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pc-capcombeatemupbundle-doc

Measurements of Capcom Beat 'Em Up Bundle (Capcom, 2018) as Steam installs it: 268 files, 809,632,531 bytes, read-only, no medium.

Seven CPS1/CPS1.5/CPS2 arcade games from 1989–1997, sold as one PC product. Internal project ibis, module BSAC, engine MT Framework.

This repository publishes measurements and the code that reproduces them. It contains no ROM bytes, no textures and no extracted game data — hashes yes, bytes no.

the short sheet

object CBEUB Steam install, app 885150, depot 885151, build 11421272
files / bytes 268 / 809,632,531 — matches Steam's own SizeOnDisk exactly
executable CBEUB.exe, 6,305,176 bytes, PE32+, linked 2022-04-18, version 1.0.0.2
readable fraction of the executable 28.59 %.text is 4,502,528 bytes at entropy 8.0000 behind a Steam wrapper
containers derived here ARC\0 v7, IBIS v4, TEX\0, GMD\0
archives 252, residue 0 on 252 of 252; 426 members, 426 of 426 inflate to declared length
resource type hashes 13, 13 of 13 resolved as (~crc32(class name)) & 0x7FFFFFFF
arcade ROMs 14 containers, 214,565,760 bytes, four regions each, residue 0 on 14 of 14
distinct arcade programs 11, not 14 — three pairs are one program with a patched constant
thesis figure 80.09 % — the gallery's share of the install
absolute paths 1, over 28.59 % coverage
personal names found by scanner 0 · named in the product: more than a hundred
cross-collection hash hits 0 of 687, over 106 repositories
the question not determinable from the shipped files12

the three findings

1. Eighty per cent of this product is a picture gallery. 648,440,086 bytes of scanned arcade flyers, character sheets and painted key art, against 72,932,448 bytes — 9.01 % — for the seven games it exists to sell. Decoding the .tex format was the price of knowing that, and this collection had never opened one.

2. Every secret the original hardware kept has been unwrapped before shipping. The CPS2 program cipher, the Kabuki sound-CPU cipher and the CPS graphics interleave are the three things about these boards that cannot be derived from the ROMs. All three have been applied offline: the CPS2 sets carry ciphertext and plaintext side by side, the Q-Sound sets carry the encrypted Z80 at 0x00000 and its plaintext at 0x28000, and the graphics ship as flat 16×16 4bpp tiles.

3. Which means the most discriminating test of authorship is not blocked — it is designed out of the product. The running program never needs a key or a per-game table, so there is none to find, and there would be none even if the packed .text were readable. That is the substance of 12-question.md, and the answer there is not determinable from the shipped files, published with everything that was tried and a list of what would close it.

chapters

00 — predictions written before anything was opened; 12 inherited clauses, 59 open
01 — the object what it is, the content definition, and the 80.09 %
02 — datasheet every figure with the command that reproduces it
03 — the executable PE, the wrapper, the version resource, the imports, the set-name table
04 — the .arc container format, census, and thirteen type hashes resolved
05 — the IBIS container fourteen ROMs, and a header the pre-briefing got wrong
06 — the four regions 68000, graphics, Z80, samples — identified from the bytes
07 — ciphertext and plaintext the doubled CPS2 region, and the Kabuki copy
08 — the byte that changes eleven programs in fourteen containers
09 — the .tex format derived, and the eighty per cent finally looked at
10 — the credit roll a hundred names and six companies, all in pixels
11 — eight languages the GMD table, and the missing language index 6
12 — whose emulator the chapter this session exists for
13 — provenance the build id, found one directory up
14 — leftovers 989 MB of it, on an object with no medium
15 — corrections twelve in the pre-briefing, four of mine
16 — against the collection four Capcom containers in twenty-two years
17 — scoring 10.5/12 and 52.0/59, and a calibration that flipped sign
18 — personal data the scanner's zero, and what it was a zero about

tools

Twelve new readers were written for this object, each with --validate before anything else and a negative control that fires:

mtarc.py · ibis.py · mttex.py · ddswrap.py · gmd.py · mttype.py · pe.py · m68k.py · z80head.py · romcensus.py · pairdiff.py · tilepeek.py

notes/ carries sha1-all.txt (268 files), sha1-arc-members.txt (426 members) and sha1-rom-regions.txt (56 regions) — the first hash lists this object has ever had.

the object was not modified

Nothing in this repository writes to I:\SteamLibrary. The game was never launched by this session, no process was attached, no memory was dumped and the Steam wrapper was not unpacked. Where a question required any of those, the answer recorded is that the question is not answerable from the shipped files.

About

Measurements of Capcom Beat 'Em Up Bundle (PC, Steam, 2018): 268 files, 809,632,531 bytes. Derives the ARC/IBIS/TEX/GMD containers, resolves 13 of 13 MT Framework type hashes, identifies all four regions of all 14 arcade ROMs, and answers 'whose emulator' with a measured non-answer.

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