# Cluster environment backups

Per-cluster runtimes for Qwen3.5 / Nemotron post-training. Public on purpose:
these are recipes and build artifacts, no credentials.

Each cluster directory holds `manifest.json` (python, torch, CUDA, driver, GPU,
`torch.cuda.get_arch_list()`), `pip-freeze-*.txt`, the build scripts, and any
expensively-built CUDA extensions under `overlays/`.

## Arch compatibility, measured

b200 is compute capability 10.0, b300 is 10.3. Neither cluster's torch lists
`sm_103`, yet a torch built for `sm_100` runs correctly on a B300: matmul,
transformer-engine Linear and causal_conv1d CUDA ops were all verified on a
B300 SXM6. Blackwell `sm_103` is binary compatible with `sm_100` cubins, so
these artifacts are portable across b200 and b300.

## Overlay rule

Install overlays with `pip install --target ... --no-deps` and prepend to
PYTHONPATH. Without `--no-deps`, pip drags PyPI torch and triton into the
overlay and silently shadows the cluster runtime.