-wave infrared ranging data.

When Jiang Lin initially wrote it, it was to avoid risks, not to search for ruins.

But in that round of high-altitude aerial surveys in the northeast direction, the field map module gave an abnormal prompt for the first time through the superposition calculation of infrared radiation and surface reflectance.

[System Warning: The surface contour contains non-natural geometric remnants.]

Thus, from the seventh year to the fifteenth year, Jiang Lin never let this coordinate disappear from the database.

Every once in a while, he would have high-altitude drones retake photos of that collapse zone from different altitudes, different seasons, and different solar altitude angles.

Wind and sand covered a portion of the superficial clues.

The short-lived surface runoff of the rainy season washed out the roughness of certain edges once again.

What Jiang Lin truly valued was the thermodynamic response at the center of the collapse zone during the alternation of day and night temperature differences.

In the process of absorbing solar radiation during the day and radiating heat outward to cool down at night, the thermal conduction of normal geological structures followed Fourier's law, but the thermal inertia distribution of Northeast Seventy-Three showed a fault.

Jiang Lin established a simplified thermal diffusion model on the terminal to analyze the heat flux of that region.

After up to eight years of data accumulation, he discovered that the cooling curve of the central region was consistently half a beat slower than the surrounding natural weathering slopes.

This meant that there was a high probability of some structure underground that altered the path of thermal diffusion.

It could be a cavity with extremely high thermal resistance, or a massive man-made object whose specific heat capacity was completely different from the surrounding geology.

Until the winter of the fifteenth year, he reopened this map that had been silent for eight years.

[Surface contour contains non-natural geometric remnants]: Multispectral scanners showed that the area had regular linear reflectance mutations in the visible-near-infrared band, while exhibiting abnormal attenuation in the 1550nm echo intensity.

[Suspected underground structure collapse negative]: The surface subsidence gradient matched the mechanical collapse characteristics of a large rectangular frame after failure.

[Half-buried circular depression continuously visible]: A geometric flow-suppression area that wind and sand could not completely fill.

[Thermal inertia anomaly stably exists]: The day-night cooling curve at the center of the collapse zone lagged for a long time, suggesting the existence of a deep structure below that altered the path of thermal diffusion. Combined with low-frequency geo-acoustic echoes and multi-year subsidence gradient inversion, the suspected anomaly body was buried at a depth of about 30 to 50 meters.

In the spring of the sixteenth year, the earth warmed up and atmospheric turbulence tended to stabilize.

Jiang Lin officially initiated close-range reconnaissance of the Northeast Seventy-Three Abnormal Collapse Zone.

Twenty kilometers away, the familiar landforms began to disappear.

The dark red caked soil, gentle scree slopes, dried gullies, and safe retreat points around the Outpost that had been repeatedly marked by Jiang Lin were gradually left behind.

Further ahead was a relatively unfamiliar Wasteland.

The surface here presented a morbid grayish-white.

Large areas of scree slopes connected together, spread across the surface like a layer of bone meal ground up by an industrial grinder.

Several deep wind-eroded gullies cut diagonally across from the northeast direction, with deeper dark red gravel deposited at the bottom of the gullies.

In the cold and hard light of the sky, the distant low wind-eroded tablelands appeared extremely flat, so flat that they lost all the randomness that natural creations should have.

He stopped once at the sixty-fifth kilometer and dropped the first communication relay node.

The node deployed its antenna, and the directional finder driven into the ground began self-calibration.

At the seventy-kilometer mark, he dropped the second communication relay node.

The two nodes, the high-altitude relay drone, and the main antenna of the Outpost formed a microwave communication link.

Jiang Lin stood beside the motorcycle, observing that grayish-white collapse zone with an optical telescope featuring a ranging function.

G-Explorer-B was released from the towing rack.

Its forelegs compacted the scree, its middle legs fine-tuned the support torque, and its hind legs deployed into a low-center-of-gravity posture. The servo motors and piezoelectric ceramic actuators inside the fuselage emitted a low buzzing sound of current.

After completing its self-check, G-Explorer-B performed three rounds of complex foot-end contact dynamics calibration on the spot.

