1. Mount and unmount cdrom
Mount: sudo mount /media/cdrom0 -o unhide
Forcefully Unmount: sudo umount /media/cdrom0 -f

3. Create ISO file: mkisofs -r -o file.iso  /location_of_folder
Generate MD5 checksum file: md5sum file.iso > file.iso.md5
Check MD5 checksum of file: md5sum -c file.iso.md5

4. Mount and unmount iso file:
Mount :
sudo mkdir /media/iso
sudo modprobe loop
sudo mount file.iso /media/iso/ -t iso9660 -o loop

Umount:  umount /media/iso