From 0ba790df1f463d3cac1db5278b626faee7253db4 Mon Sep 17 00:00:00 2001 From: ReaperOfVeriod Date: Sun, 11 Oct 2026 03:52:40 +0200 Subject: [PATCH] Correct the sky sub-object 0 live-byte figure; record the byte 7 anomaly The previous commit said "a mean of 6.99 of every 8 bytes are zero". That is inverted. 6.99 is the mean count of live bytes, and the records are nearly full rather than sparse. The live-byte histogram is 0:15, 2:1, 4:31, 5:238, 6:461, 7:1030, 8:1114. That error also invalidated the reasoning built on it in this session's next message, where the high zero-count was used to explain why the differential analysis found no constant positions. There was no zero-density to explain. The differential result stands -- all 8 positions vary -- but for the plain reason that the records are dense, not because of any artifact. New finding from re-examining it: byte 7 takes only 14 distinct values where bytes 0-6 take 142-204. Its common values are 0x00 (1378), 0xff (806) and 0x80 (592), which are the high bytes of signed 16-bit values. That is consistent with byte 7 being an MSB rather than ordinary data. Unexplained. Also tried and recorded as not helping: a signed 16-bit reading spans -32743..32633, near the full range, with no per-position structure (533, 371, 401 and 187 distinct at positions 0-3). --- docs/formats/core-data-regions.md | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/docs/formats/core-data-regions.md b/docs/formats/core-data-regions.md index 309f6bd..a56036e 100644 --- a/docs/formats/core-data-regions.md +++ b/docs/formats/core-data-regions.md @@ -368,15 +368,22 @@ statistics below. The matched-control autocorrelation puts the peak at stride **What it is made of:** - **1,185 distinct `u32` values** across 5,780 words. -- **Mean 6.99 of 8 bytes are zero**, so most records are sparse -- one or two - live bytes in eight. +- **Mean 6.99 of 8 bytes are live** -- the previous revision of this file said + "zero", which is inverted and wrong. The live-byte histogram is 0:15, 2:1, + 4:31, 5:238, 6:461, 7:1030, 8:1114, so most records are nearly full rather + than sparse. - **549 of 2,890 adjacent pairs (19%) are exact duplicates of each other.** The most common 8-byte record, appearing 283 times, is `d7d7d780 d7d7d780` -- a 4-byte value stored twice. Others follow the same shape: `00051980 00051980`, `00082580 00082580`. -**Not decoded.** Sparsity plus repeated entries is what a keyframe or index -table looks like, but nothing here establishes that, and the duplicated-4-byte -shape may equally be two adjacent records that happen to share a value. +**Byte 7 is anomalous.** It takes only **14 distinct values** where bytes 0-6 +take 142-204. Its common values are `0x00` (1378), `0xff` (806) and `0x80` +(592) -- the high bytes of signed 16-bit values, which is consistent with +byte 7 being an MSB of something rather than ordinary data. Unexplained. + +**Not decoded.** A signed-16-bit reading was tried and does not obviously +help: the values span -32743..32633, close to the full range, with no +per-position structure (533, 371, 401 and 187 distinct at positions 0-3). Recorded as a characterisation, with its range, so the next attempt starts from the composition rather than re-deriving it.