[game_preservation] Article about proper SNES emulation
István Fábián
if at caps-project.org
Wed Aug 17 12:29:29 EDT 2011
Hi Henry,
It's better to double-check for sure - please see my email, about details
what can be done to recover bad data as part of a data recovery service.
Whether your forensic lab does that or not, really depends... I'd rather not
risk that, especially when safer technology is available.
Regarding my email, here is a reference for tapes:
http://www.fxgroup.net/tape+baking
Kind regards,
István
----- Original Message -----
From: "Henry E Lowood" <lowood at stanford.edu>
To: "István Fábián" <if at caps-project.org>
Cc: "IGDA Game Preservation SIG" <game_preservation at igda.org>; "Frank
Cifaldi" <fcifaldi at gmail.com>
Sent: Wednesday, August 17, 2011 5:13 PM
Subject: Re: [game_preservation] Article about proper SNES emulation
István,
>From everything I have been told about the forensic software and training,
it is precisely a key point that any alteration of the original medium is
forbidden. In fact, one feature of the workstation is a write blocker that
supposedly insures that the source medium is unaltered. If you consider the
legal context for forensic tools, this only makes sense.
As for the forensic lab, that is certainly something we can inquire about.
They might have a different philosophy from the investigative use of
forensic tools -- I just don't know.
Henry
----- Original Message -----
From: "István Fábián" <if at caps-project.org>
To: lowood at stanford.edu, "IGDA Game Preservation SIG"
<game_preservation at igda.org>, "Frank Cifaldi" <fcifaldi at gmail.com>
Cc: "IGDA Game Preservation SIG" <game_preservation at igda.org>
Sent: Wednesday, August 17, 2011 2:02:41 AM
Subject: Re: [game_preservation] Article about proper SNES emulation
I agree this would be a huge step forward in preserving disk based media and
we'd be happy to give our expertise, regardless of whether the media
contains games, productivity software or other content.
I can only speak for SPS, but I am sure that Stanford as well would welcome
any help we could get to make this happen.
I also agree, that finding some of the software in an unmodified form would
be extremely unlikely otherwise.
I have concerns about what a forensic lab would do with copy protected
disks: given their field of work, they may assume the unreadable data is bad
and might try everything to recover that "bad" data which might include
physical alterations of the disk... certainly not something we want to
happen with potentially the last known existing and unmodified copies of
some software.
I am going to send the details to Henry.
István
----- Original Message -----
From: Henry Lowood
To: Frank Cifaldi
Cc: IGDA Game Preservation SIG
Sent: Wednesday, August 17, 2011 4:25 AM
Subject: Re: [game_preservation] Article about proper SNES emulation
Thanks, Frank. I have enormous respect for SPS (still thought of as CAPS)
and the work they have done. I'm hoping we can do this.
Henry
On 8/16/2011 10:45 AM, Frank Cifaldi wrote:
I'm not exaggerating when I say that the proper bit-for-bit preservation of
Cabrinety's untouched games might be one of the most important immediate
initiatives this group should focus on, I am willing to bet that many pieces
in that collection represent the only "untouched" copies of those games. I'm
really glad to hear you guys are communicating, Henry let me know if you
need any volunteer manual labor or anything to make this happen.
On Mon, Aug 15, 2011 at 1:42 PM, István Fábián < if at caps-project.org >
wrote:
The short answer is yes, I am about to send a longer email to your address.
István
----- Original Message -----
From: Henry Lowood
To: IGDA Game Preservation SIG
Cc: István Fábián
Sent: Monday, August 15, 2011 6:45 PM
Subject: Re: [game_preservation] Article about proper SNES emulation
Istvan,
The Cabrinety Collection at Stanford is a bit unusual, in that most of the
copies in our collection were acquired in shrink-wrap. We are already
considering a proposal to make the computer game part of the collection
available to a forensic lab in the US for imaging. Is it possible that
access to our collection would be helpful in the case of ROM cartridges
(home console games)? If so, we should consider working together; I believe
that our only condition would be some way to cover expenses of preparing and
registering the items, maybe shipping, and then deposit of the images in our
digital repository (non-exclusive license). If there is interest, I would
then have to speak with colleagues here, so for now, I'm just asking if
there is interest in pursuing this.
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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game_preservation mailing list
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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
_______________________________________________
game_preservation mailing list
game_preservation at igda.org
http://six.pairlist.net/mailman/listinfo/game_preservation
--
Henry Lowood
Curator for History of Science & Technology Collections;
Film & Media Collections
HSSG, Green Library
557 Escondido Mall, Stanford University Libraries
Stanford CA 94305-6004 USA
http://www.stanford.edu/~lowood
lowood at stanford.edu; 650-723-4602
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