On 04/01/2015 11:40 PM, Robin Laing wrote:
On 2015-04-01 19:15, g wrote:
> On 04/01/2015 02:18 PM, jd1008 wrote:
>> After burning 3 DVD's, and reading them back to compute sha256sum.
>> all three of them generated these error messages during readback,
>> and all 3 messages show the error was past the 4gb offset.
>>
>> Is this a media issue or is it the burner?
>
> 1- burn dvd at 2 speeds lower than what you used and had failure.
>
> if ok, problem is either burner or blanks.
>
> 2- burn dvd at failure speed on a different burner.
>
> if ok, get a new burner. if failure, may be blanks.
>
> 3- try different program or burn from command line.
>
>> A side question: why does the block io layer assume that all media
>> have 512 byte sectors?
>
> i believe that is a carry over from disk formatting started by the
> IBM PC. [do not hold me to that]
>
Also watch power supply voltages.
I have ran into two power supplies that caused issues with CD
burning. Couldn't supply that little extra bit of current during
the burn process. To burners later, I finally found it.
this is true.
a few years back, a poster asked for recommendations on building up
system and had a lot of responses.
my response of getting a power supply with at least a 20% factor,
and that a 30% factor would be even better due to my considering
future additions or changes.
i was met with opposition and even ridicule from a poster who
stated that he had never seen need.
too many 'builders' are unaware of such factors and will end up
with a system that gets flaky when additions and upgrades are
made.
such is a prime reason for 'ready made' failures.
back to dvd checksum errors and a great surprise that i just had.
due to need for centos 6.6 i386 for a system that i am putting
together for home control use, i decided to burn the iso to a
dvd rw disk using k3b and all went well including k3b ok'ing
the burn.
after closing k3b i ran 'sha256sum /dev/sr1 > sr1' with disk still
in the usb drive i burned it with. checksum failed.
so decided to moved disk to the internal burner to see how it check.
'sha256sum /dev/sr0 > sr0' produce correct sha256sum.
having run check on the usb burner many time before when using k3b
and cl and i have gotten good checks, i was surprised.
am i going to worry about it. hell no. 2 out of 3 good checks tells
me that Murphy is at it again. ((GBWG))
--
peace out.
in a world with out fences, who needs gates.
CentOS GNU/Linux 6.6
tc,hago.
g
.