Slowdown

$($a$)$ Jobs arrive at a server that services them in FCFS order:

FCFS

Theaveragearrivalrateis$\backslash$lambda $=12$ job$/$sec$.$Thejobsizes$($servicetimes$)$are independently and identically distributed according to random variable S$$where

$1$ with probability $3/4.2$ otherwise

S $=$

You have measured the mean response time: E $[$T $]=29.$

$12$

Based on this information, compute the mean slowdown, E $[$Slowdown$],$

where the slowdown of job j is defined as Slowdown$($j$)=$ T $($j$),$ where S$($j$)$

T $($j$)$ is the response time of job j and S$($j$)$ is the size of job j$.$

$($b$)$ If the service order in part $($a$)$ had been Shortest$-$Job$-$First $($SJF$),$ would the

same technique have worked for computing mean slowdown?