Mame ROM versions. Why ?

[Happy_Dude]

Why are there different versions of ROMs ?

You'd think that once all the EPROMS on the arcade board where dumped and

named that you wouldn't need to do it again.

I mean the data isn't going to change significantly, or AT ALL, in between mame releases.

So WTF?????

[Nukey Shay]

IIRC, it's because everything is not "fully" supported in Mame. So the sets contain patches to the rom dumps and/or Mame's driver for the game is altered to work around those areas. And some games might be incomplete, so they borrow code from another game that is similar in hardware (so once a full romset can be dumped, the roms would be subject to change). Others need to be decrypted...so again you'd be emulating a patchwork.

[DanBoris]

IIRC, it's because everything is not "fully" supported in Mame.  So the sets contain patches to the rom dumps and/or Mame's driver for the game is altered to work around those areas.  And some games might be incomplete, so they borrow code from another game that is similar in hardware (so once a full romset can be dumped, the roms would be subject to change).  Others need to be decrypted...so again you'd be emulating a patchwork.

 

Actually, ROM dumps used in MAME are never altered to make them work with the emulator, this would be against MAME's preservation goals.

 

There are a couple reasons there could be multiple versions of ROMS. First, the manufacturer of the game may actaully have released multiple versions, maybe to fix bugs or tweak the gameplay a little. For example there are 3 versions of the ROMS for the Exidy game Mousetrap.

 

Second, when ROMS are dumped it's often impossible to know if the data from the dump is actually correct. Most roms don't contain internal checksums or other forms of validation. It may be discovered that a ROM dump that was thought to be correct actually wasn't so it gets replaced with a new dump and MAME is changed to not recognize the incorrect dump.

 

Third, ROM sets might change because missing ROM dumps might be added to the set after the fact. For example a lot of games have color palette PROMS. The emulation can run without these, but it won't generate accurate colors. When the dumps of the PROMS are found they will get included in the ROM set.

 

Hope this helps answer the original question.

 

Dan

[Nukey Shay]

So how does that explain XOR tables? Isn't that a patch?

[DanBoris]

I've haven't been to active in the MAME development team recently, so I may be mistaken, but according to the FAQ:

 

http://www.mame.net/mamefaq.html

 

the XOR tables/files are used to decrypt encrypted ROMS when they are loaded. They modify the data as it's being loaded, the original ROMS files are never actaully altered.

 

Dan

[BigFairy321]

does anyone know a site where i can get an update to my ROMS from 0.67 to the current one?

 

It should be a file or files that incrementally update the romsets.

[Tempest]

Personally I'd love to see a site where they tell the differences between the different rom revisions. Some are fairly obvious (graphical changes, sound changes, etc.) but others look exactly the same.

 

Tempest

[Ze_ro]

does anyone know a site where i can get an update to my ROMS from 0.67 to the current one?

 

It should be a file or files that incrementally update the romsets.

 

You're not likely to find a site like that... but the newsgroups alt.binaries.emulators.arcade and alt.binaries.emulators.misc get incremental updates posted all the time.

 

0.67 is rather old though, so doing incremental updates might take quite a while.

 

Oh, and another change I've noticed when it comes to MAME rom's was in a fairly recent version where they added a huge amount of new Atari revisions (especially Gauntlet, Hard Drivin', APB, etc)... they realized that for some of the games, there weren't using the most recent version of the roms, so now your copy of APB is now your copy of "APB (Version 6)", while "APB" is actually version 7 or something like that. They try to make sure that the "default" version is always the most recent that was released.

 

--Zero

[bjk7382]

My full romset is a mixture between .76 and .77 and I run them with mame32 .79.

 

I never thought you had to update the roms to work with the newer versions of mame. Maybe that is why I have a few hundred games that don't work. (I am missing the letter "U", but I have all the rest)

[BigFairy321]

well i still dont have any trouble running my 0.67 roms with mame 0.78.

when i triad mame32 but a lot of the games wouldnt work, so back to command mame and emuloader frontend which works fine.

 

I think i will only download the necessary new roms which have been relased since mame 0.67.

 

 

I will probably wait another year befor i do a complete romset update.

I would do it now but im still finishing off my c64 emu and amiga500 emu's