What is on a storage port (v4/system/storage.c): it takes Block read,
Block write and Block data and answers Block data or Block done. It
holds a view of a common chain, a private chain, or both; private block k
is number 2^32 - 1 - k. Behind it is v3's block subsystem, reached
through v4/system/store_v3.c, the one v4 file that includes v3's headers.
v3's block code links here with its two device back ends, its log and
its clock, and nothing else of v3.
v4/tests/test_store.c: 36 checks at 64 bits, 35 at 32, and under the
sanitizers. docs/v4.0.0/MESH.md 8.3, 8.4.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