Low-pressure contact: Measuring the thickness of surface loose sediments.

Lateral perturbation: Evaluating the surface friction coefficient and shear strength.

Center of gravity bias feedback: Testing the uneven settlement limit.

The onboard motherboard quickly solved the impedance control equations, and on the screen, the field layers began to refresh.

[Surface hardness: Medium (Estimated bearing capacity 120 kPa)]

[Scree slip probability: Slightly high]

[Local micro-vibration feedback: Abnormal (Low-frequency resonance attenuation too fast)]

[Recommendation: Advance in a low posture, limit joint angular velocity]

The surface on the periphery of the abnormal collapse zone finally provided contact feedback corresponding to the aerial survey residuals from eight years ago.

There was indeed something underground, and its structural rigidity was vastly different from the surface soil layer.

G-Explorer-B walked exceptionally slowly.

Before every step landed, the foot end would hover for an extremely brief moment.

Contact.

Servo motors applied force to compact.

Rebound micro-change measurement.

Calculating the support polygon, smooth load transfer.

Fuselage posture fine-tuning.

The next step.

When it was about eight hundred meters away from the center of the collapse zone, the first anomaly on the physical level was confirmed.

In the high-altitude footage from the drone, that was just a slightly gentle scree slope with no abnormalities whatsoever.

But after G-Explorer-B's front right foot landed, the contact confidence fed back by the main controller plummeted from ninety-two to sixty-one.

The next step, the front left foot readings were normal.

The step after that, the middle right foot experienced severe delayed rebound again.

The chassis inclination sensor captured an abnormal tilt of 0.4 degrees.

Discontinuous, uneven.

Beneath the surface, it was like a thin-shell structure whose base had been hollowed out; it looked solid, but in reality, as long as the pressure exceeded the critical point, it would shatter instantly.

G-Explorer-B followed the conservative safety strategy set by Jiang Lin, immediately lowering its posture and crouching down, extending its six legs outward to maximize the contact area and reduce ground pressure, looking like a black arthropod clinging tightly to the grayish-white surface.

A highlighted prompt popped up on the screen.

[Warning: The area ahead is suspected to be a thin-shell surface (stress distribution interrupted)]

[Recommendation: Replan path, detour]

Jiang Lin pressed Enter, accepting the recommendation.

G-Explorer-B detoured along the high-stress feedback zone on the southwest side.

Half an hour later, it reached the first crack opening judged to be low-risk in the peripheral zone.

The crack was not wide, with the widest point being no more than eighty centimeters, and the outside was blocked by a large amount of weathered scree.

If manual cleaning or mechanical expansion were performed, the entrance could be enlarged a bit more.

But Jiang Lin did not act rashly.

He remotely activated the dust-proof sealed cabin on G-Explorer-B's back, releasing a drone.

This drone was only the size of a palm. Its front end was equipped with a high-penetration narrow-beam LED lamp head and an ultra-wide dynamic range low-light lens.

Both sides were covered with anti-collision soft rings filled with non-Newtonian fluid, and the tail dragged an extremely thin Kevlar-reinforced fiber optic data cable.

In the underground where electromagnetic shielding and unknown interference might exist, hard fiber optic connections were the only reliable transmission medium.

The drone's maximum physical descent depth was forty meters.

Jiang Lin switched the operation console's flight mode to manual-assisted with force feedback.

In such a dim and cramped space, one could not completely trust machine vision and automatic obstacle avoidance algorithms.

The reflection cross-section inside the crack was extremely complex, and the scree could loosen at any time.

In certain narrow spots, the algorithm would refuse to advance due to being overly conservative, or it might misjudge the spatial depth due to missing environmental textures, crashing directly into the rock wall.

The drone clung to the edge of the crack, its rotors emitting a faint hum as it slowly descended.

Depth: Five meters.

The screen was filled entirely with naturally weathered scree and grayish-yellow dust deposits.

Depth: Twelve meters.

The color of the soil layer abruptly changed.

As the searchlight swept across, a large number of forcefully crushed concrete blocks appeared.

