Linux (Ubuntu) make an ISO image of a CD or DVD in one step

Two frequent recommendations made online for creating ISO images are to use dd or cat e.g. For example:

dd if=/dev/cdrom of=cdimage.iso

OR

cat /dev/cdrom > cdimage.iso

Neither are appropriate to create an image of CD or DVD.

1. They provide no error checking and require a hash checksum such as MD5 or SHA1 to verify the image created is true to the original media; and
2. Neither dd or cat lock the underlying files so there's a risk they could change whilst the image is being created.

Use readom...