Reborn not to be a beast of burden, I set the rules.

Let's turn back time a little.

When Ye Ming carried tea and fruit into the Computer Science Department's office building, Shen Zhiyi was sitting in the Information Science Department's laboratory.

Sunlight streamed in through the window, illuminating her profile and making her pale skin appear almost transparent.

She lowered her head, her long hair hanging down to cover half of her face, revealing only the line of her nose.

He was wearing a white long-sleeved shirt with the cuffs rolled up twice, and he was leaning over the table writing something, the pen nib making a scratching sound.

Next to it is the SEP6200 development board, and there is a faint scent of pine in the air.

She finished writing the last word and put down her pen.

The door was pushed open. Shi Xinglong walked in. He was in his early fifties, with slightly disheveled hair, shirt sleeves rolled up to his elbows, and carrying an enamel mug. He had been at the School of Information Science and Technology for twenty years and was a senior professor specializing in embedded systems.

"Is the list ready?"

Shen Zhiyi raised her head, tucked her stray hair behind her ear, and handed over the paper.

Shi Xinglong took it and glanced at it. 256MB RAM, 2GB Flash, 3.5-inch screen, capacitive touchscreen. He pulled up a chair and sat down.

"How should the system layer be configured when running Android on the SEP6200?"

"Delete WiFi, Bluetooth, GPS, multitasking, and animations. Reduce system services from thirty to fifteen, and compress it to under 100MB."

"What about the HAL layer?"

"Deleted WiFi and completely removed the HAL module. Commented out the dependent services in init.rc."

"BlueZ protocol stack?"

"Cut them out. Delete all the drivers; they're useless."

Shi Xinglong picked up his cup and took a sip: "What about the startup speed?"

"From power-on to booting to the desktop, it takes about forty to fifty seconds. By trimming the kernel driver and changing the init script from serial to parallel, we can save a few seconds. Adding a boot animation makes users feel like they're not waiting."

"Core services will be loaded on demand. SurfaceFlinger and similar services will only launch when the user actually needs them. This saves ten seconds, but the first time the application is opened, it will lag slightly."

Shen Zhiyi thought for a moment: "This phone is mainly used for browsing the browser and viewing documents. Users can accept that the browser might lag a little the first time it starts."

Shi Xinglong flipped through the list, pointing to the line "256MB RAM": "Should we adjust the Dalvik virtual machine settings?"

"Adjust. Increase the heap memory limit; we need to test how much to increase it by."

"GC frequency will change."

"A larger heap memory reduces the number of garbage collection (GC) cycles, but each GC cycle takes longer. It can't be set too high; a balance needs to be found."

Shi Xinglong glanced at her: "When did you look at the Dalvik documentation?"

"Last week, the HeapSource.cpp file in the source code contained comments explaining the heap memory configuration logic."

Shi Xinglong didn't ask any more questions. He stood up, pushed the list back to her, and stopped at the door.

What's the problem with replacing RAM?

Shen Zhiyi said, "BGA packaging carries a high risk of soldering issues. After the replacement, the bootloader will need to have its memory configuration changed."

Shi Xinglong waited a few seconds: "That's all?"

Shen Zhiyi didn't say anything.

"How much should the address mapping be expanded? How should the SDRC register be configured? Do the timing parameters need to be adjusted?" He looked at her. "Your board uses Hynix chips, which are different from Samsung's reference design. What is the CAS latency of Hynix? What happens if it's configured incorrectly?"

Shen Zhiyi didn't respond.

Shi Xinglong, holding his cup, didn't turn around: "The timing parameters are on pages 782 to 798. Hynix's CAS is 3, Samsung's is 2. It's misconfigured. The board can power on, the serial port has output, but the memory initialization fails." He paused for a moment, "Go back and look through the datasheet, figure these things out before you start."

He took two steps, then stopped: "There's another problem. You've upgraded to 256MB of RAM, which increases the physical address space, but the SEP6200's TLB is fixed. A larger page table means more TLB misses. Have you calculated the overhead?"

