With the decline in CR-R quality, I first of all think you are entering dangeruos terrain. Even the large respected vendors of quality media now sells outsourced produced CD-Rs under their own name. But you need at least to have an error report on each disc produced to maintain initial top quality in terms of low error rate. I am not sure about the Plextor Premium drive, one of the great problems on CD_R technology is the fact that drives do not have to be buildt to standards, which means that your test result is only as good as your drive, and only consistent using the same drive for retesting. A professional testing euipment would be a nescessity to maintain validity. And with the incisistency in quality and lack of empirical knowledge on the life expectency of CD-R, betting all your money on one type of carrier may be hazardous, and doing the same on one medium carrier vendor is hazardous . You will certainly at least have to monitor your collection based on statistical sampling taking into consideration CD-R vendor, batch, drive used to record and recording speed, but the optimal thing and only sure safe thing would be to monitor all the CD-Rs on a regular basis, comparing error reports and recopying according to this schema. Frame burst errors FBE<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> < 6 Block error rate BLER average < 10 Block error rate BLER peak < 50 E 22 (correctable errors) < 0 E 32 (uncorrectable errors) < 0 Table 1 Section 6.6: Maximum End of Life error levels in an archival CD-R This table will be presented in a publication by the Technical Commision of IASA, the International Assosiation of Sound and Audiovisual Archives, called Guidelines on the Production and Preservation of Digital Audio Objects due to be published this spring, and presented at the Joint Technical Symposium 2004 in Toronto ultimo June. Yours, lars gaustad IASA TC Chair *******************************************' lars gaustad preservation advisor media lab national library of norway +47 751 21 154 www.nb.no -----Opprinnelig melding----- Fra: Holly Dzyban [mailto:[log in to unmask]] Sendt: 3. mars 2004 18:24 Til: [log in to unmask] Emne: Re: [ARSCLIST] refresh plan Sorry, guess I wasn't very clear there, was I? Our collection will eventually consist of roughly 15,000 Mitsui Gold CD-Rs, each of which holds one copy of an analog recording. Say 6,000 will be in a semi-closed archive, used only when the mp3 copies do not have high enough sound resolution for our linguistic researcher. 9,000 will be stored in a closed archive, only handled to make another CD copy if one of the 6,000 is lost or damaged. Between the semi-closed and closed archives, we'll have five copies of each recording, each on a separate CD. Is that enough information? Thanks so much for your help. Holly Don Cox <[log in to unmask]> wrote: On 02/03/04, Holly Dzyban wrote: > My organization is currently in the planning/creation phase of a > digital recordings archive. I am trying to write the refresh plan, and > was wondering if anyone had any advice as far as how and how often to > check or replace the 12,000+ CDs in our collection. Are these commercial, moulded CDs, or are they CDs written in a computer? How often will they be handled? Regards -- Don Cox [log in to unmask] Save Indigenous Languages! HoChunk Renaissance P.O Box 4557 Winnebago, NE 68071 (402) 878-4135 [log in to unmask] _____ Do you Yahoo!? Yahoo! Search - Find what you're looking <http://search.yahoo.com/?fr=ad-mailsig-home> for faster.