Processes p$1$ and p$2$ execute on a system with a single CPU and $2$ identical I$/$O devices. Each process executes

a compute$-$bound phase followed by an I$/$O$-$bound phase. The system uses multiprogramming without time$-$

sharing. The following table shows the lengths of each phase.

p$1$ starts first at time $0.$

Without multiprogramming, the computation terminates at time

With multiprogramming, the computation terminates at time