Sorry Michael, I sent my reply before reading this very accurate and informative article of yours. Cheers, John Caling Canberra -----Original Message----- From: aus-nsw-hunter-valley-bounces@rootsweb.com [mailto:aus-nsw-hunter-valley-bounces@rootsweb.com] On Behalf Of michael@allbrook.com Sent: Tuesday, 2 January 2007 6:37 AM To: aus-nsw-hunter-valley@rootsweb.com Subject: Re: [HV] NSW BDM ACCESS EXTENDED FOR TRANSCRIPTION AGENTS I read an article about CDs which I found alarming so I typed it out and this is it: COPY OF AN ARTICLE FROM COMPUTER BUYER MAGAZINE - FEBRUARY 2007 ISSUE What's best for backups? I was disturbed to read in the answer to a letter in Computer Buyer the following "CDs & DVDs don't last forever and some cheap discs can be unreadable after a year or two". I use CDs to store master copies of my photographs and videos. What is the general view in the industry about the use of CDs and DVDs for long term storage of digital data? Are any statistics available on the lifespan of discs? I note that you recommend an external hard disc for backup purposes. I am very wary of this as it can put all your eggs in one basket. Using two external discs would solve the problem but it does seem something of an overkill ! >From Norman via email Reply :- Both recordable CDs and DVDs contain an organic light-sensitive dye sandwiched between the plastic layers of the disc. When the transparent dye is hit by a DVD writer's laser beam the dye becomes opaque in that particular spot. Since it is organic, the dye is subject to chemical breakdown over time and this can be accelerated by exposure to light, high temperatures and humidity. (It is worth noting that this process is different to the bacteria-fuelled 'CD rot' that affects the aluminium layer in factory-pressed audio CDs). Blank discs from different manufacturers use different types of dye and some are more prone to degradation than others. Some cheap discs can be unreadable within a year or two of being created while others can last for years. If you plan to use CDs or DVDs for long-term backups, choose high quality brands and store them appropriately - you can get some tips from www.tinyurl.com/2odky. If you are serious about your back ups use MAM Gold Archive Grade DVDs - they are reckoned to be good for 300 years! So that's a contribution from Blighty. My family tell me it is rubbish but its not their hard work that I am storing, its mine and I want a bit of longevity for my efforts Michael Surrey where it is wet and windy -----Original Message----- From: aus-nsw-hunter-valley-bounces@rootsweb.com [mailto:aus-nsw-hunter-valley-bounces@rootsweb.com] On Behalf Of Kathryn M Rogers Sent: 01 January 2007 19:10 To: aus-nsw-hunter-valley@rootsweb.com Subject: Re: [HV] NSW BDM ACCESS EXTENDED FOR TRANSCRIPTION AGENTS < SNIP >

You have added to my knowledge and I thank you. Until a few days ago I had assumed that CDs lasted forever. I am now concerned and I will seek a solution. Paper copies maybe? Michael Surrey -----Original Message----- From: aus-nsw-hunter-valley-bounces@rootsweb.com [mailto:aus-nsw-hunter-valley-bounces@rootsweb.com] On Behalf Of John Caling Sent: 01 January 2007 20:40 To: aus-nsw-hunter-valley@rootsweb.com Subject: Re: [HV] NSW BDM ACCESS EXTENDED FOR TRANSCRIPTION AGENTS Sorry Michael, I sent my reply before reading this very accurate and informative article of yours. Cheers, John Caling Canberra -----Original Message----- From: aus-nsw-hunter-valley-bounces@rootsweb.com [mailto:aus-nsw-hunter-valley-bounces@rootsweb.com] On Behalf Of michael@allbrook.com Sent: Tuesday, 2 January 2007 6:37 AM To: aus-nsw-hunter-valley@rootsweb.com Subject: Re: [HV] NSW BDM ACCESS EXTENDED FOR TRANSCRIPTION AGENTS I read an article about CDs which I found alarming so I typed it out and this is it: COPY OF AN ARTICLE FROM COMPUTER BUYER MAGAZINE - FEBRUARY 2007 ISSUE What's best for backups? I was disturbed to read in the answer to a letter in Computer Buyer the following "CDs & DVDs don't last forever and some cheap discs can be unreadable after a year or two". I use CDs to store master copies of my photographs and videos. What is the general view in the industry about the use of CDs and DVDs for long term storage of digital data? Are any statistics available on the lifespan of discs? I note that you recommend an external hard disc for backup purposes. I am very wary of this as it can put all your eggs in one basket. Using two external discs would solve the problem but it does seem something of an overkill ! >From Norman via email Reply :- Both recordable CDs and DVDs contain an organic light-sensitive dye sandwiched between the plastic layers of the disc. When the transparent dye is hit by a DVD writer's laser beam the dye becomes opaque in that particular spot. Since it is organic, the dye is subject to chemical breakdown over time and this can be accelerated by exposure to light, high temperatures and humidity. (It is worth noting that this process is different to the bacteria-fuelled 'CD rot' that affects the aluminium layer in factory-pressed audio CDs). Blank discs from different manufacturers use different types of dye and some are more prone to degradation than others. Some cheap discs can be unreadable within a year or two of being created while others can last for years. If you plan to use CDs or DVDs for long-term backups, choose high quality brands and store them appropriately - you can get some tips from www.tinyurl.com/2odky. If you are serious about your back ups use MAM Gold Archive Grade DVDs - they are reckoned to be good for 300 years! So that's a contribution from Blighty. My family tell me it is rubbish but its not their hard work that I am storing, its mine and I want a bit of longevity for my efforts Michael Surrey where it is wet and windy -----Original Message----- From: aus-nsw-hunter-valley-bounces@rootsweb.com [mailto:aus-nsw-hunter-valley-bounces@rootsweb.com] On Behalf Of Kathryn M Rogers Sent: 01 January 2007 19:10 To: aus-nsw-hunter-valley@rootsweb.com Subject: Re: [HV] NSW BDM ACCESS EXTENDED FOR TRANSCRIPTION AGENTS < SNIP > ------------------------------- To unsubscribe from the list, please send an email to AUS-NSW-HUNTER-VALLEY-request@rootsweb.com with the word 'unsubscribe' without the quotes in the subject and the body of the message -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.16.1/611 - Release Date: 31/12/2006 12:47 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.16.1/611 - Release Date: 31/12/2006 12:47