A keyboard connected to a computer is used at a rate of 1 keystroke per second. The computer system polls the keyboard every 10 ms (milli seconds) to check for a keystroke and consumes 100 $$\mu$$s (micro seconds) for each poll. If it is determined after polling that a key has been pressed, the system consumes an additional 200 $$\mu$$s to process the keystroke. Let $$T_1$$ denote the fraction of a second spent in polling and processing a keystroke.

In an alternative implementation, the system uses interrupts instead of polling. An interrupt is raised for every keystroke. It takes a total of 1 ms for servicing an interrupt and processing a keystroke. Let $$T_2$$ denote the fraction of a second spent in servicing the interrupt and processing a keystroke.

The ratio $${{{T_1}} \over {{T_2}}}$$ is __________. (Rounded off to one decimal place)

Which one of the following facilitates transfer of bulk data from hard disk to main memory with the highest throughput?

$$ * \,\,\,\,\,\,\,\,\,\,\,$$ Interrupt from $$CPU$$ temperature sensor (raises interrupt if $$CPU$$
$$\,\,\,\,\,\,\,\,\,\,\,\,\,\,$$ temperature is too high)
$$ * \,\,\,\,\,\,\,\,\,\,\,$$ Interrupt from Mouse (raises interrupt if the mouse is moved or a button is
$$\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,$$pressed)
$$ * \,\,\,\,\,\,\,\,\,\,\,$$ Interrupt from Keyboard (raises interrupt when a key is pressed or released)
$$ * \,\,\,\,\,\,\,\,\,\,\,$$ Interrupt from Hard Disk (raises interrupt when a disk read is completed)

Which one of these will be handled at the $$HIGHEST$$ priority?