MiniCPM Family (OpenBMB)
The course's on-ramp hero: a family of small, genuinely-open models (MiniCPM5-1B, 3-4B, V 4.6, o 4.5) from Tsinghua + ModelBest, with the Ultra* datasets, Apache-2.0, and first-party fine-tuning via SWIFT and LLaMA-Factory.
MiniCPM is the course's default base because it is small, open, and license-free. MiniCPM5-1B (1.08B, Intelligence Index 17.9) fine-tunes in minutes on a consumer GPU — demonstrable proof of the FT00 thesis (steering, not teaching). Apache-2.0 with no MAU or field-of-use clauses means students can ship without license friction.
The family spans the modality axis, not a capability axis. MiniCPM5-1B (text) → MiniCPM3-4B (denser text) → MiniCPM-V 4.6 (+ SigLip-400M vision encoder) → MiniCPM-o 4.5 (omni, full-duplex). Each step adds a modality or capability the previous lacked; SigLip-400M is the load-bearing component that turns a text base into a vision-language model.
The Ultra* datasets (UltraChat, UltraFeedback arXiv:2310.01377, Ultra-FineWeb) are the course's data reference, not just MiniCPM's model reference. They are open, documented, and reproducible — so the course can point at a concrete preference pair and say 'this is the signal DPO optimizes.' A closed dataset cannot match this as a teaching tool.
SWIFT vs LLaMA-Factory is decided by modality, not preference. Text models (5-1B, 3-4B) produce equivalent results in both. Vision (V) and omni-modal (o) favor SWIFT — ModelBest/OpenBMB's first-party framework — for native modality handling, first-party chat templates, and example scripts maintained by the people who built the model.