A given processor requires $1500$ cycles to perform a context switch and start an interrupt handler $($and the same number of cycles to switch back to the program that was running when the interrupt occurred$),$ or $500$ cycles to poll an I$/$O

device.An I$/$O device attached to that processor makes $200$ requests per second, each of which takes $12,000$ cycles to resolve once the handler has been started. By default, the processor polls every $0\mathrm{.}4ms$ if it is not using interrupts.

a$.$ How many cycles per second does the processor spend handling I$/$O from the device if interrupts are used?

$(1\mathrm{.}5)$

b$.$ How many cycles per second are spent on I$/$O if polling is used $($include all polling attempts$)?$ Assume the processor only polls during time slices when user programs are not running, so do not include any context$-$switch time in your calculation.

$(3)$

c$.$ How often would the processor have to poll for polling to take as many cycles per second as interrupts?

$(2\mathrm{.}5)$