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ADR-026 — Bit-packing layout

  • Identifier: ADR-026
  • Title: Bit-packing layout
  • Status: Accepted
  • Source: extracted verbatim from the Engineering PRD, docs/prd/08-kernel-design.md (REQ-DOC-004). From M0 onward this file is the canonical, living ADR record; status changes happen here and in the index, with the PRD text remaining the historical record.

  • ADR-026 — Bit-packing layout. Status: Accepted. Problem: fix the packed layout. Alternatives: MSB-first (rejected: no ecosystem pull), 32-value lane-interleaved FastLanes layout (rejected for v1: ties Quiver to an evolving format — Charter §8.1 defers compressed-format coupling), LSB-first little-endian contiguous (selected): value i occupies bits [i·w, (i+1)·w); bit j lives at byte j/8, bit j%8. Parquet-RLE-bit-packing-compatible, trivially specifiable, byte-order-independent definition. Reconsideration: v2 compressed-kernel expansion may add interleaved layouts as new APIs. Related: REQ-K8-001.