the lack of a feedback
the presence of a feed back
the lack of a computer
the presence of a computer
第1题：
第2题：
Which of the following system utilities would be used to change a drive type from dynamic tobasic?（）
第3题：
第一组
An automatic system usually consists of a control system and an information system. A control system is a system which measures the condition of some entity and, with the information, governs the state of a variable; i.e., speed, temperature, pressure, position, etc. The open-loop system is the simplest form. a control system may assume. It is distinguished from the closed-loop system by the lack of an input which measures the state of the controlled variable; such an input is called a feedback. In modern ships the open-loop system has practically disappeared and the closed-loop system which operates with a feed-back is extensively used. An information system serves the parallel function of monitoring system or plant performance. The monitoring function may serve a number of purposes; specifically it may indicate values of controlled variables to guide remote control operations, warn of off-limit conditions and provide record of performance. In many cases a visual and audible alarm may be provided to warn of off-limit conditions on board ship and, associated with this, the important variables will be recorded on demand. The automatic control system can be more sophisticated by incorporating digital-processing equipment, that is, a computer. This computer is usually fed with signals from all sensors. It scans the values of the sensors and generates alarm signals for off-limit conditions, acting as a super-supervisor. Sometimes, it can even make necessary and take the necessary action to optimize performance without human intervention.
The closed-loop system differs from the open-loop system by
A.the lack of a feedback
B.the presence of a feed back
C.the lack of a computer
D.the presence of a computer
第4题：
设置PDCCH信道是否使用发射分集的参数是（）
第5题：
You need to restore some files from a file system. The file system was backed up from a snapshot. Which command will correctly restore these files？（）
第6题：
第7题：
The system administrator did a new install of AIX on a server about a week ago. The system was not rebooted after the installation. CDE is running on this system as is TCPIP. The system administrator has started configuring the system percompany directives. The power cable was inadvertently disconnected from the wall causing the sever to lose power. Upon reboot, the system appears to hang during log in from the console or from Xterminals. Which of the following is the most probable cause?（）
第8题：
第9题：
You need to increase the size of a paging file. What should you do? （）
第10题：
设置PDCCH信道是否使用发射分集的参数是（）。