[Leica] Re: Fugitive DVDs

[lrzeitlin at optonline.net (Lawrence Zeitlin)]

On Dec 11, 2008, at 6:17 PM, Nathan wrote:

> But which DVDs did he use? The no-name $0.75 ones from Walmart? Like
> with everything else, you get what you pay for. I have always been
> using good-quality, branded CDs and DVDs, mostly the "gold" ones from
> Kodak. When we moved this summer, I decided that I had way too many
> discs around and copied them all onto an external HD. Not a single CD
> or DVD had problems, and they were up to 12 years old. They had all
> been burned on PCs which have long since been recycled, but my iMac
> had no problems with them.


Good point, Nathan. I am now in the process of transferring my CD and  
DVD image files to a hard disc. All could be read. But I've had a  
couple of hard discs fail in the past so I'm keeping the old CDs in a  
shoe box just in case.

Writable CDs are inherently more robust than DVDs. The spot written  
by the laser beam is larger and CDs incorporate error correcting  
codes. They are designed to have a life span of 20 to 100 years,  
depending on which manufacturers PR department wrote the  
specifications. My university uses CDs for archival storage. But then  
they burn multiple copies.

You can buy "archival" CDs if you are willing to pay big bucks. But I  
suspect that the inflated price is a marketing ploy designed to boost  
user confidence. Kodak advertised that their gold CDs had a 100 year  
estimated life. But it is not unheard of for some CDs to "rot" in a  
couple of years. DVDs, on the other hand, are optimized for cramming  
as much data as possible into the disc. Video takes a lot of bits.  
The writing density is five times higher than that of a CD and little  
error correction is normally employed. Writable discs use dyes as the  
recording medium. Just like color film, these dyes may deteriorate if  
exposed to bright light or warm temperatures. The moral seems to be  
that CDs are longer lived than DVDs and both will last much longer if  
kept in cool dark places. Don't use CDs as coffee cup coasters, as  
one of my friends did, and expect a long life without errors.

As far as price goes, quality name brand DVDs (Sony, Fuji, Memorex)  
are available in stacks of 100 for less than $20 at most large US  
office supply stores. A $0.75 CD is a premium item.

Larry Z