[rollei_list] Re: why I'm not digital -( just for interest)
- From: "Peter K." <peterk727@xxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Sat, 15 Apr 2006 18:17:50 -0700
With al due respect Jim, the deterioration is more for CD-Rs than the CDs
you buy at a music store. The reason being the latter are coated and the
material burned is less affacted by light. Stored properly they will last
many decades. The CD-Rs you burn on your computer can deteriorate in a very
short time (less than a few months) if not properly stored, or properly
stored 20+ years. But the material that is used to make them is not as
important as the burn itself. Many people burn them at high speeds, this is
fine but a slower speed will yield a better (albeit slower) burn and they
will last much longer.
If you don not believe this, burn one at 40X and another at 1x, leave them
in the sun for a few days, then see what happens. I would be the slower burn
one will still be readable.
Peter K
On 4/15/06, Jim Brick <jim@xxxxxxxxx> wrote:
>
> At 09:13 PM 4/14/2006 -0700, Don Williams wrote:
>
> >and if you get a properly made DDD CD it's going to be predictably
> >good, and if it's not good, it won't get any worse with time.
>
>
> CD's & DVD's have an absolute finite life. The run of the mill brands
> will last from eight to fifteen years, depending upon how they are
> handled. Store them at 25% humidity, in the dark, in an archival
> sleeve and they might make twenty years.
>
> The new archival CD's & DVD's that are supposed to last 100 years,
> might, if they are immediately, upon manufacture, placed in super
> archival storage, never to be opened during that 100 years. By this
> time, CD/DVD technology will have been forgotten.
>
> I have a dozen or so mag tapes from my work on mainframes during the
> 60's and 70's. They are totally void of data now, simply from bit
> rot. CD's and DVD's that you burn on your computer are created via a
> chemical reaction within the CD/DVD layers. This chemical reaction
> (brought on via the laser pulse) will continue on for the life of the
> CD/DVD. How much it is used (reading via laser accelerates the
> reaction), left out in heat and humidity, will determine its
> longevity. CD/DVD bit rot is real. It's just a chemical reaction
> rather than a magnetic reaction.
>
> Commercial CD's are pressed - just like vinyl - and have a longer
> life. But it is just a little longer than personally burned media as
> it to has the chemical layers that are changed by pressure for laser
> refractive reading.
>
> Folks who think they are archiving their photos on CD's & DVD's are
> in for a rude awakening, if they do not migrate ALL of their
> photographs to new media every five years.
>
> If bits are dropped in photo files, the checksum will be incorrect
> and your program, eg Photoshop, will not read the file. A recovery
> program will. Then you can spend countless hours in Photoshop
> correcting (replacing) all of the damaged data. No one will do this
> for hundreds/thousands of photographs.
>
> Also, your grand kids, and their grand kids, cannot sit down with a
> box of photographs and see their heritage. You will have left it to
> them on media that has either gone bad, or is technologically passe.
>
> I have a box of photographs, of my family, from the late 1800's. the
> negs are still good and the prints are also still good. This probably
> would not have lasted if it were on digital media.
>
> At some point in the near future, some sort of very archival media
> will be produced. But it has to be something that will remain
> readable for a hundred years or so. Technology cannot pass it up, and
> the media cannot be effected by bit rot. It will happen as the
> digital photography revolution will demand that it happen.
>
> Me... I use film. I do have a Sony T7 in my purse, oops, excuse me,
> my "man bag," for recording things of immediate interest. Not family
> stuff that might become vaporized in a HD or CD crash.
>
> The way I archive everything (on my computer) that is of value to me,
> is: I have two external, very large, hard drives. USB 2.0. I save
> what I want saved to one drive, then I plug in the other drive and
> copy the entire first drive to the second drive. I then unplug one of
> the drives. I always have two duplicate hard drives of my good stuff.
> Only one is ever plugged in and running, other than when being
> copied. Should one drive ever fail, I will get a new drive, copy the
> good drive's data to it, and I again have fail free storage. The
> chance of both drives failing at exactly the moment time is in the
> billions, or trillions to one. And it doesn't matter if technology
> changes. As it does, just upgrade with it.
>
> :-)
>
> Jim
>
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--
Peter K
Ó¿Õ¬
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