Describe how Direct Memory Access $($DMA$)$ works. $(10$ points$)$

a$.$ Explain the NUMA multiprocessing architecture. $(5$ points$)$

b$.$ What advantage does it have over multicore SMP systems? $5$ points$)$

Consider a computing cluster consisting of two nodes running a database.

a$.$ Describe the two ways in which the cluster software can be structured.

$(10$ points$)$

b$.$ Discuss one benefit and one disadvantage of each. $(10$ points$)$

$6.$

a$.$ What is the purpose of interrupts? $(5$ points$)$

b$.$ How does a hardware interrupt differ from a software interrupt? $(5$

points$)$

Explain how the Linux kernel variables HZ and jiffies can be used to

determine the number of seconds the system has been running since it was

booted.

You can use an example e$.$g$.$ Given $5$ HZ and $20$ jiffies, here is how I can

determine how many seconds have elapsed since my system started running.

Then explain your reasoning behind your process and show your calculation

$(15$ points$)$

Rank the following storage systems from slowest to fastest:

a$.$ Hard$-$disk drives

b$.$ Registers

c$.$ Optical disk

d$.$ Main memory

e$.$ Nonvolatile memory

f$.$ Magnetic tapes

g$.$ Cache

$(35$ points; $5$ points for each correct placement$)$