iso images
hello everybody!
my name's max and i'm new on this list.
i'd like to post a question which i think will be interesting, at least for
us newbies :)
i finally rsync'd the pseudo images for potato binary-i386-1_NONUS.iso and
binary-i386-2.iso and they checked the md5sums all right.
then i burned the first image under win98 with nero as described in
http://cdimage.debian.org/faq.html and all seemed ok; i even successfully
booted the cd.
i still had the .iso file on the hd, and was thinking about deleting it...
but a sudden doubt arose: would it be possible to recreate the exact iso
image from the burned cd?
i fired up linux (i use slackware 7.1 at this time), ripped the cd this way:
dd if=/dev/hdb of=image.iso
then i waited some time...
i got an i/o error but i did not bother (someone told me not to) and
surprise! the image.iso i obtained was ok, as i was able to mount it
(with -o loop option) and see the files in it but... the dimension in bytes
was different from the original image i downloaded... and obviously the
md5sum didn't match.
how could i be sure that the image i ripped was good? or, for that matter,
that the cd burn had gone ok?
i repeat: the cd was readable and bootable, and the ripped image.iso was
mountable and readable.
then i thought: maybe it's win98 and nero's fault. let's do it all in linux.
so i fired up cdrecord, burned the second image (binary-i386-2.iso) like
this:
nice --18 cdrecord -eject -v speed=8 dev=0,0,0 -data -pad binary-i386-2.iso
as was told in http://cdimage.debian.org/faq.html and then i mounted the
obtained cd, looked a bit in it and the files were there; then i ripped it,
this time (being lazy) using this:
cat /dev/hdb > image.iso
again i/o error but a perfectly mountable iso9660 image... but again NO
MATCH IN BYTES DIMENSION, namely:
binary-i386-2.iso: 665292800 bytes
image.iso: 665323520 bytes
so.
1) how can i be sure everything is ok before deleting the downloaded images?
2) how can i rip a new iso9660 image from a burned cd that is exactly
identical to the original image, so the it checks against the size AND
md5sum of the original image?
i was forgetting a detail, maybe it's important: the original images are in
a win98 partition that i mounted from linux with mount -t vfat etc... so all
the operations i described (cdrecording, md5summing, and size checking) were
made with such an arrangement (but i don't think it matters as filesize is
concerned, right?)
ok, i hope that someone gets my message and is willing to help.
thank u people.
bye.
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