Author Topic: Q about ROMs made using the Retrode  (Read 3450 times)

Offline DigitalArchivist

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Q about ROMs made using the Retrode
« on: 21/Feb/2012 11:38:39 PM »
Hello. I am a student working on a project at an archives related to digital reproduction and emulation of video games. I am currently researching hardware necessary to digitally clone video games that are contained in the archives, and I came upon the Retrode because we have a large number of Sega Genesis games. First off, I'd like to say that I am incredibly excited that people are doing this kind of preservation work.

I poked around on the front page for a while and read the FAQs, but I couldn't find an answer to my question. While we'll probably be satisfied to make any kind of digital backup of the games, the ideal archival standard is to make a bitstream-level copy with a checksum to ensure that the ROM is, for all intents and purposes, identical to the game on the cartridge. I have worked with CDs and some legacy media (3.5" and 5.25" floppies, mostly) creating disk images using the disk dump (dd) command on Linux to achieve this. I was wondering whether the Retrode works using a similar function, and if so, if it generates similar checksum values/error checks the files to ensure that the copy is a clone.

Apologies if this information is somewhere, I couldn't find it.

Thanks a lot!

Offline Matthias_H

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Re: Q about ROMs made using the Retrode
« Reply #1 on: 22/Feb/2012 12:24:31 AM »

You would have to identify the checksum in the ROM header, and check it against the data. The Retrode does not perform any checksum test of its own, but many emulators do that upon loading. Please note that some carts actually contain faulty checksums, in which case there simply is no proper way to verify it, other than by comparing it to known true dumps.

For mapper-less cartridges, the dumps obtained are identical copies of the data provided the ROM chip. Of course, in very rare cases a cartridge may map special hardware into the ROM address space, in which case you will likely end up with bogus data for that particular memory range. I know of no occurrence of that actually happening.


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Offline Muzer

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Re: Q about ROMs made using the Retrode
« Reply #2 on: 22/Feb/2012 08:57:05 PM »
Yeah - it's worth noting that the Retrode exposes the checksum in the header in the filename for the game itself - but, as he said, they're sometimes wrong. It is useful, though, especially to just check it against the size (which is sometimes detected incorrectly, especially if you hotswap the games)