On the cross-sections, one could even see exposed metal rebar, their surfaces covered with a thick layer of dark red rust.

Depth: Nineteen meters.

A grayish-white flat structural surface was swept by the light, its surface exhibiting a honeycomb-like fracture texture, resembling some lightweight composite armor material that had been sintered at ultra-high temperatures and then forcibly torn apart by massive shear forces.

Depth: Twenty-seven meters.

The drone's light captured a section of a tubular component that had been crudely sheared off.

That component was nested from several layers of different materials, and at this moment it was bent into an unnatural acute angle. The surface layer was covered with dark, unknown sediments, the layered structure at the fracture was extremely dense, and the inner wall even had dried crystals.

The crack was getting narrower and narrower.

Every time the drone descended half a meter, the anti-collision soft ring would inevitably rub against the debris on both sides, stirring up minute dust.

The screen began to experience high-frequency shaking.

Depth: Thirty-one meters.

The narrow-beam lamp head penetrated a dense gap of scree, sweeping further into the depths.

Suddenly, he saw a man-made object.

It had a dark gray-to-black engineering composite material surface.

It featured smooth arcs conforming to fluid dynamics or some pressure vessel design.

The material was heavy, and the surface retained obvious traces of being ablated by ultra-high temperature plasma, with some parts even undergoing irreversible ceramicization.

Overall, it looked like the shell of some huge underground sealed structure that had been torn out by geological changes and was stuck obliquely in the stratum collapse zone.

And on the edge of that charred shell, there was an incomplete nameplate.

It looked like a high-temperature-resistant ceramic identification layer embedded directly inside the shell after being sintered.

Half of the identification layer was already cracked, and the other half was pressed down by the collapsed scree above.

Jiang Lin held his breath and gently pushed the joystick.

The drone's lens slowly moved closer.

The narrow-beam light produced a Tyndall effect in the dust, its halo trembling slightly.

The operation console's image enhancement algorithm began running at full load, performing multi-frame noise reduction and contrast stretching on the dim video stream.

The first row of incomplete English characters and numbers combination emerged from the shadows.

[TM-7 RSCA]

At the lower right of that line of letters, there was another independent mark with smaller font and deeper engraving.

[PMCU-17]

Jiang Lin's gaze was locked onto the screen, his brain operating at high speed.

He did not know what TM-7 RSCA represented at all, nor did he know what equipment serial number PMCU-17 actually was.

But judging from its level of materials science, manufacturing craftsmanship, and the scale of the engineering deeply buried underground, it belonged to a highly industrialized civilization system that possessed massive organizational power and had once constructed complex underground network engineering here.

Jiang Lin did not let the drone continue to approach at risk, but instead switched back to the automatic retraction mode, letting the drone slowly retreat along the original path, guided by the traction of the fiber optic cable.

Discovering artifacts of civilization was one thing; bringing them out intact from the depths of the earth was an entirely different matter.

Before excavation, Jiang Lin utilized the 3D modeling of high-altitude drones, low-frequency geological echo samplers, and G-Explorer-B's high-density foot-end contact matrix data to repeatedly calculate the angle of repose of the soil on the periphery of the collapse zone and the stable boundaries of the support structure's microwave link.

Formulating a rigorous preliminary reconnaissance plan.

Until it was confirmed through geological tomography that the location of PMCU-17 belonged to exposed debris that had been forcibly squeezed out to the edge of the core collapse zone by bottom shear forces during a severe earthquake.

It had already detached from the main underground structure, and the surrounding geological stress was already in static equilibrium.

Only then did he begin to approach and carry out cleanup work.

Beneath the Northeast Seventy-Three Abnormal Collapse Zone was a complex mixture sheared by earthquakes, compacted by the upper soil, and displaced during crustal movements.

Ordinary scree, fractured reinforced concrete, ceramic layers with high-temperature sintering marks, composite material revetments that had undergone severe plastic deformation, high-strength carbon fiber reinforcement bars bent to the verge of fracture, cooling pipes filled with crystalline impurities inside, and a large number of special composite insulation interlayers whose purpose Jiang Lin could not identify even after searching through all databases.

