Infant mortality and longevity of DVD media?
Jerome H. Fine
jhfinedp3k at compsys.to
Fri Oct 5 16:26:24 CDT 2007
I have a specific question, but a general concern about how long a
backup can still be read.
I realize that all of the hardware and software is less than 10 years old,
but the software files being backed up are often 30 years old.
Environment: Pentium III (running W98SE) or Pentium 4
(running WXP) and using GHOST 7.0 as the backup software
with C: hard drive under FAT32 file structure. An image
file backup made of the C: drive is eventually written to
a DVD and within a time period of between one second to one
day, another copy of the DVD file is made back to a spare
hard drive thereby proving that the DVD can be read. In
addition, the MD5 value of the image file was kept and
written to the DVD and compared with the MD5 value of the
file copied from the DVD (since it takes less time to
produce the MD5 value from a hard disk file than from
an identical DVD file).
Question: How long a period of time should I wait to be
sure that infant mortality of the image file on the DVD
is no longer a factor? Is one second sufficient? i.e.
at present as soon as the DVD is finished being burned
and the DVD is ejected, I copy all of the files back to
a vacant partition on the hard drive.
Question: I am using Fujifilm DVD-R 16X 4.7 GB blanks
with an old Pioneer 105 DVD burner. I have not experienced
any problems over the past 5 years and I plug the power
into the DVD burner ONLY when it is being used - which
is 3 or 4 times a year. Should I be using a second
DVD drive which only reads a DVD to check on the files
which have been burned to the DVD blank? How often should
I be reading the files on the DVD to be sure that the
files can still be read? Is 5 years the length of time
before I should duplicate the files on an old DVD? Or
perhaps sooner or perhaps longer? Since I make and keep
a monthly backup image file of the C: drive (3 DVDs a year
with 4 monthly backup files of 1 GB each), loosing one
backup image file would probably not be critical.
Question: The dual layer DVD drives and blanks (which
hold more than 8 GB) seem to be more than double the cost.
Are they just as reliable at this point as the single
layer drives and blanks which hold only 4.7 GB?
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