Quiznetik

Operating System Architecture | Set 3

1. The first set of the three permissions (rw) pertains to the owner of the file, indicating that the owner has

A. executable permission only

B. write and executable permissions

C. both read and executable permissions.

D. both read and write permissions

Correct : D. both read and write permissions

2. Which of the following commands is used to save the output of the who command in a file named user.lst, as well as display it?

A. who | tee user.lst

B. who > user.lst

C. who >> user.lst

D. who < user.lste

Correct : A. who | tee user.lst

3. Which of the following shell's wildcards are used to match any number of characters including none?

A. [ijk]

B. [!ijk]

C. ?

D. *

Correct : D. *

4. Which symbol will be used with grep command to match the pattern pat at the end of a line?

A. ^pat

B. $pat

C. pat$

D. pat^

Correct : C. pat$

5. Which command is used to display all the lines with the string 'sales' from the file empl.lst?

A. cut sales empl.lst

B. /sales > empl.lst

C. grep sales empl.lst

D. cat | /sales > empl.lst

Correct : C. grep sales empl.lst

6. Which of the following commands is note the vi Input mode command?

A. rch

B. r

C. s

D. j

Correct : D. j

7. Which of the following commands is used to remove files?

A. erase

B. delete

C. rm

D. dm

Correct : C. rm

8. Which command is used with vi editor to save file and remain in the editing mode?

A. :q

B. :w

C. q!

D. :x

Correct : B. :w

9. Which of the following commands is used to have a two-way communication with any person who is currently logged in?

A. mail

B. mesg

C. write

D. grep

Correct : C. write

10. Which command is used with vi editor to move the cursor to the left?

A. i

B. j

C. k

D. h

Correct : D. h

11. Which command is used to terminate all processes in your own system except the login shell?

A. kill 1

B. kill 0

C. cancel all

D. cancel 1

Correct : B. kill 0

12. Which command is used to link the files?

A. ik

B. in

C. cp

D. tar

Correct : B. in

13. Which of the following signs is used to back up over typing errors in vi?

A. @

B. #

C. $

D. !

Correct : B. #

14. Which of are following internal commands is used in mail to forward mail to user in user-list?

A. r user-list

B. m user-list

C. d user-list

D. e user-list

Correct : B. m user-list

15. Which of the following commands is used to display the filenames in multiple columns?

A. ls

B. ls -1

C. ls -x

D. lc

Correct : C. ls -x

16. Which of the following features of UNIX may be used for inter process communication?

A. signals

B. pipes

C. semaphore

D. all of these

Correct : D. all of these

17. The command echo welcome > /dev / tty

A. echoes welcome in all the terminals that are switched on.

B. echoes welcome in all the terminals that are logged on.

C. echoes welcome only in the terminal in which it is run.

D. both (a) and ©

Correct : D. both (a) and ©

18. dev/null

A. is a file

B. has write permission for all

C. is the unix built- in dustbin

D. all of these

Correct : D. all of these

19. The permission bits of a file noname. can be set to _rws_ _x_ _x by the command.

A. chmod 711 noname

B. chmod go -rw noname

C. chmod 2711 noname

D. none of the above

Correct : D. none of the above

20. /bin/passwd has the user execution permission set to 's' because

A. this facility assigns to the user, permissions of the program owner. temporarily

B. it should allow users who don\t have write permission to /etc/passwd to write to it

C. /etc/passwd is write protected

D. all of these

Correct : D. all of these

21. If one doesn't want anyone else to read or write to a file named datfile, except through a program in a file filex , then he may use

A. chmod u+s filex ; chmod go_rw datfile

B. chmod 4711 filex ; chmod go_rw datfile

C. chmod 4711 datfile ; chmod go_rw filex

D. both (a) and (b)

Correct : D. both (a) and (b)

22. Writing a C program that accepts input from keyboard, rather than from a file is advantageous because

A. keyboard is a file that is already open

B. it can be used in a pipe, if it writes to stdout

C. both (a) and (b)

D. none of the above

Correct : C. both (a) and (b)

23. Consider the following command that invokes the executable file a.out, with the following command line arguments a .out God loves you argv( [1][2] )corresponds to the character

A. e

B. o

C. y

D. d

Correct : D. d

24. Which of the following string functions can be used to find the last occurrence of a given character in a given string?

