So I'd like to checksum my Debian 9.0 installation DVD to be able to compare it to the respective .iso file's hashes and the published hashes to be able to verify my installation's integrity.
I burned the Debian installation .iso to DVD under Ubuntu. There it had a problem verifying the DVD's checksum as it didn't proceed anymore at around 50% with the time remaining only rising and rising. However this may due to the fact that I accidentally executed sha512 (it had an error and didn't seem to have modified the .iso) instead of sha512sum on the .iso file during burning or checksumming. (The sha512 hash of the .iso was correct.)
I'd like to use sha512 and it seems I need the blocksize in bytes of my DVD first.
These 2 questions help but do not solve this issue for me: