On Mon, 2007-04-23 at 05:00 +0200, Maciej Zenczykowski wrote:
> My suggestions:
>
> verify the md5sum's / sha1sum's of the burned CD/DVD's. (Since you
> already have the apparently correct iso downloaded to disk). How?
>
> like this:
>
> dd if=/dev/dvd bs=xxx count=yyy | md5sum
>
> (/dev/dvd is your dvd/cd whatever device, might be /dev/cdrecorder,
> /dev/cdrw, /dev/dvd, /dev/dvdrw, /dev/hda, /dev/hdb, /dev/hdc, /dev/hdd,
> etc... you should know ;-) )
>
> Where xxx and yyy satisfy the constraint xxx * yyy = size of iso image in
> bytes. Preferably you want xxx as large as possible. Since iso's are
> written in 2KB sectors, you can always use 2048 for xxx, but bigger is
> better (better = faster).
>
> If I've lost you, then just do:
Nope, not lost! Been doing lots of *IX things for more decades than I
wish to confess publicly! :-)
I had considered that and discarded it due to the statements by Joerg in
his docs about the problems with kernels >=2.5. BTW, I've since looked
at the logs and confirmed that kernel buffer errors (I think) occur and
get the kernel complaining about I/O errors on /dev/hdc (the drive I was
going to checksum the CDs on on CentOS). I'll give the dd a try with a
blksize of some multiple of 2K and see if that gives me a decent
checksum.
> <snip>
> This will allow you to do a mediacheck by hand. I'd venture to guess
> they'll fail... if so, then burn on good media at minimum speed (ie. like
> 1x, or 2x, or something) - although I know you've tried this... I'll just
> add my 2c - I burnt the DVDs with no problem at 4x, and the above
> mentioned verification passes.
Let's start an office pool! I'm betting they'll pass because the media
are not that old and and have been successfully used previously. I'm
betting on the Linux kernel problems mentioned Joerg as being guilty
when a high-speed sequential pass is made to do the checksum.
And you are right, I did burn at lower speed. *sigh* didn't help. I
think I've got an old 2.4* kernel laying around on one of my HDs that
I'm waiting to (re)install and use again. If I burn it there, I'll
probably get good results.
>
> Cheers,
> Maciej.
> <snip sig stuff>
Thanks for the feed back and thoughts.
For John Summerfield, thx to you to. I had been considering doing the
network install, but I'm always meandering around and tearing
down/(re)building my home eqpt. There is a certain sense of security
that comes with having known good media available in case the current
torn-down unit is my server (I know, I've got enough old junk around,
why don't I have multiples yet? Time, incentive, trying to get my skills
updated to current levels vis-a-vis admin and user things).
I had also thought of "don't do the media check, but decided to first
prevail upon the wisdom, and potential humor, of the list.
Mr. Kiwi, also thanks for taking the time. Combined with John's thought,
I will feel giving the "install regardless" attempt a shot will be
worthwhile.
Thanks to all. I'll post a "SOLVED" to end this thread if any/all of
these things work. maybe the next "victim" achieves "nirvana" is
significantly less time, with less angst, that way.
Probably take a day or two to take a shot at it. I quit working
professionally with this junk a long time ago and now have to actually
*work*, rather than play, for a living.
Thanks to all,
--
Bill
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