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Which version of a ROM to work with

Started by tryphon, November 03, 2014, 11:22:04 AM

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tryphon

I'm working on some Genesis games and for the moment, I didn't bother about identifying precisely the original ROM.

Now that I try, I realize that several version of them exist.

For example, I work on Moving Adventure Psy-O-Blade and Rent-A-Hero, and I found those, all in Goodgens 3.0 :

Rent A Hero (J) [!]
Rent A Hero (J) [h1C]
Rent A Hero (J) [h2C]

Psy-O-Blade Moving Adventure (J) [!]
Psy-O-Blade Moving Adventure (J) [h1C]
Psy-O-Blade Moving Adventure (J) [o1]

The size are not the same : Psy-O-Blade Moving Adventure (J) [o1] is 1024 kB long whereas others are 640 Kb. I didn't try to analyze the extradata,but it's not zeros.

Could someone explain what the letters mean and which version is the more suitable as a base for a hack ?

STARWIN

quick google for letter definitions: http://en.wikipedia.org/wiki/GoodTools

it seems that you only have one real choice for each

mziab

#2
When looking for clean roms, you should basically steer clear of most square bracket codes, with the sole exception of [!]:

[hXX] are hacked roms, in practice just a hacked header is enough to warrant this label.
[oX] are overdumps, which will work but as the name suggests contain redundant data.
[!] are verified dumps, which is a Good Thing™.

On a related note, the policy of including even known bad dumps in GoodTools is the exact reason why many people have switched to NoIntro sets, which contain only proper dumps.


obscurumlux01

Please be sure to use the ! versions of the ROMs.  There should be some utilities that verify those ROMs for you.  I'm currently aware only of one command-line utility for non-SNES roms (uCON).

snarfblam

ROM Hasher can check ROMs for most systems against the No-Intro database.

tryphon

Marvellous. Downloaded, thanks :)

While I'm at it, must I compute all check values for an ISO (PS2 game) if I want to submit a translation, and if so, can I use ROM Hasher ?