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（61）the basic function of the file system is accessing files by names. the function can be realized by
a）directory-managing b）boosting the speed of the file-accessing
c）file-protecting d）improving the utilization of storage
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（62）which one of the following statements is wrong regarding software testing?
a）when 100% statement coverage is achieved, 100% branch coverage is obtained
b）decision coverage means branch coverage
c）condition coverage is more complex than decision coverage
d）white box testing is not stricter than black box testing
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（63）in the iso 9126, there are six key software quality properties, including functionality, reliability, usability, efficiency, maintainability, as well as
a）correctness b）security c）portability d）stability
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（64）which one of the following expressions is equivalent to ‘x between 15 and 25’ ?
a）x>15 and x<25 b）x=15 and x=25 c）x>25 and x<15 d）x>=15 and x<=25
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（65）let the schema r(u, f), u=abcd, f={a→bc, c→d }. the schema r(u, f) is in the normal form of
a）1nf b）2nf c）3nf d）bcnf
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（66）the data hazard in pipeline does not include
a）raw b）waw c）war d）rar
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（67）the information can be written into both the block in the cache and the block in the memory. this kind of technique used in the cache is called
a）write through b）copy back c）write buffer d）copy through
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（68）the operation of the internet is closely monitored by the routers. when something unexpected occurs, the event will be reported by the protocol
a）igmp b）icmp c）ip d）ospf
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（69）when a large packet wants to travel through a network whose mtu is too small, one solution is to allow routers to break up the packet into
a）messages b）frames c）fragments d）bits
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（70）what refers to the protocols used to determine who goes next on a multi-access channel?
a）mac (medium access control) b）arp (address resolution protocol )
c）nat (network address translation) d）cidr (classless interdomain routing)