(61) The construct
cobegin
Statement1;
Statement2;
coend
means Statement1 and Statement2 are to be executed in parallel. The only two atomic actions in this construct are loading the value of a variable and storing into a variable. For the program segment
x:=0；
y:=O；
cobegin
begin
x:=l;
y:=y+x;
end;
begin
y:=2;
x:=x+3;
end
coend
Which of the following indicate(s) possible values for the variables when the segment finishes execution?
Ⅰ．x=1,y=2
Ⅱ．x=1,y=3
Ⅲ．x=4,y=6
A．Ⅰ
B．Ⅰ and Ⅱ C)Ⅰ and Ⅲ
D．Ⅱ and Ⅲ
(62) Software maintenance is to do necessary modification,supplenemt, and completeness during software life circle. Among the following vary kinds of maintenance,which one has the maximum workload in a general way?
A．relevance maintenance
B．completeness maintenance
C．correctness naintenance
D．other kinds of maintenance
(63) Different quality factors of software can be reflected upon user’s different points of view,through product running,product modification and product transformation. Of the following properties,which one is connected with product running?
Ⅰ．correctness Ⅱ．robustness Ⅲ．re-use
A．Ⅰonly
B．Ⅱonly
C．Ⅰ+Ⅱ
D．all of above
(64) Let R and S be the relation respectively:
Relation R: A B C Relation S: B C D
1 2 3 2 3 4
6 7 8 2 3 5
9 7 8 7 8 1
The number of tuples that the result of the expression R ∞ S (Here is the natural join of relations R and S) is
A．3
B．4
C．6
D．9
(65) Suppose we have the relation schema R(A,B,C,
D．with functional dependencies;F{A→B,B→C,C→D,D→A},then R(A,B,C,D)at least is in
A．1NF
B．2NF
C．3NF
D．BCNF
(66) By means of multiple pipeline to carry out multiple processing,this technologyiscalled
A．Multiple pipeling
B．Superpipeline
C．Superscalar
D．Very long instruction word
(67) There are many page replacement algorithms in the page management. Most frequently used algorithm is
A．FIFO
B．PPT
C．OPT
D．LRU
(68) Layer n on one machine carries on a conversation with layer n on another machine. The rules and conventions used in this conversation are collectively known as the layer n
A．topology
B．protocol
C．service
D．peer
(69) Transport gateways connect byte streams in the transport layer. Application gateways allow interworking above
A．network layer
B．data link layer
C．transport layer
D．application layer
(70) Every host and router on the Internet has an IP address, which encodes its
A．host number
B．host number and socket
C．network number
D．host number and network number
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