An ISO is a disc image of an optical disc, such as a CD, DVD, or Blu-ray disc. It contains all the data on the disc, including the file system and boot information. An ISO file can be used to create a bootable USB drive or DVD, which can then be used to install an operating system.
Linux Debian is a free and open-source operating system that is based on the Debian distribution. It is popular for its stability and security, and it is used by a wide range of users, from home users to businesses.