A. strncmp

B. strncpy

C. strchr

D. none of the above

Correct : D. none of the above

25. Consider the program main ( ) { printf("He arose a victor from\n"); system ("date") ; printf("the dark domain"); } If a.out is the executable code corresponding to the above source code, then the command a.out > out f

A. redirects the output of date to file out f

B. displays the output of date on the screen

C. prints everything on the screen

D. prints the two messages on the screen

Correct : A. redirects the output of date to file out f

26. The default permission bits of a file when it is created for the first time, is controlled by

A. chmod value

B. fmask value

C. umask value

D. none of the above

Correct : C. umask value

27. Let x.c be a C source code. The command cc x.c > y

A. is equivalent to the command cc x.c;mv a.out y

B. is equivalent to the command cc -o y x.c

C. serves no purpose

D. none of the above

Correct : C. serves no purpose

28. A file x is created with the following contents echo today is: date If you type x.then

A. it echoes the message. followed by date.

B. it gives the desired output only if the execute permission of file x is set.

C. the desired output can be got by the command sh x. which works even if x has its execute permission not set.

D. both (b) and ©

Correct : D. both (b) and ©

29. Shell script is preferable to other forms of programming because it

A. makes programming task easier

B. enhances portability

C. occupies less space

D. all of these

Correct : D. all of these

30. Choose the incorrect statements.

A. shell scripts can accept arguments

B. shell scripts are interpreted

C. shell is a programming language

D. shell scripts are compiled

Correct : D. shell scripts are compiled

31. Files that store data in the same format as used in program are called

A. binary files

B. source file

C. text file

D. core

Correct : A. binary files

32. To allow only one user to work with a particular file at a particular time, one has to use

A. semaphore

B. critical region

C. locking

D. dedicated mode

Correct : C. locking

33. Which of the following remarks about realloc are true?

A. it allocates memory of required size that need not be contiguous

B. it may shift the existing block

C. it can work only with an existing block of memory

D. both (b) and ©

Correct : D. both (b) and ©

34. The differences between malloc( ) and calloc() are:

A. malloc is used for dynamic allocation of memory, while cal:1c can't be used for that purpose

B. malloc needs only one argument. while cal loc needs two.

C. unlike malloc, calloc allocates memory and initializes it to 0.

D. both (b) and ©

Correct : D. both (b) and ©

35. The file that stores an integer as a sequence of characters is a

A. text file

B. data file

C. binary file

D. core file

Correct : A. text file

36. If cat x. prints garbage. then x is probably a

A. data file

B. binary file

C. text file

D. source file

Correct : B. binary file

37. Which of the following file names can be found in more than one directoy?

A. passwd

B. bin

C. date

D. both (a) and (b)

Correct : D. both (a) and (b)

38. /bin

A. is a bucket for storing information

B. has files in binary code

C. is a directory

D. both (b) and ©

Correct : D. both (b) and ©

39. The main reasons for the success of pipes are

A. the availability of many filter programs

B. unix treats devices as files

C. it provides a 2- way communication channel

D. both (a) and (b)

Correct : D. both (a) and (b)

40. Which of the following are not filter programs?

A. date

B. sort

C. cat

D. grep

Correct : A. date

41. Redirection in pipes can be achieved by using

A. >

B. >>

C. tee

D. lpr

Correct : C. tee

42. Choose the correct statements.

A. the symbols > and | are both processed by shell

B. > can be used to direct output to a named file

C. | can be used to direct output to programs

D. all of above

Correct : D. all of above

43. The command who sort - file1 > file2

A. results in an error

B. sorts the contents of file1 and puts it in file2

C. both (a) and (b)

D. none of the above

Correct : D. none of the above

44. The system identifies a file by its

A. name

B. absolute path

C. both (a) and (b)

D. mode number

Correct : D. mode number

45. The system identifies the end of a file by the

A. eof character

B. file size

C. i-node number

D. both (a) and (b)

Correct : B. file size

46. The command line argument a.out x 'a b' "c d"

A. is acceptable

B. is acceptable if the double quotes are replaced by single quotes

C. is acceptable if the single quotes arc replaced by double quotes

D. none of the above

Correct : A. is acceptable

47. Which of the following metacharacters will be recognized by the shell. even if it comes within double quotes?

A. $

B. *

C. ?

D. none of these

Correct : A. $

48. lint should be used

A. before compilation

B. to analyze a c code

C. after compilation

D. both (a) and (b)

Correct : D. both (a) and (b)

