At 7:38 PM -0700 1/1/07, Charles Curley wrote: >Content-Type: multipart/signed; micalg=pgp-sha1; > protocol="application/pgp-signature"; boundary="BghK6+krpKHjj+jk" >Content-Disposition: inline > >On Tue, Jan 02, 2007 at 01:17:24PM +1100, Danny Yee wrote: >> Peter Gordon wrote: >> > Each ISOs directory contains a file called SHA1SUM that contains the >> > SHA-1 hashes of the images. You can use a tool called sha1sum to >> > calculate this hash from the image and compare it to the content of the >> > SHA1SUM file. >> >> I wanted to check the burn, not the download. But your message gave >> me half what I wanted. >> >> I ended up doing the following >> >> * looked at how big the iso image was and divided that by 512 to get >> the number of blocks in it >> * dd if=/dev/dvd of=check.iso count=blocks >> * sha1sum check.iso >> * compared that with the SHA1SUM file > >"sha1sum /dev/dvd" would have saved you a step. In Unix or Linux, >everything is a file. Everything. ... This gives a different checksum than the command below, which gives the correct checksum. Checking extra 0's at the end of the DVD changes the sum. []# dd if=/dev/dvd bs=2048 count=`isosize -d 2048 /dev/dvd` | sha1sum AIUI, even this can fail due to the kernel readahead bug. Sometimes it is necessary to read the ISO into a file and trim it to the correct size. See Paul Howarth's isograb script at <http://www.city-fan.org/tips/IsoImageFromMedia>. -- ____________________________________________________________________ TonyN.:' <mailto:tonynelson@xxxxxxxxxxxxxxxxx> ' <http://www.georgeanelson.com/>
