2026-10-10-unimem-block-access.md

Raw Block access and Metal import contracts

Execution receipt, 2026-10-10. Source is frozen and native/dependent gates are complete. CODE review conditionally approved the source with one precommit requirement: preserve the moved historical material in the repository in this same unit. This audit supplies that requirement; its exact snippets and link target are checked before staging with the source. No compatibility approval is claimed.

Parent Honeycrisp 7b148906263da5ea8aabc5ddb0e2e44ff2288ecc, sibling Strata 56aedb2d12b3126c601eb333419136d403614dbb. The source manifest, SHA 1ead683ed4e75cfb0c2edd196e6e18e979f3ca83634e69c3bcdd2bfe72e1b1be, pins every changed file. All results below use that overlay on the exact Git archives; the source freeze preserves its original observation time.

Six Block typed views require unsafe initialization/exclusion obligations; mutable views require an exclusive receiver. Warm keeps its fixed16KiB stride, and raw Metal imports require runtime page alignment, a single current VM region, retained backing and completion discipline. Constructors/allocation/drop remain unchanged. These boundaries do not establish global driver soundness, physical-address availability, permanent page pinning, native frame ownership or Kadek foundation row6 completion.

Fresh different-vendor PLAN v3 review returned APPROVE before implementation. The response retains earlier review corrections. CODE review examines all safety contracts, source, fixtures and both native and dependent evidence; no four-vendor council is claimed.

Historical IOSurface claims

The following text is preserved verbatim from git show 7b148906263da5ea8aabc5ddb0e2e44ff2288ecc:unimem/specs/README.md (full source SHA6475bd489d1d3a05f0cadc0dfa66b23fb8ea1dde81c19a8b5f175c40f5f4d01f). It is historical material moved out of the contract, not a new result. Inspection found the probe source, but no original raw output, machine, invocation or measurement revision supporting these numbers. Source-history import revision1d1b866d is not a run revision. The performance projection remains unverified. Current native probe evidence must be reported separately and cannot retroactively supply provenance for this text.

### Measured performance (from experiment)

| Size | Alloc | Write throughput | Read throughput |
|------|-------|-----------------|----------------|
| 4 KB | 18 us | 22.8 GB/s | 22.8 GB/s |
| 1 MB | 15 us | 23.6 GB/s | 23.5 GB/s |
| 16 MB | 17 us | 23.6 GB/s | 18.9 GB/s |
| 256 MB | 20 us | 23.1 GB/s | 19.5 GB/s |

Throughput measured with volatile u64, single thread, no SIMD. With NEON/AMX: 60-70+ GB/s expected.

| IOSurface: pinned, contiguous VM region, ~20us alloc, ~23 GB/s write | experiments/iosurface_probe |

The original full-source SHA metadata accidentally omitted its terminal newline when captured by Nushell. The old metadata and corrected metadata retain that history. The exact table and row bytes never changed. The initial source-freeze JSON deliberately references the old metadata SHA; it does not invalidate the unchanged source files.

Native validation

Native summary, commands and full receipts record compiler binaries, hashes, environment, source/lock identities, times and actual exits. Parent and candidate use matching Rustup 1.95.0 compiler/Cargo/Clippy binaries; negative diagnostic-code doctests use the actual nightly-2025-11-26 compiler and rustdoc. The native host is Mac16,5 arm64, macOS 26.4.1/25E253. No moving toolchain or dirty sibling is a build input.

