iotop has been moved to being only allowable to be viewed as root.
iotop is a great program for measuring disk throughput and I am unable to figure the logic of why it has been moved to root-only. To be able to run
iotop as regular user again root permission must be given to the regular user for the program. A good way is to create a sudoers file per-user of allowable programs.
iotop can be invoked by (without need of a password):