数据库系统工程师考试大纲|数据库系统工程师模拟试卷（1上）3

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●某循环冗余码(CRC)的生成多项式为G(X)＝x5+x4+x+1，则它对任意长度的信息位产生＿(61)＿位长的冗余位，并可检验出所有突发长度＿(62)＿位的突发错误。若信息位于1010100，采用此生多项产生冗余位，加在信息位后形成的码字是＿(63)＿。在读出或接收端读到的码字中若不满足某种规律可判断其必然有错。例如＿(64)＿和＿(65)＿就是出错的码字。

　　　　(61)A．小于等于4　B．4　C．小于等于5　D．5　E．大于等于5　F．大于5

　　　　(62)A．小于等于4　B．4　C．小于等于5　D．5　E．大于等于5　F．大于5

　　　　(63)A．1010110111111　　　　B．1010111010001

　　　　　　C．1010110001101　　　　D．1010111101010

　　　　　　E．1010111011001　　　　F．1010110001100

　　　　(64)A．1010110111111　　　　B．1010111010001

　　　　　　C．1010110001101　　　　D．1010111101010

　　　　　　E．1010111011001　　　　F．1010110001100

　　　　(65)A．1010110111111　　　　B．1010111010001

　　　　　　C．1010110001101　　　　D．1010111101010

　　　　　　E．1010111011001　　　　F．1010110001100

　　●Typically,these are concerm with the establishment of ＿(66)＿ the network and with the control of the flow of messages across this channel. The provision of such facilities is only part of the network requirements,however,since in many applications the communicating computers may be of different types. This means that they may use different programming languages and,more importantly,different forms of ＿(67)＿ interface between user(application) prograrma，normally referred to,as application processes or APs,and the underlying communication services may be ＿(68)＿ For example，one computer may be a smaall single- user computer,while another may be alarge ＿(69)＿ system.In the earlier days of computer communication,these issues meant that only closed communities of computers(that is,from the same manufacturer) could communicate with each other in a meaningful way. IBM"s Systems Network

　　Architecture(SNA) and DEC"s Digital Network Architecture (DNA) are just two examples of communication software packages produced by manufacturers to allow their systems to be int ercormected together.These proprietary packages, however, of which there am still many inexistence, do not address the problem of universal interconnect ability, or open systems interconnection. In an attempt to alleviate this problem,＿(70)＿,in the late 1970s,formulated a reference model to provide a common basis (or the coordination of standards developments and to allow existing and evolving standards acivities to be placed into perspective with one another.

　　　　(66)A．communication channel access　　B．protocols

　　　　　　C．datachanneI　　　　　　　　　　 D．public communieation

　　　　(67)A．database　　　　　　　　　　　　B．data representation

　　　　　　C．protocols　　　　　　　　　　　 D．data communication

　　　　(68)A．same　　　　B．similar　　C．different　　 D．dependent

　　　　(69)A．multi-user　B．client　　 C．server　　　　D．full-user

　　　　(70)A．DNA　　　　 B．SNA　　　　C．the OSI　　　 D．the ISO

　　●One of the functions of the ＿(71)＿ is to store the applications progrms {or the various secondaries. The ＿(72)＿ may have similar or dissimilar functions. The same control code received from two different secondaries may warrant two different actions on the part of the host computer. If the system so requires,the host computer must also provide ＿(73)＿ for the centralized data and the software for database management. Data information is normally stored in auxiliary memories to which the computer has ready access. The＿(74)＿ peripherals connected to the host computer allow for human entry and intervention. As needs change, application programs may require additions, deletions, or changes. Data link problems also arise which are __(75)＿ the range of the computer"s programmed capabilities. In such cases, human entry is required to make the necessary changes to resolve the existing problems.

　　　　(71)A．peripherals　　B．host computer　　C．the interface　　D．the client

　　　　(72)A．set　　　　　　B．host　　　　　　 C．secondaries　　　D．record

　　　　(73)A．storage　　　　B．data　　　　　　 C．range　　　　　　D．link

　　　　(74)A．peripherals　　B．database　　　　 C．the interface　　D．clients

　　　　(75)A．dose to　　　　B．during　　　　　 C．within　　　　　 D．beyond

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