Difference between failing and failed disks?

Question

Describe difference between failing and failed disks?

Answer 1

Failing disk

1) It illustrates read/write errors in /var/adm/messages.

2) As the time passes we can illustrates increased number of hard and transport error while checked by iostat -En.          

3) We can illustrates the disk accessible when format is used

Failed disk

1)It demonstrates “ disk not responding to selection” message

2)It only demonstrates the increased transport errors

3) Format command displays “disk is not available” message