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(57) 假设一种简单的情况：一台在Internet上的主机要向另一台遵循OSI 协议标准的主机发送IP分组。OSI数据报协议(CLNP)是基于IP协议的。问题是IP 分组的报头带有一个32位的目的主机的Internet地址。OSI主机不能直接处理32 位的Internet地址。为了使两台主机能够通信，我们应该选择的网络互连设备是
A) repeater B) bridge C) multiprotocol router D) switch
(58) 802.3协议的每个版本都规定了每个缆段的最大电缆长度,为了增加电缆长度。可以通过repeater将多个缆段连接起来，对于软件来说，由repeater连接的多个缆段
A) 与单个缆段没什么不同 B) 与单个缆段是不同的
C) 构成了多个Ethernet网 D) 构成了一个互连的LAN
(59) 大多数局域网在数据链路层提供的是
A) 面向连接确认服务 B) 无连接不确认服务
C) 面向连接不确认服务 D) 网络服务
(60) TCP/IP 模型的传输层有两个协议，第一个协议TCP是一种可靠的面向连接的协议，第二个协议UDP(User Datagram Protocol)是
A) 一种可靠的面向连接的协议 B) 一种不可靠的面向连接的协议
C) 一种可靠的无连接协议 D) 一种不可靠的无连接协议
(61) There are several periods in a computer，the shortest period is
A) Instruction period B) Machine period C) Beat period D) CPU period
(62) Which set is empty?
A)｛x|x is a real number and x2=9 B)｛x|x is a real number and x2-1=0｝
C)｛x|x is a real number and x2+1=0｝ D)｛x|x is a real number and x=2x+1｝
(63) What is the relation represented in the exhibit shown below?
A) R={(1,2),(1,3),(1,4),(1,5)}
B) R={(1,1),(2,2),(3,3),(4,4),(5,5)}
C) R={(1,2),(1,3),(1,4),(2,3),(4,1),(4,5),(5,5)}
D) R={(1,2),(1,3),(1,4),(2,2),(2,3),(4,1),(4,4),(4,5)}
(64) What is the contrapositive of the following implication?“If it is raining，then I get wet.”
A) If I get wet，then it is raining.
B) If I am wet ，then if is raining.
C) If it is not raining, I do not get wet.
D) If I do not get wet，then it is not raining.
(65) Which property does R posses? (2 grades)
Let A={1,2,3,4} and let R ={<1,2>,<2,2>,<3,4>,<4,1>}
A) Symmetry B) Reflexivity C) Asymmetry D) Antisymmetry
(66) When walking a tree, which traversal method yields a prefix, or Polish,form?
A) lnorder B) Preorder C) Postorder D) Reorder
(67) ln the following statements about graph operations, which one is NOT correct?
(2 grades)
A) Spanning tree of a graph may not be unique.
B) Minimum spanning tree of a graph may not be unique.
C) Finding critical path is an operation on directed graph.
D) Finding critical path is an operation on undirected graph.
(68) Which traversal method for a binary tree does the following Pascal code illustrate? (2 grades)
procedure traverse(p:pointer);
begin
if p<>nil
then begin
traverse(p↑.left);
process(p);
traverse(p↑.right)
end
end;
A) lnorder B) Preorder C) Postorder D) Reorder
(69) What storage scheme does MS-DOS use for storing files on a disk?
A) I-nodes B) a linked list allocation
C) a continuous allocation D) a linked list with index
(70) Which of the followings is NOT a condition for deadlock?
A) Starvation B) Circular Wait
C) No Preemption D) Mutual Exclusion
(71) Assume that an operating system uses a round-robin scheduler. The process’s quantum is 20 msec,and the context switch is 5 msec. What percentage of the CPU’s time is spent on administrative overhead? (2 grades)
A) 5％ B) 15％ C) 20％ D) 25％
(72) What state is a process in when it can’t run because it needs a resource to become available? (2 grades)
A) Ready B) Interrupt C) Blocked D) Running
(73) The following sectors are requested from the disk:
11,1,36,16,34,9,12
What is the order of the sector reads if you are using the elevator algorithm?
(2 grades)
A) 1,9,11,12,16,34,36 B) 11,1,36,16,34,9,12
C) 11,12,9,16,1,34,36 D) 11,12,16,34,36,9,1
(74) What is the candidate key of a relational database?
A) A field with a constraint placed on it.
B) A set of fields that have no data in them.
C) A set of fields in a table used to identify a record uniquely.
D) Fields from multiple tables that are used for sorting records.
(75) What Normal From is the table shown in the exhibit? (2 grades)
emps tbl
emp_idemp_nameemp_phonedept_namedept_phonedept_mgrname
(1) emp_id→emp_name, emp_phone, dept_name(2) dept_name→dept_phone, dept_mgrname
A) 1NF B) 2NF C) 3NF D) BCNF
(76) Which operating system can Oracle database NOT be used in?
A) DOS B) UNIX C) Windows95 D) IBM Mainframes
(77) Which values are NOT permitted to be part of the prima
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