計(jì)算機(jī)等級考試四級考試模擬試題(4)
(49) 目前計(jì)算機(jī)網(wǎng)絡(luò)的通信子網(wǎng)中所采用的傳輸技術(shù)可以有兩類，即點(diǎn)一點(diǎn)方式與( )。
A) 模擬方式 B) 廣播方式 C) 數(shù)字方式 D) 軟件方式 ;
(50) 當(dāng)PCM 用于數(shù)字化語音系統(tǒng)時(shí)，它將聲音分為128 個(gè)量化級， 若采樣速率為7000 樣
本/秒，則數(shù)據(jù)傳輸速率應(yīng)該達(dá)到( )。
A) 2880bps B) 56Kbps C) 49Kbps D) 1200bps
(51) OSI模型的三個(gè)主要概念是( )。
A) 服務(wù)、接口、層 B) 接口、層、應(yīng)用
C) 服務(wù)、接口、協(xié)議 D) 網(wǎng)絡(luò)、應(yīng)用、協(xié)議
(52) 隨著光纖技術(shù)、多媒體技術(shù)、高分辨率動(dòng)態(tài)圖像與文件傳輸技術(shù)的發(fā)展，CCITT 提出
將語音、數(shù)據(jù)、靜態(tài)與動(dòng)態(tài)圖像等所有服務(wù)綜合于一個(gè)網(wǎng)中傳輸?shù)耐ㄐ啪W(wǎng)，這種通信
網(wǎng)絡(luò)就是( )。
A) B-ISDN B) N-ISDN C) MAN D) LAN
(53) 具有分時(shí)系統(tǒng)文件管理的全部功能，提供網(wǎng)絡(luò)用戶訪問文件、目錄的并發(fā)控制與安全
保密功能的局域網(wǎng)服務(wù)器叫做( )。
A) BBS 服務(wù)器 B) WWW 服務(wù)器
C) FS 服務(wù)器 D) TELENT 服務(wù)器
(54) 在網(wǎng)絡(luò)層實(shí)現(xiàn)多個(gè)局域網(wǎng)互連的設(shè)備是( )。
A) 中繼器 B) 網(wǎng)橋 C) 網(wǎng)關(guān) D) 路由器
(55) 異步傳輸模式ATM 中的每個(gè)信元的長度是( )。
A) 37 字節(jié) B) 39 字節(jié) C) 41 字節(jié) D) 43 字節(jié)
(56) Give the logical variables X=0，Y=1, The value of X∧Y(logical multiply) is
( )。
A) 1 B) 2 C) 10 D) 0
(57) The Instruction Register (IR) is normally used to point out( )。
A) The address of next execution instruction
B) The address of last execution instruction
C) The current execution instruction
D) None of above
(58) When the adjacency matrix method is used to store a graph, which of the
statements is (are) true? ( )。
A) None B)I only C)II only D)I and II
Questions 59-60are based on the following information,
A hash table with hash function
H1 (k)=k mod 13
Is shown below.
0 1 2 3 4 5 6 7 8 9 10 11 12
35
33
48
25
Collision is rsolved using the hash function H2 (k)=(k mod 11)+1
(59)How many key comparisons occur in searching for key 35 in the given hash table?
( )。
A)0 B)1 C)2 D)3
(60)If a new key 67 is inserted into the given hash table, what will be its address?
( )。
A)3 B)4 C)5 D)6
(61)What is the contrapositive of the relation represented in the exhibit shown
below? ( )。
4
2
1
35
A) R={<1,2>,<1,3>,<1,4>,<1,5>}
B) R={<1,1>,<2,2>,<3,3>,<4,4>,<5,5>}
C) R={<2,1>,<4,1>,<2,2>,<1,3>,<3,2>,<1,4>,<4,4>,<5,4>}
D) R={<1,2>;,<3,1}>,<1,4>,<2,2>,<2,3>,<4,1>,<4,4>,<4,5>}
(62)Which function is NOT served by building a prototype? ( )。
A) It takes the place of the final system.
B) It assists in gathering software requirements.
C) It assists in estimating the cost of the project.
D) It is used as the foundation of the larger projects.
(63)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
(64)Inthefollowing statements about functional dependency, whichone isincorrect?
( )。
A) If X'X, then X→X'.
B) If X→Y and Y'Y, then X→Y'.
C) If X→Y and X'X, then X'→Y.
D) If X→Y and Y→Z, then X→Z.