[rollei_list] Re: Rangefinder article
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Fri, 15 Jun 2007 16:41:47 -0700
----- Original Message -----
From: "Peter K." <peterk727@xxxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Friday, June 15, 2007 2:41 PM
Subject: [rollei_list] Re: Rangefinder article
Hi Richard,
Thank you. The RW disks actually require the laser to
erase/blank them
before they are written. They usually use a material
different than
dye so that they can control the phase change. The material
is
basically one where a higher power laser and subsequent
cooling
changes the state of the material used. To erase the
pits/disk in a
disk, or blank it, there is a process known as annealing
accomplished
by heating the material to a lower temperature.
Problem with RW is that although the claim is that they will
last a
long time, they do not meet the higher standards of write
once
CD/DVDs. While you might use them for storing images for a
few months,
DVD-R/+Rs are less expensive and offer more stable long-term
storage,
it only makes sense to stick with those if you are
archiving.
UC Berkeley has a good article (from 2001) posted that
offers a better
detailed explanation of the RW process at:
http://www.mse.berkeley.edu/classes/matsci102/F01reports/dvdrw.pdf
Peter K
Thanks Peter, I will check out the reference. I use discs
mainly for storing documents. I expect reasonable life,
several years minimum, but not archival life. It sounds like
I should copy the more important stuff to write-once discs.
FWIW, there appears to be an astonishing amount of
technical publications of historican importance on the web.
For instance, I recently downloaded two RCA internal
publications with all their proprietary knowledge about
designing and making vacuum tubes. This is simply not
available elsewhere.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
---
Rollei List
- Post to rollei_list@xxxxxxxxxxxxx
- Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe'
in the subject field OR by logging into www.freelists.org
- Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with
'unsubscribe' in the subject field OR by logging into www.freelists.org
- Online, searchable archives are available at
//www.freelists.org/archives/rollei_list
Other related posts:
