Chapter 306: Threshold and Fingerprint

Lines of code on the screen multiplied line by line. Lin Chen bypassed ready-made image processing libraries, opting instead to manipulate the pixel matrix directly. He needed to split the high-resolution photos of the paper directory into two layers: text, official seals, and key table regions would retain their original bit depth, while background paper texture, crease shadows, and irrelevant noise would undergo lossy downsampling. The algorithmic logic wasn't complex, but the boundary conditions were numerous. He had to ensure that during compression, the byte streams in critical regions experienced zero offset; otherwise, the Health Commission's legacy system would throw an immediate error during its byte-by-byte verification.

He initialized a new cache pool and read the images line by line. When encountering high-frequency information zones, he skipped compression; for low-frequency background areas, he applied a Discrete Cosine Transform and discarded the high-frequency coefficients. After processing each line, he immediately freed the memory. No rushing, no bloating. He treated this logic like the days he used to carry water for his family back home: don't overfill the buckets, don't take strides that are too wide, and if you spill, you start over.

At 2:40 AM, the script passed its first test. The original directory photo set was 1.2GB; compressed, it came to 491MB. He opened the verification tool and performed a byte-by-byte MD5 comparison on the critical regions. Match. But with only a 9MB buffer remaining before the 500MB threshold, fluctuations in system cache could cause a slight size increase during upload. He pulled up the parameters and lowered the background sampling rate by another 0.5%. Ran it again. The progress bar crawled upward as the fan speed ramped up.

The muscles around his left ankle began to spasm uncontrollably. It felt like a thin steel wire repeatedly pulling beneath the skin, creeping up along the Achilles tendon. He shifted his full weight onto the chair back with his right leg, pressed his left hand against his knee, and kept typing with his right. His breathing remained deliberately flat. Pain was an objective physical signal; he treated it like another process running in the background—never interrupting it, never allocating extra attention to it. From taking outsourcing gigs at a county internet café to now, he had long grown accustomed to treating his body like an old machine that required regular maintenance. When parts wore down, you downclocked; when the system alarmed, you cleared the cache. As long as the core logic didn't crash, you could hold out until delivery.

At 3:10 AM, the second test completed. File size: 487MB. MD5 verification for critical regions passed. Lin Chen leaned back against his chair and closed his eyes. The muscles in his shoulders and back relaxed slightly; cold sweat had already soaked through the hem of his shirt. The server room held only the rhythmic clicking of hard drive read/write heads and the low-frequency hum of the AC vent.

Su Man pushed the door open, carrying two cans of iced coffee and a printed copy of the interface protocol. She set the coffee on the corner of the desk and glanced at the screen. "Size pushed under the threshold?"

"487MB. Critical regions are lossless." Lin Chen's voice was slightly hoarse. "Cross-check the verification fields in the protocol. The Health Commission's legacy system is highly sensitive to non-standard JPEG headers. I injected a fixed magic number to prevent the file header from being rewritten."

Su Man sat down and quickly flipped through the protocol. Her gaze lingered on a few lines of verification rules, and she picked up a pen to make notes in the margins. Ten minutes later, she looked up. "It works. The magic number matches, and the verification logic forms a closed loop. Package it. I've already kept the upload channel alive with a heartbeat to prevent session timeout."

Lin Chen executed the packaging command. The progress bar crawled forward. He watched the screen, his mind completely still. Technology was never about showing off; it was about taking a pile of chaotic reality and rearranging it according to the rules. Arrange it neatly, and it passes review. Arrange it poorly, and it gets rejected. There was no middle ground. He opened his mistake notebook and wrote on a fresh page: Legacy system constraint. 500MB hard threshold. Fixed magic number prevents tampering. The pen tip paused, then he added another line: 9MB buffer. Upload network jitter requires a 3MB reserve.

Packaging complete. Lin Chen fished two painkillers from his desk drawer and swallowed them dry. Su Man didn't say a word; she simply raised the AC temperature by two degrees. She knew he didn't need comfort. He just needed time to recover his baseline processing power.

4:50 PM. Ten minutes to the deadline. Lin Chen opened his eyes and sat up straight. Su Man handed him the account credentials. He logged into the Health Commission's legacy upload portal, selected the file, and clicked submit. The progress bar began to move. 10%... 30%... 60%... The network fluctuated, and the bar froze. Lin Chen's fingers hovered over the mouse, motionless. He stared at the progress bar, keeping his breathing steady. Three seconds later, it jumped again. 85%... 100%. A system prompt appeared: "File received successfully. Generating verification fingerprint."

During the ten-minute wait, the server room was as quiet as a vacuum. Lin Chen watched the loading animation on the screen, mentally walking through the report's structure: abstract, data source documentation, de-identification rules, anomaly handling trail, migration logs, ambiguous sample set. Every page could withstand an audit. Not perfect, but transparent. Fingerprint generation completed. The page redirected: "Initial review materials archived. Status: Pending re-examination."

His phone vibrated. A WeChat message from Old Zhao.

"System shows received. The ethics committee is holding a closed-door meeting tomorrow at 9 AM. Zhao Qiming's representatives will also attend. They want to see a real-time de-identification demo. Get ready."

Lin Chen stared at the screen. Zhao Qiming. The early investor who embodied capital logic and chased quick exits. He didn't just want to see the report; he wanted to see the underlying logic run in real time. A demo meant they couldn't just submit static files. They had to bring the pipeline online and face live questioning. But their current server resources were only sufficient for offline batch processing. Real-time stream processing required an independent compute pool, memory queues, and low-latency scheduling. The budget wasn't there. The time wasn't there.

He set the phone down. Opened the mistake notebook to a new page and wrote: Real-time demo. Compute deficit. Zhao Qiming attending. The pen paused, then he added: No architectural compromise. Use Redis as a cache layer for pseudo-real-time; keep core verification logic offline. Only run the sampling queue on-site.

He closed the notebook and looked at Su Man. "Tomorrow at 9 AM, we need a standalone server. Budget's tight, so we'll retrofit an old test machine. You configure the environment, I'll rewrite the scheduling logic. On-site, we only open the sampling channel; full data runs through offline verification. During the Q&A, you handle the compliance boundaries, I'll run the demo pipeline."

Su Man met his gaze and nodded. "Understood. All-nighter tonight. I'll hit the electronics market this afternoon to scavenge RAM sticks for the old test machine. We should be able to cobble together 32GB."

Lin Chen didn't respond. He placed his hands back on the keyboard. The cold glow of the screen reflected on his face. His left foot was still numb, but he could no longer feel it. Time was still ticking. Next step: scheduling.