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Re: tapes best for backup?

Douglas A. Tutty wrote:
On Sat, Jan 05, 2008 at 03:12:31PM -0600, Hugo Vanwoerkom wrote:
Douglas A. Tutty wrote:
On Sat, Jan 05, 2008 at 02:53:45AM -0500, Rick Thomas wrote:

As a registered pack-rat, I've got a drawer full of similar old CD- Rs. If I get ambitious and I've got some free time, I'll try a bunch more, just for fun...
I wonder what cdck would show.  It tests not only ability to read the
files, but counts any otherwise silent errors as well.  It also
automates the reading every file process.

Curious little program: none of my CD-R's are rated anygood. Use them all the time. Maybe it has problems with the disk "ends". Clearly I'm a user, not a developer.

I use it to check all my CD-Rs intended for backup before I consider
them done.  The program is supposed to be able to verify track layout to
predict its readability by other drives, and the strength of the signal
to predict its longevity.
I've never seen cdck say a disk wasn't "anygood", just "excellent" or, I
believe, "satisfactory".  I tend to get  "satisfactory" if I use a fast
burn speed (e.g 16x) and "excellent" if I use a lower speed (e.g. 4x),
even though the buffers are shown to never have been emptied.  I wonder
if the drive slowing down the burn to prevent a buffer under-run can
cause problems that cdck can detect.

What I get is:

/Sun Jan 06-07:52:00SDA6# cdck
Reading sectors 1-302
4 ok
248 ok
! unable to read sector 302, reason: Input/output error

CD overall:
   Sectors total: 302:
   Good sectors: 248:
   Bad sectors (incl. with poor timing): 54
CD timings:
   Minimal = 2 usec (0.000002s)
   Maximal = 1252828 usec (1.252828s)
   Average = 5824 usec (0.005824s)

   Disc contains BAD or even readable sectors, put it into trash can!
/Sun Jan 06-07:52:09SDA6# exit

But that is my grub boot CD that I use every day and just yesterday recreated it.


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