[game_preservation] Article about proper SNES emulation

[István Fábián]

As for checking integrity in most cases the number is again 1, a single copy is enough.

The only exception is, when the format does not hold an integrity information - it may sound like a bad idea nowadays, but this really happened at the time.
In some cases the duplicators themselves added integrity information to those disks (so they could verify the duplicated disks) and it's usually possible to guess what method they used so we can verify those disks even if judging by the format itself (via reverse-engineering) there is no integrity information present.

However very rarely, disks were really being duplicated without any verification at all.
What we do in those cases is to verify the consistency of the encoding of the data recorded, i.e. violations in the encoding itself always point out read errors, peak shifts etc. and compare multiple copies of titles without any encoding defects just in case.
  ----- Original Message ----- 
  From: Devin Monnens 
  To: IGDA Game Preservation SIG 
  Sent: Monday, August 15, 2011 3:14 PM
  Subject: Re: [game_preservation] Article about proper SNES emulation


  Istvan,


  Thank you for clearing that up. To this list, I would also add something else: making a catalogue of what is available for that platform, including version numbers and variations.


  Approximately what percentage of the different platforms have already been archived? I also know there is a group in Japan working on disk-based games lead by Joseph Redon.


     it takes a lot of time of processing the disks afterwards to check the authenticity and integrity of the content.
    Hoping that every disk image made is correct is just wishful thinking considering the age of the media and how common it is to find modified content.


  What is the minimum number of disks to have to verify for authenticity and integrity? Do you need at least two copies to make sure there were no errors? I didn't see any mention of this on the knowledgebase of your site.


    So far we've spent 7 digit amounts to preserve about 3600 titles and to develop the necessary technology - and about 10 years.
    It is however not something that we can really afford to do far longer...


  7 digits in Euros? That would be more than twice the amount in USD! Is Kryoflux helping to solve this problem by distributing the work to collectors and libraries? Have you run into any cases where someone has the game but doesn't have access to a Kryoflux device? If that's the case, it might be possible to purchase one and then mail it from place to place.


  -- 
  Devin Monnens
  www.deserthat.com

  The sleep of Reason produces monsters.



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