Path to Staff Engineer

Path to Staff Engineer

Everything a Senior Engineer Needs to Know About What's Inside an LLM

Learn what AI models are made of

Sidwyn Koh's avatar
Sidwyn Koh
Jun 20, 2026
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Welcome back to Path to Staff! This series is a little different from our usual programming. In this series, we’re covering LLMs and AI in-depth.

As an engineer, I never really had the time to understand AI’s internals. But I’ve spent the past few weeks doing deep research to unpack it all.

As a reminder, this is Part Two of a five-part series:

  1. The Hardware Behind AI – And How It’s Programmed. Transistors, semiconductors, and fabricators. Learn about the big players (TSMC, Nvidia, ASML). The memory-compute bottleneck. And all the acronyms you always wondered about (TPU, ASIC, FPGA, CUDA, etc.)

  2. Model Architecture. (We are here.) Learn about what models are made of. We’ll cover the paper that started it all (”Attention is All You Need”), plus talk about transformers and diffusion models.

  3. Training. The meat of teaching a model. How does pretraining work? What goes into it (backpropagation, optimizers, loss functions)? What scaling laws should we weigh before we kick off an expensive training …

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