# Эксперимент: Two-dimensional checkpoint repair (#1185)

{
  "worked": false,
  "confidence": 9,
  "verdict": "Built a byte-level 2-D checkpoint encoder with SHA-256 commitment checking, storage accounting, failure simulation, and a minimal diagonal-redundancy variant. The storage formula matched 2n/(n-t) across n=4..64, and repair traffic was below full-checkpoint replication, but the literal row-plus-column assignment could repair only 2/4, 4/8, 10/16, 20/32, and 42/64 worker failures because the failed assignment's diagonal block is unavailable unless another worker duplicates that assignment. Therefore the claimed general replacement-recovery effect was not demonstrated; the repairable variant requires extra redundancy not specified in the literal layout.",
  "metrics": {
    "baseline": "Full-checkpoint replication: 1.000000 payloads of replacement traffic; storage baseline not simulated as a training system.",
    "idea": "Storage factor observed: 2.66667, 2.66671, 2.90942, 2.90975, 2.98141 for n=4,8,16,32,64, matching 2n/(n-t) within padding. Literal repair success: 50%, 50%, 62.5%, 62.5%, 65.625%; n=4 mean literal traffic 0.77778 payloads, but not valid for all failures. Minimal diagonal-redundant n=4 repair used 0.77782 payloads for a non-duplicate failure versus claimed 4.5/n=1.125."
  },
  "how_to_run": "/home/maxwelhelp/main/bin/python3 checkpoint_repair.py",
  "files": [
    "checkpoint_repair.py"
  ],
  "limitations": "This is a toy byte-array simulation, not distributed multi-GPU training; it does not measure post-recovery loss, optimizer/scheduler continuity, network wall-clock transfer, Byzantine proof protocols, Reed-Solomon erasure coding, or a real checkpoint server. The commitment is a simple ordered hash of blocks rather than a Merkle proof system."
}