CDs, was DATs, Was Re: arsclist Duplicating casette tapes

["Steven Smolian" <smolians@xxxxxxxxx>]

George, did any of these tests disclose what surface material was used for
the CDs?

Steve Smolian

----- Original Message -----
From: "George Brock-Nannestad" <pattac@xxxxxxxx>
To: <ARSCLIST@xxxxxxxxxxxxxxxx>
Sent: Friday, August 09, 2002 12:49 PM
Subject: Re: DATs, Was Re: arsclist Duplicating casette tapes


> From: Patent Tactics, George Brock-Nannestad
>
> This is in response to various input, partly quoted at the end.
>
> During the Joint Technical Symposium Paris 2000, Bernd Hänsch
> presented counter-intuitive results that concluded that DAT was in
> practice more stable than CD-R. It turned out that DAT had
> improved and changed little, whereas CD-R had developed quite a
> lot and deteriorated. Read all about it in:
>
> "Image and Sound Archiving and Access: the Challenges of the 3rd
> Millenium - Proceedings of the Joint Technical Symposium Paris
> 2000", Eds. Michelle Aubert and Richard Billeaud, CNC, Paris May
> 2000, pp. 94-103 (including discussion).
>
> During the AES 20th International Conference in October, 2001,
> information was presented which give grave warnings about CD-R.
> The paper by Stanislav Psohlavec was only referred to and
> recommended, but it is printed in "Practical Experience with Long-
> Term Archiving of Data on CD-R", in: "The Proceedings of the AES
> 20th International Conference 2001 October 5-7 Budapest, Hungary
> - Archiving, Restoration, and New Methods of Recording", Co-
> chairs Éva Arató-Borsi and Dietrich Schüller, Audio Engineering
> Society 2001, pp. 15-17.
>
> The paper by Drago Kunej on pp. 18-25 of the same publication
> "Instability and Vulnerability of CD-R Carriers to Sunlight" is a most
> practical and simple approach which is frighteningly realistic.
>
> Based on a variety of information, including the papers introduced
> above, my advice to archives has gradually changed into something
> along the following lines: do indeed use CD-R, but do check
> regularly for quality of the content. Even simple BLER count
> statistics will tell you which CD-Rs will break down before you can
> reconstruct the content perfectly with the very good error correction
> that the system possesses. But it requires a routine and it may be
> costly, but you will actively preserve the data.
>
> Then as to storage and use of the CD-Rs: keep them in the dark,
> do not scratch, do not bend, break off any centre clip plastic parts
> you need in order to get the CD-Rs out of the Jewel Case (the
> original grey-black design never gave a problem, because you can
> push the fingers, but the types where it is all polystyrene integral
> with the case are terrible. Archives are always left with systems at
> the mercy of the manufacturers. And these days there is a veritable
> race to put as much on the CD-Rs as quickly as possible (24x is
> old!).
>
> I am about to go back to R-DATs I made in 1995 (they were copied
> to CD-R in 1999), and if I have trouble, I will let you know. But I
> suspect that they will work fine.
>
>
> > James Perrett wrote:
> > >
> > > Language Laboratories and Archives wrote:
> > >
> > > > Do you have any specifics or sources for the anecdotal reports? I
> > > > am interested because we are doing our archiving to DAT--given
> > > > that the shelf-life of CDs, and therefore, presumably, DVDs is
> > > > really an unknown.
> > > >
> > > > Barbara (----- the originator of the thread)
> > >
> > > I notice that
> > > http://www.hp.com/products1/storage/products/automatedbackup/pdfs/au
> > > toloaders/faqs/NIL002AQV.html#faq14 talks about a life of 10 years
> > > for DDS DAT's. I have also seen this quoted on manufacturers DAT
> > > tape specifications.
>
> >
> > Media Sciences tested helical scan 4 mm and 8 mm DAT tapes for several
> > years. We noticed that repeated passes over the tape resulted in
> > debris pileup and dropouts at the beginning and end of each pass.
> > Heads attached to the rotating drum not only contact the tape but
> > locally deform the tape in order to avoid high frequency gap losses.
> > This would not be an issue for write-once archiving but is important
> > if such tapes are rewritten.
> >
> > Jerry
> > Media Sciences, Inc.
>
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