> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:[log in to unmask]] On Behalf Of George Brock-Nannestad
> Sent: Tuesday, August 09, 2005 9:23 AM
> To: [log in to unmask]
> Subject: Re: [ARSCLIST] "Archival" DVD-R?
> From: Patent Tactics, George Brock-Nannestad
> Dear All (and this means the archiving community in its broadest sense),
> we are constantly bombarded with discussions of stability of Recordable
> Optical Media, all very responsible and well-documented - I do not mind to
> > Joav Shdema:
> > I have the following very current PDFs that deal with the subjects we
> > discuss here:
> > 1) Stability Comparison of Recordable Optical Media
> > 2) Discs—A Study of Error Rates in Harsh Conditions
> > 3) Care and Handling of CDs and DVDs —A Guide for Librarians and
> > Archivists
> > 4) DVD-ROM Drive Compatibility Test for DVD-R(General), DVD-RW, DVD+R,
> > DVD+RW and DVD-RAM Discs
> ----- however, there are TWO trees that we need to bark up:
> - the tree that everybody is already dealing with
> - a stable CD or DVD is worthless if there is no equipment - drive - that
> will read it. It does not matter if incompatibility between drive and
> only develops over time - the result is worthless in any case.
> ----- I have not seen any work reported on the long-term performance of
> drives. To my knowledge there has been no accelerated aging of drives, no
> continuous exercizing of drives until they break down (they do that to
> chairs, you know!)
> ----- there are several directions that product development takes. Early
> generations are often very conservatively built, although virtually no
> equipment is built that needs maintenance, such as lubrication. Functional
> units are replaced instead. Such conservatively built equipment is
> in manufacture and in materials. For this reason, product development
> to replace ceramics, glass, and metal with plastic, and furthermore, more
> more elements are made as complete castings, reducing assembly labor.
> ----- in a CD player, the original HeNe laser was quickly replaced by
> diodes. Glass lenses were replaced by plastic. I have not studied this in
> detail, but there has been 25 years of development.
> ----- over the years, I must have disassembled about ten 3˝" floppy drives
> (from the 720kb of the 1980s to 1.44 Mb of the 2000s), and the experience
> not been happy. Just as an example: where the carriage for positioning of
> reading head originally had brass (or bronze) bushes sliding on a polished
> steel rod, that was replaced by plastic. Plastic may distort with time.
> ----- I have also disassembled a number of hard drives. Inside, everything
> seems to be professional quality, no plastic, except where relevant for
> weight and insulation, and precision ball bearings
> ----- in terms of DVD or CD drives: will the surface of the lens corrode
> time and temperature? Will the material cloud? Will semi-reflecting
> corrode? Will the carriage warp? Is there anything like "purple plague"
> regarding integrated circuit termination anymore? Mothballing may not be
> ----- in conclusion I would like anybody who feels the urge to undertake
> "stability tests" on optical disc media, to take the appropriate drives to
> their local engineering department and to discuss the actual mechanical
> electrical design. You will receive explanations for why a particular
> material and configuration choice was made, and you will have a sparring
> partner who will be able to predict performance under stress.
> ----- I fear that you will discover that you can only trust optical media
> while the current generation of media and equipment is industrially
> supported. Say five years, to be conservative.
> ----- I shall not respect future analyses of longevity, unless it is a
> analysis, not a medium analysis. I know that it is much more expensive
> leaving your discs out on your desk or in a car and monitoring the
> progressive problems. But without a drive, all we preserve are mirrors
> optical gratings.
> Kind regards,
One key problem is that there are no standards for drives, only for media
quality. What determines whether a drive is acceptable or not, other than
complete loss of functionality?
Media Sciences, Inc.