Hello William,
I would confirm that. I'm using an old USB Backpack CDreWriter at 4x,
and it's flawless. It never seems to fail, where my faster burners
often seem to skip a beat. I've managed to get all the iso's burnt
without problem and have successfully installed from them.
--
Best regards,
Mickael
mailto:mike@xxxxxxxxxxxxxx
Friday, March 4, 2005, 7:26:26 AM, you wrote:
WW> I burned the cd iso's at either 10x(hp) or 32x(nec) without
WW> issues using verbatim and maxell cd-r's. I burned the dvd's with
WW> the nec at 8x on maxell media without issues.
WW> Maciej ?enczykowski wrote:
>> I just burned 3 CD's (at speed 16 on a 40x capable burner) of "CentOS4
>> i386-bin CD1" (md5sum of image on HDD is OK, after padding it changes but
>> who cares)
>> One straight from iso, the other with appended 300KB zeroes, the third
>> with cdrecord -pad.
>>
>> CD A: iso
>> CD B: iso with builtin 300KB pad (150 sectors of 2KB, IMHO 15 is enough)
>> CD C: iso with cdrecord -pad (15 zeroed sectors of 2KB = 30KB)
>>
>> cmp -l /dev/cdrom file.iso-unpadded
>> CD A: IO error (within the last 30KB)
>> CD B: EOF on file.iso
>> CD C: EOF on file.iso
>>
>> cmp -l /dev/cdrom file.iso-prepadded
>> CD B: OK
>> [wonder why I'd expect an
>> IO error (within the last 30KB of the padded image)]
>>
>> running md5sum on CD A/B gives IO ERRORS, while C works (think this was
>> just a matter of luck).
>>
>> My theoretical explanation which isn't perfect:
>> Why? Cause the burner can only burn in 32KB blocks (16 sectors) and
>> anything leftover doesn't burn (is left of the disk, so it can't be read)
>> (my drive: [LITE-ON ][DVDRW SOHW-832S ][VS0A])
>>
>> CD A: Mediacheck FAIL
>> CD B: Mediacheck OK
>> CD C: Mediacheck OK
>>
>> This proves pre-padding CD iso images before distribution with a few (30KB
>> at least, 300KB suggested) KB worth of zeroes fixes burn issues and
>> retains a working mediacheck - even if the last part of the burned image
>> is unreadable (since it'll be in the unimportant padding...)
>>
>> Thus images should be padded after implanting the md5sum and before
>> calculating the md5sum for distribution.
>>
>> ie.
>> mkisofs > file.iso
>> impland-md5iso file.iso
>> dd if=/dev/zero bs=2048 count=150 >> file.iso
>> md5sum file.iso > MD5SUMS
>> upload file.iso MD5SUMS
>>
>> Cheers,
>> MaZe.
>>
>> On Thu, 3 Mar 2005, Maciej ?enczykowski wrote:
>>
>>
>>>I'm pretty sure we should just prepad the ISO's with 300KB worth of zeroes
>>>before calcing their md5sums and distributing them, I'll check whether
>>>this works (what's a CD worth? 30cents?) in a moment and report back.
>>>If this only passes mediacheck (all reports are it should) then this will
>>>eliminate _all_ non-badburner and bad-media related burn errors (some 95%
>>>I'd say) and save a lot of trouble for a lot of people (ie I wasted a CD
>>>and 10 minutes burning the 4 centos4 cd's).
>>>
>>>Cheers,
>>>MaZe.
>>>
>>>On Thu, 3 Mar 2005, Collins Richey wrote:
>>>
>>>
>>>>On Thu, 3 Mar 2005 14:27:02 -0500, Lamar Owen <lowen@xxxxxxxx> wrote:
>>>>
>>>>
>>>>>This is my last post on the subject since people seem to be more interested in
>>>>>splitting hairs than in helping people get a good burn on their hardware.
>>>>>And whether their hardware is broken or not is irrelevant; there is a
>>>>>recommendation that works for the vast majority of people that have the
>>>>>problem, and I simply looked through my archives to try to help people get a
>>>>>good burn. If I had known that people were going to nitpick my post I
>>>>>would not have bothered looking through my archives, nor would I have
>>>>>posted it.
>>>>>--
>>>>
>>>>Please don't consider my questions on the subject "nitpicking." I'm
>>>>just enterested in learning "the rest of the story," most especially
>>>>since it runs counter to several years of my own experience.
>>>>
>>>>Thank you for replying at length. Helping people to understand "why"
>>>>is somethimes just as important as understanding "how" or "what."
>>>>
>>>>
>>>
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>>>http://lists.caosity.org/mailman/listinfo/centos
>>>
>>
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>>
