Re: [ARSCLIST] CDR media longevity

[Chris Lacinak <Chris.Lacinak@xxxxxxxxxxx>]

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
chris@xxxxxxxxxxx


-----Original Message-----
From: Jos Van Dyck [mailto:jos.van.dyck@xxxxx]
Sent: Tuesday, January 20, 2004 5:03 PM
To: ARSCLIST@xxxxxxxxxxxx
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