In order to determine how efficiently an application is reading and writing data， which of the following utilities will report read and write sizes on disk I/O requests？（）

单项选择题To examine the Exhibit， press the Exhibit button. While a user 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 I O bottleneck？（）

A. The bottleneck is network I/O.
B. The bottleneck is local disk I/O.
C. The bottleneck is paging space I/O.
D. The bottleneck is to a remote filesystem.

单项选择题WhichtoolisbasedontheAIXtracefacility？（）

A. no
B. netpmon
C. entstat
D. nfso

单项选择题Whichofthefollowingcommandsshouldbeusedtotuneparametersofdevicesthataredisplayedwithlsattr？（）

A. chdev
B. cfgmgr
C. vmtune
D. schedtune

单项选择题Whichofthefollowingcommandsshouldbeusedtoidentifypacketsequenceproblems？（）

A. ping and arp
B. lsattr and ifconfig
C. netstat and iostat
D. iptrace and tcpdump

单项选择题InAIX5Landlater，theoperatingsystemsupportsthe procfilesystem.Whatwouldbethebestdescriptionofthe procfilesystem？（）

A. It is a pseudo filesystem that maps processes and kernel data structures to corresponding files.
B. It is a JFS mounted filesystem that provides an exact representation of what is happening to a proces at a single and discrete point of time.
C. It is a JFS mounted filesystem that maps processes and read-only files related to these processes.
D. It is a pseudo filesystem that contains data that represents the state of the parent processes （but not their threads） in a system.