Segment 4 ‐ Region 13 Analysis

Segment 4 is 8556 bytes long. This was identified by Phenakist when diffing the terminal end of the cartridge data. Segment 4 is supposed to be conserved among all cartridges.

Region 13 was delineated from a pointer in Segment 1 as the closest cutoff to the pre-determined Segment 4, being only 4 bytes off.

Why the mismatch? Is it significant?

Table 1. Four byte area between the start of S4 and R13 for each cartridge.

Cartridge Name	S4-R13 Byte Sequence
The Pokey Little Puppy	00 04 F1 00
The Tawny Scrawny Lion	04 F1 00 00
The Saggy Baggy Elephant	04 F1 00 00
Big Shark Little Shark Baby Shark	04 F1 00 00
Big Shark Little Shark go to School	04 F1 00 00
Big Shark Little Shark	18 04 F1 00
Mister Seahorse	0A 04 F1 00
The Very Quiet Cricket	82 08 F1 00
Slowly Slowly Slowly Said the Sloth	82 00 F1 00

Conclusions

• These bytes do not show congruence even between cartridges of the same series (ex: Puppy, Lion, Elephant).
• No series (so far) exhibits congruence within this area
• Due to the re-emergence of the byte-pattern, there must be a reason that 04 F1 00 is a conserved (to be determined)
• This analysis seems to prove that Segment 4 (the final conserved segment prior to empty filler, as intended) should be reclassified as 8552 bytes long starting at the same address as Region 13.