About ROM Size

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root
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About ROM Size

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Rif: 537 About ROM Size \ Yakushi~Kabuto on 29th March 2006, 18:45 wrote:

Here is a log of a discussion I got with the #1 snes ROM specialist: Nach
[20:38] <X-or> do you remember that talk about rom sizes?
[20:38] <Nach> yes
[20:38] <X-or> have you got actual examples of a game which has several pcb sizes
[20:38] <X-or> (hope it was understandable)
[20:40] <Nach> well, we found a ton of overdumps
[20:41] <Nach> some were overdumped because the hardware didn't understand how a PCB could be smaller
[20:41] <Nach> IIRC though, one of those basketball games we found both ways
[20:42] <Nach> I haven't kept lists of what used to be
[20:42] <Nach> ooh wait a sec, I think I had an example from Overload
[20:44] <Nach> SD The Great Battle
[20:44] <X-or> if I understood correctly a same game can be found in both a 12Mb or 16Mb pcb (for instance)
[20:44] <Nach> yes
[20:44] <Nach> if the game is only actually 12Mb
[20:44] <Nach> or 10Mb...
To sum it up, some games exist in two versions
SD The Great Battle (sfc) exists in both 8Mb and 16Mb chips even tho in both case the actual game data is lesser than 8Mb.

Why do I talk about this? Because it means the 'correct' ROM size is not necessarily the chip size but the 'useful' game data size (size before burning as NGEfreak says). Dumps should always be trimmed to the lowest size possible (Tho it must be a multiple of PCB chip size).

Recently a ROM in the N64 set was extended from 4MB to 16MB (frogger 2 -alpha IIRC). 4MB of game data + 12 MB of 0xff. That 16MB ROM must be considered as an overdump.

I tried not to be too technical so I hope everyone got it. I think that clarification was necessary for everyone.

================================================== =

SNES ROM SIZE DRAFT:

Toshiba:
TC538 : 8 Mbits
TC5316 : 16 Mbits

Macronix:
MX23C16 : 16 Mbits
MX23C32 : 32 Mbits

Sharp:
LH5S4 : 4 Mbits
LH538 : 8 Mbits
LH537 / LHMN7 : 16 Mbits
LH536 : 24 Mbits
LH535 / LHMN5 : 32 Mbits

???
CAT534 : 4 Mbits
CAT538 : 8 Mbits

Mitsubishi:
M5316 : 16 Mbits

Hitachi:
HN62318 : 8 Mbits

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Re: About ROM Size \ SolidSnake on 29th March 2006, 19:56 wrote:

For example! The Nintendo DS Games! :) Thats what i'm always say!

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Re: About ROM Size \ Yakushi~Kabuto on 13th February 2007, 10:19 wrote:

In the snes dat, there are several entries with a size of 1310720 (10Mbits)
Does such size even exist? The only valid chips size I know about for the super famicom are 4,8,16 & 32MB. 10 is not a multiple of 4 so it would need a 2Mbit chip... I have never seen a 2MB rom chip on a snes PCB. So please would you mind posting your evidence?

I checked a few ROM that are trimmed from 8Mb to 6Mb by NSRT
The 2Mb removed by the tool are not filled with 00 or FF, the bytes are pretty random. Removing that 2Mb chunk seems pretty foolish to me :?

I may have missed something, so please enlighten me

LOL! just after saying that, I found a 2MB chip in Galaxy Wars cartridge XD
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