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Re: Failure of DVD/CD RW drives

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On 04/18/2015 02:08 PM, Bit Twister wrote:
> On Sat, 18 Apr 2015 12:48:37 -0700, Bobbie Sellers wrote:
>
>> 	This past week the activity level had resolved itself and I
>> had time spare to test the disks I had made.All but one failed so
>> I thought I better make them again and the new batch was just as
>> bad.
>
>
> I suggest you could script your copy activities and test/verify that
> each burn was ok/valid.

	That sounds fine on the face of it but none of the disks
would mount and that started as soon as the burn was done.
	Also on Knoppix Klaus Knopper prefers
to keep the sums private and for people to use the command
"testcd" when the disk boots.
	the following is quoted from a response from Klaus Knopper
>
> If you start Knoppix with
>
> knoppix testcd
>
> the main files for Knoppix will be checksummed and compared with
> KNOPPIX/sha1sums.
>
> Since the size of the resulting ISO file will most likely differ from my
> copy when you just copy the DVD to a file (padded by some zero blocks),
> it makes no sense to run a sha1sum or md5sum over the iso itself. Also,
> Linux Magazine may have changed some of the DVD contents, like boot help
> or included help files. Just checking against sha1sums should be
> sufficient to make sure the Knoppix file system os OK.


	Thanks for the code example.  I will file it and if I ever get a call 
for a lot of disks other than the Knoppix I will try to implement
it.

>
> example:
>
>             #*******************
>             #* get image md5sum
>             #*******************
>      set $(md5sum $_iso_fn)
>      _iso_sum=$1
>
>             #***************
>             #* burn image
>             #***************
>      cdrecord -v gracetime=3 dev=$_dev -sao -data $_iso_fn
>      if [ $? -ne 0 ] ; then
>        echo "cdrecord burn failure on $_iso_fn"
>        exit 1
>      fi
>
>      _iso_bytes=$(stat $_iso_fn -c %s)
>      _sectors=$(( $_iso_bytes / 2048 ))
>
>             #************************
>             #* get burnt media md5sum
>             #************************
>      set $(readcd sectors=0-$_sectors dev=$_drive f=- | md5sum)
>      _cd_sum=$1
>
>
>      if [ "$_cd_sum" != "$_iso_sum" ] ; then
>        echo "md5sum mismatch for $_iso_fn"
>      fi
	

	bliss

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Thread

Failure of DVD/CD RW drives Bobbie Sellers <bliss-sf4ever@dslextreme.com> - 2015-04-18 12:48 -0700
  Re: Failure of DVD/CD RW drives Bit Twister <BitTwister@mouse-potato.com> - 2015-04-18 21:08 +0000
    Re: Failure of DVD/CD RW drives Bobbie Sellers <bliss-sf4ever@dslextreme.com> - 2015-04-18 15:08 -0700
      Re: Failure of DVD/CD RW drives faeychild <faeychild@nomail.afraid.org> - 2015-04-19 10:50 +1000
        Re: Failure of DVD/CD RW drives Bobbie Sellers <bliss-sf4ever@dslextreme.com> - 2015-04-18 19:35 -0700
          Re: Failure of DVD/CD RW drives Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-04-19 17:52 +0000
            Re: Failure of DVD/CD RW drives Bobbie Sellers <bliss-sf4ever@dslextreme.com> - 2015-04-19 12:34 -0700

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