These things had undergone untold years of subsidence, water vapor erosion, and the intense saline-alkali chemical reactions unique to the Wasteland.

They had penetrated and cemented into one another, forming a perverted collapsed mass that possessed the hardness of rock yet was as difficult to separate as chewing gum.

If one had a heavy tracked excavator on hand, equipped with a hydraulic breaker, along with a complete deep-well engineering support system and total station surveying equipment, this excavation might have taken only a few weeks.

But Jiang Lin had nothing.

He only had the tiny pulling force provided by the G-Explorer-B, an angle grinder, a few homemade hot-melt cutting knives, and a manually modified pulley block...

And endless patience.

It was not until the seventeenth year that the main outline of the PMCU-17 finally emerged slowly and completely from the edge of the rock-solid collapse zone.

The true volume of this equipment was far more massive than what was seen through the drone's lens.

The main contour was approximately 2.4 meters long, 85 centimeters wide, and 55 centimeters high.

The shell presented a light-absorbing dark grayish-black color.

Large areas of the surface had undergone extreme ceramic ablation.

The area close to the stress-bearing surface was densely covered with fine honeycomb-like stress-relief cracks.

Jiang Lin took off his gloves and pressed his palm directly onto it.

The touch was ice-cold, and his fingertips could feel a subtle graininess.

Through the feedback of the mechanical jack, Jiang Lin calculated that its residual weight exceeded four hundred kilograms.

It did not look like an independent machine, but rather like a sealed equipment cabin forcefully torn from the interior of some giant armored wall by an extremely violent external force.

The alloy structural shell on the left side was severely collapsed, as if it had been directly punched in by an unspeakable heavy hammer.

The huge cooling interface at the rear was broken and deformed, exposing the multi-layered high-pressure pipelines inside, stacked layer upon layer and as complex as human blood vessels.

At the bottom, a group of optical interconnect tail cables responsible for high-speed data transmission had been brutally torn apart, and the optical fibers at the cross-section were as fine as a bundle of transparent hair instantly frozen by liquid nitrogen.

The heavy locks on both sides originally used for track fixation were twisted and deformed, and several composite guide rail remnants that were Physics-cut remained firmly embedded within the locks.

After spending another full eight months and experiencing countless hazards of pulley block slippage and support frame deformation, Jiang Lin finally dragged this four-hundred-kilogram black monolith out of the abyss and transported it back to the Outpost.

Afterwards, he spent another three months in the maintenance workshop completing the first round of non-destructive appearance inspection and surface cleaning on this PMCU-17.

The most critical breakthrough occurred in the spring of the nineteenth year.

That incomplete nameplate was completely cleaned out with a special solvent, and the remaining letters and logos finally pieced together complete information.

[TM-7 Regional Subterranean Computing Array]

[Periphery Maintenance Computing Unit]

[Outer Ring Service Layer]

[System Status: Sealed]

[Access Level: Diagnostics Only]

RSCA was very likely the abbreviation for Regional Subterranean Computing Array.

After Jiang Lin translated it into Chinese, this name appeared in the database for the first time: Regional Subterranean Computing Array.

When Jiang Lin entered these texts into the database, his brows could not help but furrow.

This equipment codenamed PMCU-17 was not some independent detector or weapon module he had initially imagined, but rather an outer ring maintenance unit of a regional subterranean computing array.

The contradictions and doubts in engineering logic came rushing in like a tide.

Between the literal meaning and Physics reality, several obvious contradictions spanned across.

First, the contradiction between volume and weight.

If it was merely an edge node responsible for outer ring maintenance, why would it need to adopt such an exaggeratedly thick composite armor shell?

For a routine maintenance unit, an equipment cabin with a residual weight of four hundred kilograms had an unreasonably large protective redundancy.

Second, the contradiction in interface specifications.

The nameplate read diagnostics and sealing only, but at its torn bottom, Jiang Lin saw a broken section of an optical interconnect tail cable with an extremely high security level.

Why would a device in a sealed state, used only for low-frequency diagnostics, reserve such a large Physics bandwidth for data throughput?

Third, the contradiction in thermodynamic design.

