NOHUP - ignore the HUP (hangup) signal. POSIX Compliant.
When using the command shell, prefixing a command with nohup prevents the command from being aborted automatically when you log out or exit the shell.
DISOWN - relinquish job from shell job management. disown can be used after a command has been launched while nohup must be used before. Not POSIX.
The job remains connected to the terminal but is no longer listed in the job table.