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Re: sarge cd integrity check



On Wednesday 06 April 2005 00:22, Joey Hess wrote:
> peter colton wrote:
> >   For your reply, The reason I want to check the integrity of the cd or
> > dvd after a burn. Is that I have found out that a good burn "no buffer
> > under run" dose not mean that the image is OK. By checking the image with
> > the md5sum -c md5sum.txt  that is on the iso I am then certain that the
> > product is correct. The method of dd the image off I will be looking
> > into.
>
> The problem with the md5sum -c check is that it only checks the files
> themselves and not the full filesystem. It might miss things to do with
> the el torito bootable part of the CD, for example.


 hello joey

  Thanks for the pointer to using dd as the integrity check method. I have use 
isoinfo -d -i /dev/hdx to find out the info I need to use dd to copy just the 
image from the drive. Logical block size is:  Volume size is: . Then with 
this info I set up dd . 

 dd if=/dev/hdX bs=Logical block size count=Volume size  of=sarge-i386-1.iso

The when I have dd the image back to the drive I run the original md5sum file 
on this image again. and bingo perfect. I have all so tuned up the system 
with hdparm. enable 32 bit and dma on hard drives and burns. this as made a 
big difference for the burning speed. Before enabling 32 bit and dma. Four 
speed burning was turning out as two speed. now with the formentioned, four 
speed is four speed.

All so as part of my learning curve I have seen that dvd or cd media quality 
plays a major part. I was using unbranded media and with very poor turn out 
rate of good burns. Then next a low brand RITEK and good turn burn rate.  Now 
I am looking at using datawrite white tops median, So I am now seeing the 
trees from the woods more. thanks.


                           bye for now

                                peter colton  

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