49. Environment variables can be accessed by

A. system programs

B. c programs

C. shell scripts

D. all of these

Correct : D. all of these

50. Which of the following are character special files

A. terminal

B. printer

C. modem

D. all of these

Correct : D. all of these

51. If one exports a variable

A. variables placed in the environment by a child process are not inherited by the parent process

B. it is passed to all its descendant processes

C. it dies when the shell that created it dies

D. all of these

Correct : D. all of these

52. Profilers are

A. tools that analyze the run time behaviour of a program

B. tools that check a c code for cross file consistency

C. tools that keep track of evolving versions of a file

D. none of the above

Correct : A. tools that analyze the run time behaviour of a program

53. The shell command :

A. does nothing

B. can be used to cause infinite looping

C. can take arguments but it cannot act on them

D. all of these

Correct : D. all of these

54. Which of the following tools can be used to keep track of evolving versions of a file

A. make

B. yacc

C. sccs

D. dv

Correct : C. sccs

55. The .(dot) shell command

A. can take command line argument

B. will fork a child shell to execute the named shell script

C. can be used to change the environment of the current shell

D. all of the above

Correct : C. can be used to change the environment of the current shell

56. m4

A. is a macro processor

B. can he used to preprocess c code

C. can be used to preprocess assembly language program

D. none of the above

Correct : C. can be used to preprocess assembly language program

57. If 7 terminals are currently logged on. then the command date ; who | wc -l, displays

A. date followed by 7

B. date followed by 8

C. date followed by 1

D. an error message

Correct : A. date followed by 7

58. Choose the correct answers if the command ls -l /dev/mt0 display's brw_rw_ _ _ _ 1 root 3, 0 Apr18 1:05 mt0

A. the \b\ indicates that it is a special file

B. mt0 indicates that it is a tape drive

C. the \ b\ indicates that data transfer is done in blocks

D. all of these

Correct : D. all of these

59. cat/dev/tty

A. throws garbage onto the terminal 1

B. just echoes what you type. line by line

C. terminates if one types control at the beginning of a line

D. both (b) & ©

Correct : D. both (b) & ©

60. The header files used in C programs arc usually found in

A. /bin/include

B. usr/bin/include

C. /dev/ include

D. iusr/include

Correct : D. iusr/include

61. A C program should be compiled with -g option (like cc -g x . c) to use

A. proof

B. make

C. lprof

D. sdb

Correct : D. sdb

62. The difference between a pipe and a regular file is that

A. unlike a regular file, pipe is not a file.

B. the data in a pipe is transient. unlike the contents of a regular file

C. pipes forbid random accessing. while regular files do allow this

D. both (b) and ©

Correct : D. both (b) and ©

63. Context switch changes the process mode from………

A. user to kernel mode

B. kernel to user mode

C. kernel mode to the kernel process

D. both (a) and (b)

Correct : D. both (a) and (b)

64. cc command sequentially invokes

A. preprocessor. compiler and link editor

B. compiler and link editor

C. preprocessor, compiler. assembler and link editor

D. compiler, assembler and link editor

Correct : C. preprocessor, compiler. assembler and link editor

65. The cc command

A. can take more than one argument

B. can act on files with . or . o extension

C. creates . o files by default when more than one argument with .,- extension is present

D. if provided with more than one argument. immediately terminates it the first argument fails to compile successfully

Correct : C. creates . o files by default when more than one argument with .,- extension is present

66. The mv command changes

A. only the directory entry

B. only the directory entry and i-node

C. only the i-node number

D. none of the above

Correct : A. only the directory entry

67. Which of the following programs are not interactive?

A. passwd

B. date

C. grep

D. both (b) & ©

Correct : A. passwd

68. Choose the correct statements.

A. any process has an associated owner id and group id

B. effective id defines who you are for the duration of a process

C. real id defines who you are for the duration of a process

D. both (a) & (b)

Correct : D. both (a) & (b)

69. No shell script can take input from

A. stdin

B. the output of the previously executed command redirected to it

C. the shell holds the script

D. none of the above

Correct : D. none of the above

70. The disadvantage of a pipe is that

A. it is a one way communication channel

B. it dies along with the process that created it

C. it can\t he shared by unrelated processes

D. all of these

Correct : D. all of these

71. The state of signals are

A. preserved across a fork call

B. not preserved across an exec call

C. preserved across an exec call

D. both (a) & (b)

Correct : D. both (a) & (b)

72. Which of the following displays the exit status of the last executed command?

A. echo $4

B. echo $$

C. echo $?

D. echo $!

Correct : C. echo $?

