Content addressing operates on any byte sequence regardless of semantics

A common objection to applying Tier 3 to scientific data: the protocols transport opaque byte streams, while scientific data carries provenance, metadata, and governance requirements those protocols were not designed for.

The objection conflates the storage substrate with the governance layers every preservation system has always built on top of it. Content addressing operates on any byte sequence regardless of its semantics. The hash of a FITS cube from a radio telescope, an fMRI volume, a CSV of field measurements, or a Git commit is computed the same way; identity, integrity, and deduplication behave identically across content types. Signed repositories (Git commit signing, Git tag signing) establish provenance without requiring trust in the host, and the signature travels with the object.

The features scientific data requires above the byte-stream layer — curated metadata, versioning policy, dispute resolution, schema governance — are the same features every Tier 2 system already layers on top of Tier 1 storage. The Protein Data Bank's weekly synchronization, GenBank's Feature Table format, and the IVOA standards are each governance and metadata layers built above a storage substrate. The architectural question is not whether protocols can preserve scientific context. It is whether the storage substrate beneath those governance layers is architecturally fragile or structurally redundant.

Tier 3 is a foundation layer, not a complete solution. The layering principle that has made Tier 2 successful on top of Tier 1 operates equally on top of Tier 3.