Shen Zhiyi didn't say anything.

"Never thought about it?"

"I haven't thought about it."

"The metal cabinet in the corner, second shelf, ARM Architecture Reference Manual. Turn to the TLB chapter." He picked up his cup and left. "Come find me again when you've figured it out."

The door closed.

The lab fell silent. Shen Zhiyi turned to page 782 of the SEP6200 datasheet; CAS Latency = 3.

She folded a corner, walked to the corner of the wall, opened the metal cabinet, found the ARM Architecture Reference Manual on the second shelf, turned to the TLB chapter, and slipped a sticky note inside.

She stuffed both handbooks into her bag and folded the list inside. Reaching the door, she glanced back at her computer screen; almost half of the Android 1.6 source code had been downloaded.

She closed the door, walked out of the laboratory building, and headed towards Zhujiang Road. Sunlight fell on her shoulders, and her pace quickened compared to when she arrived.

At 10:30, Ye Ming pushed open the door to the computer room.

He carried his laptop bag, his shoulders slumping slightly. His face was expressionless, but not in its usual calm; he seemed lost in thought, not quite out of it yet.

Li Yue saw him first and stopped typing: "Oh, you're back? What did Teacher Zhang say?"

Ye Ming placed his bag on his desk, unzipped it, took out his notebook, and set it aside: "I've talked quite a bit; I'll elaborate later."

Ruan Xing peeked out from the corner, her shoulder-length hair a little messy, probably from rubbing it while she was writing. She called out "Classmate," her eyes crinkling into crescents, her lips curving upwards to reveal a hint of her canine teeth. Ye Ming smiled and nodded at her.

His gaze swept over Xu Wei.

Today, she tied up her long, wavy hair, straightening most of the waves except for the curls at the ends, which stick up in an arc like a cat's tail that hasn't woken up yet. A few short, curly strands of hair couldn't be hidden at her temples, sliding down from behind her ears and clinging to her jawline, curving in a crooked way.

She was wearing a gray sweatshirt, her hair was casually tied up, her face was a little paler than usual, her lips were also pale, and there was a faint bluish tint under her eyes, like a flower wet with morning dew.

When Ye Ming's gaze swept over her, she didn't look up; her fingers rested on the keyboard, remaining motionless for a long time.

Didn't sleep well last night?

He remembered the incident he had just seen on Teacher Zhang's computer, stood up, poured a glass of warm water, and placed it beside her.

Xu Wei's fingers paused for a moment. She didn't look up. After a few seconds, she reached for the cup, picked it up, and took a sip. It was lukewarm. She put the cup back and continued proofreading. The sound of her fingers tapping on the keyboard quickened slightly.

Ruan Xing saw Ye Ming pouring water for Xu Wei from behind. Before retreating, she said to Ye Ming, "Sister Xu Wei is here very early today."

After saying that, he turned back to stare at the screen, his lips still slightly upturned, but the smile had frozen on his face.

She typed with her head down, typed a few lines and then deleted them, typed again and deleted again.

Her shoulder-length, tousled hair fell down, obscuring half of her face and making her expression impossible to discern.

Li Yue leaned back in her chair, looked at Ye Ming, then at Xu Wei, and smiled: "Ye Ming, you come back and immediately pour water, did Teacher Zhang teach you that?"

Ye Ming said, "Teacher Zhang teaches techniques."

"I've never seen you pour water for your senior, even though it's technical stuff," Li Yue said.

Zhang Yuan didn't even look up, his fingers never stopping, as if he hadn't heard a thing. Lin Zhixia looked up and smiled at Ye Ming: "You're back?" Ye Ming nodded.

Li Yue glanced at her phone: "Lin Ting will be here soon. He just messaged me saying he's already left. Since you're back, let's take a look at the UI design together."

Ye Ming responded and flipped out a few pages of notes he had taken earlier, on which were drawn several simple interface sketches.

He had thought about the UI design beforehand, and today he happened to meet with Lin Ting to discuss it.

Just then, the door was pushed open.