Q$\mathrm{.}5.$ I$/$O Issues $[25$ marks$]$

Suppose that you are designing a game system that responds to players' pressing

buttons and toggling joysticks. To meet users' needs you need to improve overall

system speed by $50\%.$ You know that these $\frac{\frac{?}{?}}{O}$ events account for $75\%$ of the

system workload. You figure that a new I$/$O interface card should do the trick. If the

system's existing I$/$O card runs at $10kHz($pulses per second$),$ what is the minimum

speed of the I$/$O card that you need to order from the supplier?

$[5$ marks$]$

Answer

Of the three methods: programmed $\frac{\text{I}}{O},$ interrupt$-$driven $\frac{\text{I}}{O},$ or DMA, which is more

suitable for processing the $\frac{1}{O}$ of $a$ :

a$)$ Mouse

b$)$ Game controller

c$)CD$

d$)$ Memory stick

You may choose more than one answer for each device. Explain your answers.

$[8$ marks$]$

Answer

Suppose you have a $100$ GB database housed on a disk array that supports a

transfer rate of $60M\frac{B}{s}$ and a tape drive of $200GB$ capacity with a transfer rate of

$80MB$ per second.

a$.$ How long will it take to back up the database to the tape?

b$.$ What is the transfer time if $50\%$ compression at the tape drive is possible?

Assume that the tape is mounted, and no errors occur.

$[12$ marks$]$

Answer