73. Which of the following file names cannot be displayed if la ls* is run?

A. .x

B. ?x

C. both (a) & (b)

D. hidden

Correct : C. both (a) & (b)

74. Which of the following initiates the sequence of events that ultimately allows a user to login?

A. clri

B. sync

C. login

D. init

Correct : D. init

75. What is ‘ps’ command for?

A. prints the status

B. prints the process status

C. prints the execution status

D. none

Correct : B. prints the process status

76. Which command is used to terminate the process?

A. wait

B. sleep

C. kill

D. none

Correct : C. kill

77. Which commaand is use for the copy in unix?

A. copy

B. cp

C. cpy

D. none

Correct : B. cp

78. What is stand for IPC?

A. inter procedure communication

B. inter process communication

C. inter part compare

D. none

Correct : B. inter process communication

79. Which one is best in action between fork() and vfork()?

A. fork()

B. vfork()

C. both

D. none

Correct : B. vfork()

80. fork system call…..

A. control the size of memory allocated to a process

B. create a new process

C. overlay image of a program onto the running process

D. finish executing a process

Correct : B. create a new process

81. exec system call……..

A. create a new process

B. finish executing a process

C. control the size of memory allocated to a process

D. overlay image of a program onto the running process

Correct : D. overlay image of a program onto the running process

82. wait system call…………

A. finish executing a process

B. control the size of memory allocated to a process

C. synchronize process execution with exit of previously forked process

D. overlay image of a program onto the running process

Correct : C. synchronize process execution with exit of previously forked process

83. brk system call…………

A. synchronize process execution with exit of previously forked process

B. control the size of memory allocated to a process

C. finish executing a process

D. overlay image of a program onto the running process

Correct : B. control the size of memory allocated to a process

84. signal system call…………

A. control process response to extraordinary events

B. control the size of memory allocated to a process

C. synchronize process execution with exit of previously forked process

D. overlay image of a program onto the running process

Correct : A. control process response to extraordinary events

85. Two policies for managing memory are……………

A. swaping and demand paging

B. semaphore and deadlock

C. scheduling and wait

D. none

Correct : A. swaping and demand paging

86. Schedular module allocate …..

A. processes to cpu

B. cpu to processes

C. processes to kernel

D. none

Correct : B. cpu to processes

87. The file subsystem accesses file data using a buffering mechanism that regulates ….

A. data flow between the kernel and secondary storage devices.

B. data flow between secondary storage devices to kernel

C. data flow of kernel

D. none

Correct : A. data flow between the kernel and secondary storage devices.

88. The internal representation of a file is given by ……..

A. an inode

B. semaphore

C. pipes

D. none

Correct : A. an inode

89. Every file in unix has …..

A. two inode

B. one inode

C. no inode

D. none

Correct : B. one inode

90. inode name is also called……

A. file

B. link

C. file

D. file descriptors

Correct : B. link

91. When a process creates a new file, the kernel assigns it an ……...

A. used inode

B. unused inode

C. integer number

D. file number

Correct : B. unused inode

92. With inode, the kernel contains two data structures………….

A. file table and user file descriptor table

B. file system and kernel

C. file and semaphore

D. none

Correct : A. file table and user file descriptor table

93. Which of the following is not A system calls?

A. chmod

B. open

C. lseek

D. getc

Correct : D. getc

94. Mounting a file system results in the loading of

A. boot block

B. super block

C. i-node table

D. all of these

Correct : B. super block

95. If cat x ,prints garbage ,then x is probably a

A. data file

B. binary file

C. text file

D. source file

Correct : B. binary file

96. An attempt to read from locked file,results in

A. prematured termination

B. a deadlock

C. an indefinite wait

D. none of the above

Correct : D. none of the above

97. To allow only one user to work with a particular file at a particular time ,one has to …..

A. semaphore

B. critical region

C. locking

D. dedicated mode

Correct : C. locking

98. Which of the following are character special files?

A. terminal

B. printer

C. modem

D. tape drive

Correct : C. modem

99. Which of the following sections of an executable binary file has all uninitialized data items?

A. bss

B. data

C. header

D. symbol

Correct : A. bss

100. Which of the following files contains information related to password aging?

A. shadow

B. profile

C. password

D. all of these

Correct : C. password