KaTeker Backup
media
KaTeker Backup
media
Disclaimer
Safety
of data
Rules of thumb saving reliable data on CD and DVD
Under no circumstances may Dr. Heiner Kuhlmann be held liable for damage to hardware or software, lost data or other damage either direct or indirect caused by using this description.
Think about the fact, that the data saved may be sensitive data and media like CD and DVD can be purloined. Reading the data is simple. That is it is a good idea to the media into a save. Furthermore the media should not be placed nearly the computer. In case of a fire or a theft the computer and the data saved will be lost. I save master backups in a safe at a bank.
Backup data are sensible data. A backup is useless if the data cannot be restored. The reliability depends on the media the handling and storage of the media. The drive saving and reading the media has an effect too.
The author was some years responsible for the backup of the data of a large software product. The backup was save on hard disks, DAT tapes and MO media. There have been a lot of problems with DAT tapes. The drives failed. The tapes failed very often. At the same time no HD crashed nor a MO media or CD-R was not readable. Other tape systems are much more reliable but also much more expensive.
Although there are a lot of successful stories about saving data on tapes.
There is another drawback of tapes: the long access time. The media are cheap, while the drives are expensive.
This is because KaTeker supports no tapes.
KaTeker supports backup onto
hard disk
CDR
CDRW
It is no problem to extend KaTeker to backup onto
network storage
DVD
MO
ZIP
USB hard disks
USB memory sticks
Compact-flash
There are some solutions in the alpha state. Please contact the author.
Backup should be stored on media of different type i.e. on hd and CD. The focus of this part on the second media type. Ordered by reliability these are:
MO
DVD-RAM
CD-R
DVD-R
CD-RW, DVD-RW, DVD+RW
all others
The drawback of MO are the costs. There are cheap DVD recorder available supporting DVD-RAM thus DVD-RAM is my favorite.
The following discussion is focused on CD-R, CD-RW, DVD-R, DVD-RW and DVD-RAM
Copied from http://www.cdrfaq.org
CD-RWs are expected to last about 25 years under ideal conditions (i.e. you write it once and then leave it alone). Repeated rewrites will accelerate this. In general, CD-RW media isn't recommended for long-term backups or archives of valuable data.
The rest of this section applies to CD-R.
The manufacturers claim 75 years (cyanine dye, used in "green" discs), 100 years (phthalocyanine dye, used in "gold" discs), or even 200 years ("advanced" phthalocyanine dye, used in "platinum" discs) once the disc has been written. The shelf life of an unrecorded disc has been estimated at between 5 and 10 years. There is no standard agreed-upon way to test discs for lifetime viability. Accelerated aging tests have been done, but they may not provide a meaningful analogue to real-world aging.
Exposing the disc to excessive heat, humidity, or to direct sunlight will greatly reduce the lifetime. In general, CD-Rs are far less tolerant of environmental conditions than pressed CDs, and should be treated with greater care. The easiest way to make a CD-R unusable is to scratch the top surface. Find a CD-R you don't want anymore, and try to scratch the top (label side) with your fingernail, a ballpoint pen, a paper clip, and anything else you have handy. The results may surprise you.
Keep them in a cool, dark, dry place, and they will probably live longer than you do (emphasis on "probably"). Some newsgroup reports have complained of discs becoming unreadable in as little as three years, but without knowing how the discs were handled and stored such anecdotes are useless. Try to keep a little perspective on the situation: a disc that degrades very little over 100 years is useless if it can't be read in your CD-ROM drive today.
Copied from http://www.americal.com/pg/dvd-r-faq.html
All DVD recordable discs are extremely sensitive to heat, UV light and humidity. You should avoid exposing them to any extremely hot environment such as automobile interiors in the sun, or inside near radiators or heaters, or near an outside window, and so on.
It's best to keep all DVD-R discs stored in a cool, dry place, closed up in a blank plastic DVD movie case. This will ensure that they last the longest.
Avoid any abrasive, scratching or etching treatment of the disc's top or bottom. Remember that they are much more sensitive than DVD Video or Game discs, and that even a small scratch can make them unplayable.
However, a scratched DVD-R can be destroyed in seconds, and one exposed to high temperatures, humidity or strong UV light sources can become unplayable within anything from a few hours to a few days. One study of average DVD-R discs stored at 80 degrees and high humidity showed that many of them became unplayable in only a few hundred hours. Imagine what storage in a sun-heated car interior's "oven" at about 200 degrees would do!
Treat your recorded DVD-Rs with care. Handle them by their edges, gently. Avoid harsh chemicals in marking pens, ink and label adhesives. Avoid touching the top or bottom surfaces. Don't slide them across tables, players or computer cases. Return them to their black DVD cases immediately after playing. Don't stack DVD-Rs one on top of each other and shuffle them like a deck of cards.
Do buy white coated DVD-Rs. The extra top coating can add a bit of extra protection against some chemicals and minor nicks and abrasions. Do buy gold metal reflectors when you want to get the absolute longest storage possible. Gold does not tarnish. Silver alloy metal reflector discs can last for many years also, especially with the white top.
With proper handling and protection during storage, a DVD-R disc can last for longer than you will probably want to re-play them. One company claims that its DVD-R discs can last up to 100-years or more. Store your own DVD recorded discs carefully in a cool, dark, dry place and they should last for many years.
DVD-RAM can be rewritten more than 100,000 times, and the discs are expected to last at least 30 years. It combines improved technology of CD-RW with some of MO and a powerful defect management. The defect management is not effective when the media are stored but when the are rewritten. They have an error correction comparable to standard DVD.
All rewritable media CD-RW DVD-RW DVD+RW and DVD-RAM use phase change technologies, which offer a limited change capacity.
KaTeker uses CD-R saving the full (master) backup data and CD-RW to save difference (update) backup data. The full (master) backup data is saved on the more reliable media. CD-R can hold reliable data up 100 years. This not true for each media and CR recorder. There are studies about the reliability of CD-R.
Now there are DVD-Recorder available supporting almost all DVD formats including DVD-RAM. First experiments with DVD showed, that DVD-RAM will become the favorite. It is easy to handle, uses a reliable technology.
The results are:
These rules are applicable to CD-R, CD-RW, DVD+-R and DVD-RAM
prefer CD-R, DVD-R and then DVD-RAM for long time saving data.
write DVD-RAM once for long time saving data.
use named media refer to http://www.cdrfaq.org.
use a CD recorder which supports recording speeds of 12 and higher
don't use slim recorder like those of notebooks
use media with media recording speed >= 4
use a recording speed of half the maximal media speed but not higher than 12 (10 gives good results)
store the media in a dark lightproof case or envelope
store the media at normal room temperature
handle the media with care (the label side is sensitive too!)
check the data on all media saving data for long time
© 2003-2004 Dr. Heiner Kuhlmann: www.dr-kuhlmann-software.de, kateker@dr-kuhlmann-software.de