Although its cooling interface was already deformed, judging from the diameter and residual structure of the multi-layered pipelines, this was by no means used to dissipate heat for a few simple monitoring chips.

The Physics specifications of this cooling bypass could even support the phase-change heat dissipation requirements of high-density computing power clusters.

Why would an edge maintenance unit of a regional project need this level of protection, bandwidth, and heat dissipation capability?

Therefore, PMCU-17 looked like an edge maintenance unit on the outside, but its Physics skeleton was a heavy main battle tank.

This sense of incoordination emanating from the Physics wreckage was like an exam question with no known axioms to apply, forcing him to re-examine the massive, never-before-seen subterranean system.

Jiang Lin had to temporarily put down his wrench, return to the workstation, and catch up on the Physics organization methods of those grandiose systems.

Distributed system state machines based on Byzantine fault tolerance.

Redundant fault-tolerant computing architectures in high-radiation environments.

Ultra-large-scale phase-change liquid cooling and heat management networks.

Near-storage computing models integrating storage and computation.

Graph computing and topological constraints in complex networks.

Automata theory based on symbolic constraints.

...

Time advanced to the winter of the nineteenth year.

The world outside was blizzard-swept, but the maintenance workshop of the Outpost was warm and quiet.

After conducting hundreds and thousands of resistance tests and perspective scans, Jiang Lin finally found a group of low-voltage emergency wake-up interfaces suspected of belonging to the underlying architecture at a severely damaged interface area on the rear right side of PMCU-17.

This group of interfaces was hidden extremely deep.

In normal system design, it should have been strictly protected by the high-strength sealing layer and electromagnetic shielding cover of the shell, and would only be Physics-activated during high-level authorization or a complete collapse of the main system.

Now, due to the squeezing pressure brought by the crustal movement back then, the shielding layer had cracked, just revealing a row of pyramid-shaped contacts no thicker than a hair's breadth.

Jiang Lin's hand holding the probe paused on the start button of the isolated power supply module.

It hovered for a full ten seconds.

Deep inside his heart, he was extremely eager to know whether there was still any electrical signal response remaining in this black metal block.

Even if it was just the most primitive buzz when the motherboard was powered on, even if it was just a meaningless garbled character flashing across the screen.

But in the end, he forcibly restrained his impulse and pulled his hand back.

The internal circulation pipelines of this machine were completely broken and exhausted, and the phase-change coolant had long since leaked and evaporated completely.

The silicon-based transistors or unknown computing media inside the remaining core packaging were currently in an extremely high-risk heat-sensitive state.

Under the condition of no reliable heat conduction pathway, even a low-voltage small current could form uncontrolled hotspots at unknown short-circuit points, local breakdown zones, or residual high-impedance channels, instantly burning down the surviving data core.

In the nineteenth year, Jiang Lin began to build an external cooling bypass for this wreckage.

The so-called repair was not restoring the factory system at all, but rather an engineering gamble full of compromise and innovation.

He did not have the original factory recipe of insulating phase-change coolant, nor the original factory high-voltage frequency-conversion circulation pump, nor the original pipeline pressure parameters and flow rate descriptions.

He didn't even know what kind of ultra-large-scale thermal management network PMCU-17 was hooked up to back then, whether it was single-phase liquid cooling or two-phase immersion type.

All he could do was conduct conservative reverse estimations based on the first law of thermodynamics and the fundamentals of fluid mechanics.

First, measure the Physics diameter of the fracture, and analyze the compressive strength limit of the inner wall material of the residual pipeline.

Then use external low-power flexible heating films to perform partitioned thermal excitation on the shell, use an infrared thermal imager to record the thermal diffusion path, draw the three-dimensional heat conduction distribution map of the whole machine, and estimate the safe range little by little.

If the pump was too strong, it would wash out and break the residual pipelines.

If the pump was too weak, cooling would be meaningless.

If the pressure fluctuation was too large, it would trigger unknown hardware protection.

Facing this rigorous thermodynamic demand, Jiang Lin had to frequently go out to explore and search for usable resources.

Precisely because he had the motorcycle, drone, and G-Explorer-B, he was able to expand his search range beyond a hundred kilometers.

In the spring of the twentieth year, he dug out a rust-covered heavy industrial hydraulic pump in a buried underground mining station site in the west.

This thing was originally used to provide circulating pressure for shield tunneling machines; although bulky, that crude mechanical structure still maintained basic functions over thousands of years.

He disassembled and de-rusted the hydraulic pump, replaced it with a homemade sealing ring, and used it as the main circulation power for the cooling bypass system.

In the summer of the twentieth year, while conducting conventional map surveying a hundred kilometers away to the northeast, he discovered an abandoned deep geothermal well.

Inside, he found some silicon-based synthetic fluid.

...

Just like this, by scavenging, Jiang Lin spent nearly three years and finally pieced together a cooling bypass system using the mining station's hydraulic pump, industrial robot hydraulic servo valves, and silicon-based synthetic fluid.

This thing was ugly and heavy, emitting a tractor-like low-frequency roar when operating.

But solidly and truly, it built a firewall for PMCU-17 to welcome its first wake-up response.

...

Winter of the twenty-third year.

Everything was ready.

The external cooling bypass pressure indicator light remained constantly green, and the flow rate was stable.

The temperature change rate at various monitoring points on the shell was tightly suppressed below the safety threshold.

The micro contact resistance of the maintenance interface was maintained at an extremely low and stable state.

Jiang Lin took a deep breath and pushed down the switch.

The transformer of the low-voltage isolated power supply module emitted an extremely subtle high-frequency oscillation sound, beginning to output the first-tier wake-up voltage to the PMCU-17.

One second.

Three seconds.

Five seconds.

No response.

Seven seconds.

The pointer of the ammeter showed an extremely slight jump, indicating that some high-impedance circuit inside had been successfully activated.

Suddenly, on the screen of the data terminal connected to the diagnostic interface, a green strobe flashed past.

Immediately following, a long string of characters mixed with a large amount of hexadecimal garbled text jumped out from the bottom of the screen.

Jiang Lin's finger hovered over the emergency power-off knife switch without moving.

Twelve seconds later, the power supply module sensed that the impedance of the internal circuit was rising sharply, and automatically cut off the output to prevent burn-through.

The ammeter returned to zero.

But on the terminal screen, a few lines of cold and clear plain text information were left behind.

[System bootstrapping...]

[PMCU-17 emergency diagnostics layer activated]

[Core logic unit access: Denied]

[Local log offline cache: Sectors partially readable]

[Environmental thermal circulation system: Severe failure]

[Internal maintenance bus status: Operating in degraded mode]

[Main array optical communication link: Physics lost]

[Global clock verification...]

[Last network synchronization time: November 3, 2096, 04:17:22]

Jiang Lin did not immediately touch these offline logs.

What could be read out under this damaged state could not possibly be data left by ordinary flash memory.

That was more like a radiation-hardened non-volatile storage array.

Most verification blocks had failed; only the maintenance logs protected by multiple error-correcting codes could still be read out in the form of fragments.

In other words, these few lines of words on the screen were not the awakening of a complete system.

They were merely the last few twitches remaining from the nerve endings after a behemoth had died for many years.

Jiang Lin stood in front of the screen, gazing at these few lines of text, silent for a long time.

These brief system feedbacks, like several thunderclaps, unraveled many mysteries that he had once puzzled over.

First, beneath the collapse zone, there indeed existed a grand-scale regional subterranean computing array.

Second, this PMCU-17 dug out with so much effort was merely the outermost and most marginal maintenance nerve ending in that behemoth system.

Third, this incredible system had at least once possessed a complete local diagnostic error-correction capability, a massive log caching mechanism, an independent thermal cycle monitoring system, a degraded maintenance bus, and a main array link leading to some core.

However, what truly surprised Jiang Lin was the last line of words.

Last synchronization time: [November 3, 2096].

If this string of numbers was merely a code identifier for some internal system cycle, it would be easy to explain.

But if this was a timestamp marker similar to the Common Era of the Real World, then the last networked operation time of this massive subterranean system was actually more than seventy years later than the Real World he knew.