From the stray current Edison found in a light bulb to a switch that steers electrons on command — vacuum tube, PN junction, transistor, the short history of taming electricity.

A circuit that can remember a single 0 or 1, grown step by step into a register — and why cache, not clock speed, is what makes a gaming CPU fast.

Hard drives store with magnetism, SSDs trap electrons in an insulator, RAID trades extra disks for reliability — plus the truth behind that scary "RAID 5 rebuild fails 99% of the time."

Main memory and video memory came from the same place and then split — one obsesses over latency, the other over bandwidth, and HBM ends up bolting memory onto the GPU's roof.

Light is both the chisel that carves chips (lithography) and the paint that makes screens (quantum dots, AR waveguides) — how humans learned to tame it in the space of a silicon chip.

When a wall gets this expensive, the industry attacks it from every side — tier through NAND, pool over CXL, ditch HBM, compute inside memory. None of them breaks the wall in 2026. Which tells you exactly where this cycle's turn is not going to come from.

Memory is the most cyclical business in tech — 40 years of up-10x, down-90%. This run has three genuinely structural differences. But 'this time is different' is the most expensive sentence in finance, so the bear case gets equal weight.

HBM isn't faster DRAM. It's DRAM rotated 90 degrees — stacked, drilled through with thousands of vertical wires, and bolted next to the GPU on a silicon interposer. That manufacturing nightmare is exactly why three memory makers just crossed a trillion dollars.

The same chip lives in your USB stick, your phone, and the petabyte SSDs feeding AI clusters. It got cheap by trading endurance for density — and that exact tradeoff is why AI is now dragging it out of cold storage and onto the hot path.

DRAM is a leaky bucket you refill thousands of times a second. That physical fragility is why it's fast, why it's volatile, and why it just hit a scaling wall at the exact moment AI demand exploded — sending RAM prices up triple digits.

I finance the machines AI runs on, and the single priciest, scarcest part inside the box isn't the logic die — it's the memory stacked next to it. This is why: inside a modern accelerator, raw FLOPS stopped being the binding constraint. Memory bandwidth did.

听了一位前谷歌 TPU 工程师的深度访谈，终于理解了 TPU 和 GPU 不是同一道题。一个是通用性之王，一个是定制化之刃。Apple、Anthropic、Meta 都在用 TPU 了——这不是替代，是生态在裂变。

A former Google TPU engineer who worked on V7 and V8 revealed how TPU actually competes with Nvidia. The answer isn't about chip specs — it's about system-level design, software co-optimization, and a fundamentally different philosophy. Apple, Anthropic, and Meta are all using TPU now. Here's what that means.