From d397a1ee34aafd742ba327ad02279a6f783bcb5f Mon Sep 17 00:00:00 2001 From: ReaperOfVeriod Date: Sun, 11 Oct 2026 03:31:31 +0200 Subject: [PATCH] Differential analysis finds no constant substructure at stride 368 Range measured: level 0, 16047040..16737344. 1875 whole 368-byte records from the region start, variation checked across the first 60. Method: the differential analysis that identified the shrub body -- compare records byte by byte, record which positions differ. Result: all 368 positions vary. No constant field, no padding, no header inside a record. The shrub body separated immediately into a varying payload and a constant two-byte tail; this format has nothing constant to separate. That is consistent with the autocorrelation peak rather than in tension with it. Checking which positions carry the 368-stride matches over 20000 positions gives 168 exact 4-byte repeats, distributed evenly at 0.84% across all four byte offsets. Whole 4-byte sequences recur at exactly 368 while no individual position is constant -- consistent with records containing entries that repeat at a fixed relative index, not with a fixed-layout record. So the 368 stride stands and the records stay unidentified. Worth recording that the shrub method failed here for a specific and predictable reason: it needs something constant to latch onto. Applying a method that worked elsewhere is not the same as it applying here, and saying so is cheaper than the next person assuming the technique transfers. --- docs/formats/core-data-regions.md | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/docs/formats/core-data-regions.md b/docs/formats/core-data-regions.md index 10085d1..3491bde 100644 --- a/docs/formats/core-data-regions.md +++ b/docs/formats/core-data-regions.md @@ -218,3 +218,27 @@ of that level's data, but 24 of 24 agreeing is a format invariant. What a 368-byte record *is* remains unestablished. This is the same position the shrub body was in before differential analysis identified its records, and the same method is the obvious next step. + +### Differential analysis at stride 368: no constant substructure + +**Range measured:** level 0, `16047040 .. 16737344`. 1,875 whole 368-byte +records from the region start; variation checked across the first 60. + +**Method:** the same differential analysis that identified the shrub body -- +compare records byte by byte and record which positions differ. + +**Result:** **all 368 positions vary.** There is no constant field, no padding +and no header inside a record. Unlike the shrub body, where differential +analysis immediately separated a varying payload from a constant two-byte +tail, this format has nothing constant to separate. + +That does not contradict the autocorrelation peak. Checking which byte +positions carry the 368-stride matches over 20,000 positions: 168 exact 4-byte +repeats, distributed evenly at 0.84% across all four byte offsets. So whole +4-byte sequences recur at exactly 368 while no individual position is constant +-- consistent with records containing entries that repeat at a fixed relative +index, rather than with a fixed-layout record. + +**So the 368 stride stands and the records remain unidentified.** The shrub +method failed here not because it was the wrong tool but because it needs +something constant to latch onto, and there is nothing.