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For longest term storage:

The reflective layer is vulnerable to death by oxidization

Gold cannot oxidize

Start by using a gold reflective layer.

Testing can thus be concentrated on gold coated discs only.

All other CD media have birth defects. Let's not divert thinking and testing
time looking for archival almosts.

Steve Smolian



----- Original Message -----
From: "Chris Lacinak" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, January 20, 2004 5:53 PM
Subject: Re: [ARSCLIST] CDR media longevity


> There are at least a few issues that need to be addressed or thought of
when
> using CD-Rs which dictate a decision about brand and dye choice.
>
> 1. Media integrity. You pay for what you get. The effects of media
integrity
> are both short and long term. If you want a fighting chance don't use
price
> to dictate your decision. High Media integrity lends itself to low error
> rates as well as low media defects, which both directly relate to life
> expectancy. Because error rates are key in life expectancy a quality
burner
> and proper burning environment are also important to keep error rates at a
> minimum. Take special note of the burning environment to help keep error
> rates to a minimum.
>
> 2. Life expectancy. Whether you have chosen to use CD-Rs for preservation
> copies or access copies there are a couple of things you can do to ensure
> preservation of your content. One and/or both of these are a good idea
> regardless of the intended purpose of the CD-R, but they are a must when
the
> intended purpose is to create a preservation copy.
>
>         1.Make multiple CD-R copies using multiple brands. Do your
research
> and make an educated choice of multiple CDRs  based on differing
> manufacturers, dyes, error rates, etc... This is a relatively low cost way
> to intelligently spread         the burden of longevity over multiple
brands
> and not put all of your eggs into one basket. The more copies the better
> your chances.
>
>         2.A plan of integrity checks and migration are always a good idea
as
> well. The frequency would primarily be dictated by the size of your
archive.
> If it's small enough you can check everything fairly frequently. If you're
> dealing with a larger archive statistal quality control sampling should be
> implemented. The sampling plan should speak to the number and frequency of
> quality control samples performed, and the resulting actions based on the
> findings.
>
>
> 3. Compatibility. You want to use a CD-R which is compatible with the most
> burners and players. Your chance of finding a player 20 years from now
> (assuming your CD-R is still around) that will be compatible with the
media
> and play it back properly is obviously better with a more compatible CD-R.
>
>         For example, Taiyo Yuden invented CD-R media technology and
> therefore almost all burners and players created are spec'd using Taiyo
> Yuden media. This would logically lead you to believe that greater
> compatibility may be achieved with Taiyo Yuden media. This may be the
basis
> on which you choose one brand of CD-R, while also choosing to use Mitsui
> gold media with Pthalocyanine dye for the longer projected life expectancy
> and so on. 74 min. vs. 80 min. CD-Rs are also a consideration when looking
> at compatibility.
>
> Having said all of this, there are not too many players in the game
anymore.
> Many brands come from the same manufacturer. I can tell you that I have
had
> good experiences with both Mitsui gold CD-Rs and Taiyo Yuden CD-Rs, with
> regard to error rates. Again, it must be noted, when looking at error
rates,
> the significance of the internal and external environments of both the
> "burning" and testing mechanisms. Long term, storage environment plays a
> significant role in increased error rates and should also be given major
> consideration. Storage conditions may help to inform the frequency of
> quality checks.
>
> With regard to other digital storage mediums, all of the ones you have
> listed could arguably serve as reasonable solutions. There are pros and
cons
> to any choice and any number of variables could lead you to any number of
> solutions. The most significant factor is that your quality assurance and
> migration schemes appropriately match the chosen media and associated
> technology. Storage conditions, rate of technology obsolesence, physical
and
> chemical makeup of the media, error correction mechanisms, etc. all help
to
> inform these plans.
>
> The short answer is that there is no simple yes or no answer. The decision
> of the right media and methodologies for you revolve around your goals,
> needs and limitations.
>
> Please note that brand names mentioned are for the sake of example only. I
> have no affiliation with any media company and am not promoting anything
but
> logical thinking and quality.
>
> Regards,
>
> Chris
>
>
> Chris Lacinak
> Director of Production & Operations
> VidiPax, Inc.
> 450 West 31 St.
> 4th Floor
> New York, New York
> Tel. 212-563-1999 xt. 130
> [log in to unmask]
>
>
> -----Original Message-----
> From: Jos Van Dyck [mailto:[log in to unmask]]
> Sent: Tuesday, January 20, 2004 5:03 PM
> To: [log in to unmask]
> Subject: [ARSCLIST] CDR media longevity
>
>
> We are transferring archive radio transcription disks and tapes to CDR for
> digital archiving.
>
> Which media would you recommend for real time (1x) recording, e.g. with
Sony
> CDR-W66?
>
> We tried MAM-E Gold Prostudio, but BLER, E22, E32 (measured with StageTech
> EC2) are unacceptable.
>
> For archives, longevity is of paramount importance.
> However, after a few years some CDRs are showing increasing error rates,
and
> some tracks become unreadable. (e.g. BASF by Ricoh, BASF by Kodak,
Verbatim
> by TDK).
>
> Is systematic error checking of the whole archive needed? At what
intervals?
>
> What other digital storage media is more reliable than CDR (computer
tapes,
> hard disks)? What types of streamer tapes (AIT, DLT, SDLT, LTO)?
>
> Jos
>