To examine the Exhibit， press the Exhibit button. While a developer is compiling a C program， "vmstat 120 10" is run to determine the cause of a performance problem.  Using the vmstat output as shown in the exhibit， which of the following conclusions is most appropriate to draw about the machine？（）

单项选择题Whichofthefollowingcommandsshouldbeusedtomonitorthenumberofbytesreadonanygivendisk？（）

A. tprof
B. topas
C. filemon
D. vmstat

单项选择题WhichofthefollowingstatementsisTRUEconcerningthepocolumnofthevmstatcommand？（）

A. The sys is high when po is high.
B. The po represents the number of page steals.
C. The low values usually indicate insufficient paging space.
D. The low values usually indicate sufficient memory for the load.

单项选择题Whilemonitoringasystemusingvmstat，whichofthefollowingoptionsmostlikelyindicatesthatthesystemisCPUbound？（）

A. r is greater than 40
B. id is greater than 50
C. sum of id and wa equals 50
D. sum of us and sy equals 100

单项选择题A typical example of a process # 19082 in the  proc file would be：      # ls -l  proc 19082      total 0   dr-xr-xr-x  1  root system 0    Sep 15  15：12  .      dr-xr-xr-x  1  root system 0    Sept 15 15：12  ..      -rw-------  1  root system 0    Sept 15  15：12 as       -r--------  1  root system 128  Sept 15  15：12 cred      --w-------  1  root system 0    Sept 15  15：12 ctl      dr-xr-xr-x  1  root system 0    Sept 15  15：12 lwp      -r--------  1  root system 0    Sept 15  15：12 map      dr-x------  1  root system 0    Sept 15  15：12 object      -r--r--r--  1  root system 448  Sept 15  15：12 psinfo     -r--------  1  root system 1024 Sept 15  15：12 sigact      -r--------  1  root system 1520 Sept 15  15：12 status      -r--r--r--  1  root system 0    Sept 15  15：12 sysent   Writing to which of the following files will allow the owner to stop a process？（）

A. status
B. sysent
C. ctl
D. as

单项选择题Inaniostatreport，whichofthefollowingoptionsbestdescribesthevalueof%iowait？（）

A. The amount of time taken to service an I/O interrupt
B. The percentage of time CPU（s） are waiting for page ins
C. The percentage of time the CPU9（s） are waiting on network
D. The percentage of time the CPU（s） are waiting for outstanding disk I/O requests