计算机等级考试四级笔试试卷及答案五之三（3）

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　　69) Which UNIX command creates a symbolic link named myfile in the current directory to
　　the file/etc/hosts?
$ B1 y# A8 G# R4 [0 C　　A) In -s /etc/hosts myfile B) In -s myfile /etc/hosts
8 Y! z3 R& q& Z0 X; @. D; m　　C) link -s /etc/hosts myfile D) link -s myfile /etc/hosts
9 I) x3 r& }1 \* g. a　　(70)Which MS-DOS command is correct?
　　A) DEL /s *.bat B) DEL *.exe/sp
$ y) t7 X% g  y. v$ y/ }　　C) DEL *.obj >nul: D) DEL *.com *.sys
　　(71)A virtual memory system has five virtual pages numbered zero through four and
　　three page frames. All the page frames are initially empty. How many page faults
　　are generated with the following access sequence using a FIFO replacement policy?
+ S  n# d; j* y6 p7 D　　(2 Points)
- F# Y0 n# i% b　　0 1 2 3 0 1 5 0 1 2 3 4
8 g  j# q+ \/ F# q　　A) 8 B) 9 C) 10 D) 11
8 p& w. I- V# ]0 `* {; K0 T　　(72)Which element is NOT part of a microkernel? (2 Points)
　　A) basic I/O B) a file system
6 j7 {: ?; A& ]- a* f/ E5 g　　C) IPC mechanisms D) memory management
. Z' W. j9 x) ~9 H) g: r3 H' G; C　　(73)Which is local to a thread instead of a process? (2 Points)
　　A) a stack B) an open file C) a semaphores D) an address space
1 s+ f  c, A; y& v- S1 z# m　　(74)What is a subselect statement?
  X) g+ F- S9 y! f7 l7 u; O! V　　A)a select statement that selects a subset of fields in a table
# t. L! g1 P: G6 R; A% f9 A　　B)a select statement that re
; l0 n! G% a9 p% E! J9 q! k7 R' \5 K& Z3 @　　turns a subset of the data in a table
  P! N4 @0 g& F: H5 y* P3 I　　C)a select statement that appears within another select statement
6 }- L" `* ^2 B1 s7 q( Q4 a2 h　　D)a select statement that returns a subset of the constraints on a field
8 a' c9 D* v" [* a6 w# ^$ g* g" K0 N' ~　　(75)In developing a hospital database,it is determined that on the average,each patient
+ g" H6 F) K/ T. \" M. f　　will have 6 treatments during a hospital stay. The averge length of a stay is three
　　days.The hospital has 1000 beds.There are on the average 800 patients occupying
# Y& z* s& M! ~　　beds each day.The relationship between PATIENT and TREATMENT is l:M.The relationship
" [& E$ Z/ x% \$ P　　between PATIENT and BED is 1: 1,conditional. If treatment record occurrences are
　　archived as soon as a patient is discharded from the hospital, how many occurrences
　　of the TREATMENT records will be stored in the TREATMENT database file on the
, c! l5 X$ H1 L2 g- {. w! y2 P　　average? (2 Points)
　　A) 6,000 B) 4,800 C) 18,000 D)1,600
　　(76)Which of the following conditions will make a relation that is in first normal form
! X8 m1 J' _2 I6 ?% M) t　　to be in second normal form?
" A. c$ |* T0 B1 Z8 D　　Ⅰ.every non-key attribute is functionally dependent on the full set of primary key
  b$ h! \( I) E6 e3 q' _　　attributes.
+ b/ l3 }, s. ?  c5 s% c! T2 j　　Ⅱ.no non-key attributes exist in the relation.
　　Ⅲ.the primary key consists of only one attribute.
$ m5 C* f- Y1 Y+ N$ O/ k" @　　A) Ⅰ only B) Ⅰand Ⅱ only C) Ⅰand Ⅲ only D) any of them
　　(77)The most commonly used locking level in implementing concurrency control is at which
, M0 E4 p/ J  ?　　of the following levels?
4 g; P) S$ K* H　　A) database B) table C) record D)field
　　(78)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
: Y; J7 v, H% u  Z! z　　C) It assists in estimating the cost of the project.
　　D) It is used as the foundation of the larger projects.
　　(79)Software document is an important part of software and a basis of software development
　　phase.It also influnces software’s (2 Points)
! C$ I0 C" B& d' y* p8 }; S2 r　　A) Reusability B) Maintanence
8 D5 `. c6 K& d5 S　　C) Expansibility D) Portability
) d2 M; h5 @$ y　　(80) Which phase of the software development requires the most development time?
* O% p' C" `( _4 {- Y　　A) the design phase B) the testing phase
　　C) the maintenance phase D) the development phase