{
  "schemaVersion": 1,
  "modelVersion": 1,
  "generatedAt": "2026-10-21T10:54:34.174Z",
  "evidenceType": "Constructed byte-accounting examples; not device observations or paper replication",
  "license": "CC0-1.0",
  "units": {
    "bytes": "bytes",
    "KiB": 1024,
    "byteWaf": "disk-written bytes / host-written bytes"
  },
  "assumptions": [
    "One positive host update, written exactly once.",
    "Two supplied affected-valid-byte counts; zero means no data to preserve on that side.",
    "Memory case reads each protected byte once and rewrites it once.",
    "Disk-backup case additionally writes each protected byte to a safe backup region and reads it back once.",
    "Backup-region writes cause no recursive overlap; modeled transfers complete successfully.",
    "Metadata, read-modify-write of untouched target bytes, cache eviction, retries, synchronization cost and crash recovery are excluded.",
    "Byte ratios do not count commands, rotations, time or durability; there is no sampled population or confidence interval."
  ],
  "sources": [
    {
      "url": "https://www.usenix.org/system/files/conference/hotstorage18/hotstorage18-paper-wu.pdf",
      "scope": "Sections 1 and 3: overlap mechanism and byte-based WA definition."
    },
    {
      "url": "https://www.usenix.org/system/files/atc21-liang.pdf",
      "scope": "Section 3.3: backup-region sequence, distinct from our simplified accounting."
    },
    {
      "url": "https://arxiv.org/pdf/2206.14368v1",
      "scope": "Section 2.1: memory-backed preservation; no crash-equivalence inferred."
    }
  ],
  "sha256": {
    "imr-accounting.mjs": "7ceb22c566f3bbacc86601dadd4a5eb0f9c2d99e38988850fd6ba2d20d415e1d",
    "imr-accounting.test.mjs": "9f2b7c89f9eb1b8692974a17675156338f06a8fe84eaf38996480f645289ab70",
    "build-imr-accounting.mjs": "d15a51295e64b8511913525a8d062b206371007ded977050ede472cec797c3c9"
  },
  "rows": [
    {
      "scenario": "No affected valid data",
      "hostBytes": 4096,
      "neighborBytes": [
        0,
        0
      ],
      "backup": "memory",
      "protectedBytes": 0,
      "backupReadBytes": 0,
      "backupWriteBytes": 0,
      "diskReadBytes": 0,
      "diskWriteBytes": 4096,
      "totalDiskBytes": 4096,
      "byteWaf": 1,
      "totalTransferRatio": 1
    },
    {
      "scenario": "One 4 KiB neighbor",
      "hostBytes": 4096,
      "neighborBytes": [
        4096,
        0
      ],
      "backup": "memory",
      "protectedBytes": 4096,
      "backupReadBytes": 0,
      "backupWriteBytes": 0,
      "diskReadBytes": 4096,
      "diskWriteBytes": 8192,
      "totalDiskBytes": 12288,
      "byteWaf": 2,
      "totalTransferRatio": 3
    },
    {
      "scenario": "Two 4 KiB neighbors",
      "hostBytes": 4096,
      "neighborBytes": [
        4096,
        4096
      ],
      "backup": "memory",
      "protectedBytes": 8192,
      "backupReadBytes": 0,
      "backupWriteBytes": 0,
      "diskReadBytes": 8192,
      "diskWriteBytes": 12288,
      "totalDiskBytes": 20480,
      "byteWaf": 3,
      "totalTransferRatio": 5
    },
    {
      "scenario": "Same data, disk backup",
      "hostBytes": 4096,
      "neighborBytes": [
        4096,
        4096
      ],
      "backup": "disk",
      "protectedBytes": 8192,
      "backupReadBytes": 8192,
      "backupWriteBytes": 8192,
      "diskReadBytes": 16384,
      "diskWriteBytes": 20480,
      "totalDiskBytes": 36864,
      "byteWaf": 5,
      "totalTransferRatio": 9
    },
    {
      "scenario": "Larger preservation units",
      "hostBytes": 4096,
      "neighborBytes": [
        16384,
        16384
      ],
      "backup": "disk",
      "protectedBytes": 32768,
      "backupReadBytes": 32768,
      "backupWriteBytes": 32768,
      "diskReadBytes": 65536,
      "diskWriteBytes": 69632,
      "totalDiskBytes": 135168,
      "byteWaf": 17,
      "totalTransferRatio": 33
    },
    {
      "scenario": "Larger host payload",
      "hostBytes": 16384,
      "neighborBytes": [
        4096,
        4096
      ],
      "backup": "disk",
      "protectedBytes": 8192,
      "backupReadBytes": 8192,
      "backupWriteBytes": 8192,
      "diskReadBytes": 16384,
      "diskWriteBytes": 32768,
      "totalDiskBytes": 49152,
      "byteWaf": 2,
      "totalTransferRatio": 3
    }
  ]
}