[game_preservation] Article about proper SNES emulation

[Martin Goldberg]

Henry, please tell me you removed boxed from the shrink wrap
immediately for better preservation. :)


On Mon, Aug 15, 2011 at 12:45 PM, Henry Lowood <lowood at stanford.edu> wrote:

> Istvan,

>

> The Cabrinety Collection at Stanford is a bit unusual, in that most of the

> copies in our collection were acquired in shrink-wrap.

>

> Henry

>

> On 8/15/2011 8:53 AM, István Fábián wrote:

>

> Yes, we are going to address the Japanese systems soon and Joseph leads

> those efforts.

>

> The minimum number for verifying authenticity for most titles is luckily 1 -

> as long as it was professionally duplicated.

>

> For anything else made with non-commercial solutions (i.e. copied on the

> same computer platform etc.) ideally, 3 - but naturally it's never 100%

> certainty for those. It could be just a popular "version" of such disk that

> got widespread due to rampant piracy...

> Unfortunately, it seems that most of the Japanese titles fall into the

> non-commercial duplication category (with the notable exception of a few

> Western titles such as Wings of Fury on the x68000), so it will require

> quite some effort to find copies that we'd have a high enough confidence in

> for being authentic.

>

> The good news is that the majority of the titles for popular platforms

> outside Japan were all duplicated and that includes pretty much all 8 and 16

> bit formats.

> For duplicated disks, it is possible to find inconsistencies in the

> recording that are not present as long as the disk is not modified (or not

> written with a home grade equipment, i.e. copy program), that's why it is

> possible to have an authentic image from a single copy only.

> Actually, many copy-protection methods look for various signs of

> non-commercial duplication in similar ways, but obviously working with

> higher level data than our tools do.

>

> We'd have to see how well that works for e.g. C64 though, but it is

> certainly possible to tell about the first 18 tracks of a C64 disk already

> if it was written on a 1541 drive or a Trace machine, thanks to a mistake in

> the official Trace scripts supplied for that platform.

> This can only be verified with flux transition level dumping, e.g. a device

> like KryoFlux that is capable of measuring individual flux transitions.

> For tracks above 18 we can still look for recording inconsistencies, like we

> do with platforms using generic MFM controllers (PC, ST, Spectrum, CPC

> etc) and the same is possible for FM controllers used for Atari 8-bit, as

> they use the same principle for recording, just encoding itself is

> different.

>

> Again, verifying authenticity from a single copy is only a possibility with

> sophisticated analyser technology and low level dumps from disks.

>

>

> ----- 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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> --

> Henry Lowood

> Curator, History of Science & Technology Collections;

>    Film & Media Collections

> HRG, Green Library, 557 Escondido Mall

> 650-723-4602; lowood at stanford.edu

> http://www.stanford.edu/~lowood

>

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>




-- 
Marty