+segments

_posts/2024-04-23-searching-for-the-index.markdown

@@ -18,10 +18,31 @@ Now let us visualise the two larger segments `un2.dat` and `un3.dat`
 as follows: we interpret each byte as a greyscale value in the range
 0...255:
 
+## unknown2
+
 ![](/img/un2.png)
 
 (image created with `./src/mp.py -c vis_bytes --out img/un2.png un2.dat`)
 
+We can distinguish several segments.
+
+## unknown3
+
 ![](/img/un3.png)
 
 (image created with `./src/mp.py -c vis_bytes --out img/un3.png un3.dat`)
+
+We see two segments, each with a quite regular pattern. The regularity
+of the second segment is revealed already by `hexdump`:
+
+```
+0028c530  35 48 dd 1f 89 48 17 01  cd cd 3d 02 00 00 91 df  |5H...H....=.....|
+0028c540  35 48 f2 0d 89 48 18 01  cd cd 3d 02 00 00 c3 e5  |5H...H....=.....|
+0028c550  35 48 25 ec 88 48 19 01  cd cd 3d 02 00 00 21 13  |5H%..H....=...!.|
+0028c560  36 48 ef bf 88 48 1a 01  cd cd 3d 02 00 00 e0 ff  |6H...H....=.....|
+0028c570  35 48 c6 a4 88 48 1b 01  cd cd 3d 02 00 00 2e de  |5H...H....=.....|
+0028c580  35 48 2a a4 88 48 1c 01  cd cd 3d 02 00 00 45 ad  |5H*..H....=...E.|
+0028c590  35 48 51 a8 88 48 1d 01  cd cd 3d 02 00 00 fe b1  |5HQ..H....=.....|
+0028c5a0  35 48 eb 9a 88 48 1e 01  cd cd 3d 02 00 00 ae cc  |5H...H....=.....|
+0028c5b0  35 48 c3 8b 88 48 1f 01  cd cd 3d 02 00 80        |5H...H....=...|
+```