[全国计算机等级考试四级含金量]2017年全国计算机等级考试四级模拟试题(四)

　　(67) How many key comparisons occur in searching for key 35 in the given hash table? (2分)
　　 A) 0 B) 1 C) 2 D) 3
　　
　　 (68)& If a new key 67 is inserted into the given hash table, what will be its address? (2分)
　　 A) 3 B) 4 C) 5 D) 6
　　
　　 (69) Suppose the contents of the DOS IF1.BAT file on the hard disk is as follows.
　　 @ECHO OFF
　　 MEM>FILE1
　　 SORTFILE2
　　 DEL FILE1
　　 @DATE
　　 @TIME
　　 IF EXIST %1 ECHO % IF FOUND
　　 If all of the commands are successfully executed after IF1 FILE1 is
　　 typed, then the screen displays?
　　 A) None B) Date and time C) FILE1 IS FOUND D) FILE2 IS FOUND
　　
　　 (70) If the files in the current directory are
　　 aac, abc, acb,acc, aca, ao, al, a2, ab, ac, aa,
　　 and the command ls a?[bc] is executed, how many files will be listed?
　　 (2分)
　　 A) 3 B) 4 C) 5 D) 6
　　
　　 (71) In order to append a standard output to an existing file, which of the following operators is used in the UNIX system?
　　 A) | B) & C) > D) >>
　　
　　 (72) Consider the following figure, where the shaded parts represent already assigned blocks of memory, and the unshaded parts represent free blocks. (2分) If there is a request for 40KB of memory and the best-fit algorithm is used, then the beginning address of memory that is allocated in response to the request is
　　 A) 100KB B) 190KB C) 330KB D) 410KB
　　
　　 (73) On a certain disk, there are 200 tracks, numbered 0-199, the current position of the disk head is track 53. If the shortest-seek-time-first scheduling algorithm is used when the tracks
　　 98, 183, 37, 122, 14, 124, 65, 67
　　 are requested, then the head-moving sequence that results will be (2分)
　　 A) 65, 67, 37, 14, 98, 122, 124, 183
　　 B) 65, 67, 37, 98, 122, 124, 183, 14
　　 C) 65, 67, 98, 122, 124, 183, 37, 14
　　 D) 98, 183, 37, 122, 14, 124, 65, 67
　　
　　 (74) Whant operation on relations R and S produces the relation shown below?
　　 {tuple│tuple∈R۸tuple∈\ S}
　　 A) Union B) Difference C) Intersection D) Division
　　
　　 (75) When embedding SQL in a C language program, the prefix that should be added to all SQL statements in order to distinguish SQL statements from the host language statements is
　　 A) ： B) EXEC C) EXEC SQL D) SQL
　　
　　 (76) In the ORACLE system,sets of SQL statements and control flow statements that have been named,compiled,and stored tn the database are referred to as stored
　　 A) batches B) procedures C) triggers D) transactions
　　
　　 (77) Which of the following statements about object oriented databases is NOT correct? (2分)
　　 A) Each object has a unique object identity in the system.
　　 B) Encapsulation and inheritance are two important features of object oriented databases.
　　 C) A subclass can inherit the attributes and methods of all its superclasses.
　　 D) A superclass includes the attributes and methods of all its subclasses.
　　
　　 (78) In the design phase of software engineering, decomposition of the program into modules should follow the principles of
　　 A) low cohesion with low corpling B) low cohesion with high coupling
　　 C) high cohesion with low coupling D) high cohesion with high coupling </P><P>　　
　　 (79) Specifications for software should contain&nbs p;several components, e.g., specifications of
　　 information flow,
　　 user interface,
　　 functional requirements, and
　　 design constraints.
　　 Two other important components are specifications of the (2分)
　　 A) methods of testing and ways to obtain quality assurance
　　 B) criteria for testing and ways to obtain quality assurance
　　 C) methods of testing and criteria for function assurane
　　 D) criteria for testing and methods of function assurance</P><P></P><P>　　(80) Which of the following statements about testing software with data is (are) true?
　　 I. The primary purpose of such testing is to find errors.
　　 II. Such testing can demonstrate the existence of errors but cannot
　　 demonstrate the absence of errors.
　　 A) Neither B) Ⅰ only C) Ⅱ only D) Ⅰ and Ⅱ
　　
　　 (81) The type of testing done during software implementation and beforemodule integration is called
　　 A) unit testing B) beta testing
　　 C) system testing D) acceptance testing
　　
　　 (82) Which of the following is (are) true about software portability?
　　 I. Using a high-level language that conforms to an ISO standardguarantees portability across the range of machines that support the language.
　　 II. Portability is guaranteed across all machines that have the same instruction set and operating system. (2分)
　　 A) Neither B) Ⅰ only C) Ⅱ only D) Ⅰ and Ⅱ
　　
　　 (83) A memory-memory, machine instruction for a certain machine has the following format.
　　 (Such an instruction is similar to a register-register instruction
　　 except that the operands are displaced addresses in memory.)
　　 opcode meml displ1 mem2 displ2
　　 Which of the following could be an assembly lanuage instruction that would be translated into a memory-to-memory instruction for this machine?
　　 A) ADD 10(R1), 20(R2) B) ADD(10R1), (20R2)
　　 C) ADD R1, 10(R2), 20 D) ADD R1, 10, 20(R2)
　　
　　 (84) In a certain cache system, the modified cache block is written to main memory only when the block is replaced. All of the following are used to describe this policy EXCEPT
　　 A) store-in B) write-back C) copy-back D) write-through
　　
　　 (85) When an amount of memory is requested that is less than the size of a page, but a full page is allocated, the r esulting waste of memory is called
　　 A) external fragmentation B) internal fragmentation
　　 C) inaccessible page faults D) inaccessible garbage
　　
　　 (86) The time that the CPU spends on a given program can be computed using all of the following expressions EXCEPT (2分)
　　 A) (CPU clock cycles for the program)*(clock cycle time)
　　
　　 B) CPU clock cycles for the program
　　 clock rate
　　
　　 C) (Instruction count)*CPI
　　 clock rate
　　
　　 D) (CPU clock cycles for the program)*CPI
　　 clock rate
　　
　　 (87) The methods used in Asynchronous Transfer Mode (ATM) are switch technology and which of the following is used to describe this mode?
　　 A) cell exchange B) packet exchange
　　 C) message exchange D) information exchange
　　
　　 (88) In a data communication system, the transport media with the widest frequency band and best reliability is the
　　 A) telephone line B) coaxial cable
　　 C) radio channel D) fiber optic cable
　　
　　 (89) Which of the following statements about the Internet is (are) true?
　　 I. It is possible to have multiple names corresponding to the same IP address. II. All host names must be registered with an Internet-wide central registry.
　　 A) Neither B) Ⅰ only C) Ⅱ only D) Ⅰ and Ⅱ
　　
　　 (90) According to the principle of CRC calculation, given a frame-bit series M =11100111 and the multiple-term formula, frame-bit series generated by the CRC G =110011, then the CRC is (2分)
　　 A) 111101 B) 00011 C) 11010011 D) 1101001

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