I don't make ISO imges from CD or DVD that often but once in a while, I need to do this. So, to remind myself, here is the steps.
The information in this site is the result of my researches in the Internet and of my experiences. This information below is solely used for my purpose and may not be suitable for others.
1) Use isoinfo to find block/volume sizes
Gentoo Linux does not come with isoinfo, so it needs to be installed.
# emerge --ask app-cdr/cdrtools
# isoinfo -d -i /dev/sr0 | grep -i -E 'block size|volume size'
Logical block size is: 2048
Volume size is: 1327235
- -d: Print information from the primary volume descriptor (PVD) of the iso9660 image.
- -i: Specifies the path of the iso9660 image to examine (/dev/sr0).
- -i: Ignore cases.
- -E: Interpret 'block size|volume size' as extended regular expressions.
2) Use dd to create an ISO image
# dd if=/dev/sr0 of=<name_of_image>.iso bs=<block_size_from_above> count=<volume_size_from_above> status=progress