I ran following command on linux terminal
hdparm -T -t /dev/sda. It is not giving any output and i am unable to stop this by
ctrl+z. How to terminate this program with out restarting system?
Open another terminal and do a ps aux|grep hdparm to get the process id and then pass that process id to kill command. If you are sure that there is only one hdparm process that is running then you can do the following as well: