what is set load ,set driven cell , set input delay and set out put delay

[mazouzi]

hi can any one expalin me

1) set_input_delay
2)set_output_delay
3)set_load
4)set_driving_cell

and why we use them !!

 

[rahul.achates]

set_input_delay is the time needed for tool to calculate timing on input.

set_output_delay - is the time needed for tool to calculate timing on output

set_driving_cell - This command specifies the drive capability of the input port in terms of a library cell. It indirectly limits the load seen on the input port.

set_load - This command specifies the external load that the output port must drive.