Gate on frozen source	Observed result
`test --workspace --locked`	351 pass, 5 ignored; parent 336 pass/5 ignored. Delta is 3 native tests and 12 doctests; moved tests are not counted new.
`test -p unimem --release --locked`	66 pass, none ignored; includes all new access tests and existing creation/roundtrip targets.
Actual nightly unimem/aruminium doctests	14 compile-fail cases pass, including 12 new expected-code witnesses; 4 preexisting examples ignored.
Selected GPU raw/import and private ANE fixtures; vecadd/matmul examples	All exit 0; private ANE completion/visibility remains an explicit inherited assumption.
Selected library Clippy with `-D warnings -D clippy::missing_safety_doc`	Exit 0, no warnings; contract content independently reviewed.
Completing selected fixture lint with `-W warnings`	Exit 0; all 8 emitted preexisting warnings match the parent's complete diagnostic multiset.
Strict owning rustdoc, release workspace build, unimem build/bench and pipeline	All exit 0; existing output-name warnings retained. Bench output is evidence of execution, not a performance claim.
Whole-workspace fmt	Exit 1; same existing objc2.rs formatting output.
Whole-workspace strict Clippy	Exit 101; same 4 emitted acpu diagnostics, first duplicated attribute in gemm/mod.rs:1094. Later targets are masked.
Whole-workspace `-W` Clippy	Exit 101; reachable diagnostic sets differ with parallel compilation. New emitted warnings are source-verified preexisting; old unreported benchmark failures remain masked.
Explicit exact-parent unimem semver check	Exit 100: 202 checks, 200 pass/2 fail/58 skip; detects 7 unsafe additions and 4 exclusive-receiver changes.

The initial workspace semver invocation detects newly unsafe Gpu::wrap, then fails on duplicate historical manifests embedded in old audit snapshots. The explicit unimem command resolves that ambiguity and preserves the actual API breaks. Last-tag resolution separately fails on the unpinned historical nebu path; there is no successful tag-compatibility verdict. Semver scratch dependency resolution is separate from locked source build/test evidence. The native summary details every emitted-versus-masked finding and earlier tooling correction.

Dependent compatibility

Parent summary and candidate comparison identify the exact origin inputs and retained diagnostic locks. The machine-readable comparison and verification retain all 37 identical command pairs: 16 candidate exits are zero, 21 nonzero, including metadata gates.

Xena, Bita and Erga newly fail at changed unsafe or exclusive-receiver calls; some earlier errors are masked by these compile failures. Those are intentional API breaks requiring consumer migration, not preexisting failures. Perla's bounded GPU suite/oracle, Zoya release suite and Glia library suite still pass; Mir and Glia workspace failures remain. Missing origin locks, unavailable vendor closures and incomplete isolated Cyb closure are retained as separate limitations. Unchanged Nox evidence exercises the owning rung, not the driver API.

The masked-call inventory pins additional source paths that compilation did not reach. At Erga 848e17e, rs/rtable-bench/src/lib.rs:58 imports a Block; build_parallel(&self):76 requests mutable bytes at 80, and cpu_checksum(&self):106 reads at 107. Its CLI calls both at main.rs:52,111. The earlier blake-bench error masks these obligations. At Xena 6ea943a, xena-gpu/src/lib.rs:44–45 imports the caller-provided Block; xena-bench has CPU views in gpuverify at 44/58, gpubench at 22/75, cpugpu at 55, power at 147 and gpudebug at 171. Their GPU calls occur at 55, 35/85, 65, 158 and 182 respectively. Some mutable CPU views survive across submission and later CPU use; initialization, borrow scoping and owner lifetime require review, beyond merely repairing the first emitted error.

Complete stdout/stderr, commands, helper scripts, source inventories, lock evidence and their original hash manifests are retained compactly in parent payload and candidate payload. Each archive was extracted into a fresh directory and its entire SHA256SUMS verified. To inspect, extract an archive into an empty directory and run shasum -a 256 -c SHA256SUMS there. Readable summaries above are copies from those payloads. The native archive preserves full raw logs, including their original whitespace, and both native manifests verified after a fresh extraction.

Remaining work and authorization

No full-ring or zero-warning workspace claim follows. External migrations need initialization, retention, exclusion and completion proofs; mechanical unsafe annotations are insufficient. Safe native image ownership/accounting, fences, Grid/Buffer soundness and Kadek row 6 remain open. The physical-address/pinning semantic question is unresolved and its contract was not silently weakened.

This spec-touching, breaking source change requires decision classification; the owner's explicit audit/fix/merge instruction covers ordinary source work. Versions, sibling pins, tags and releases remain owner-controlled. Any commit while required global gates stay red uses wip: and quotes the first error. Original dirty worktrees under ~/cyber/honeycrisp and ~/cyber/kadek are preserved.