2. Computer Science Engineering (CSE)
  3. Operating System Architecture
  4. Set 1

Operating System Architecture Solved MCQs

Take a Test
1.

What is an internal command in Unix ?

A. commands that are executed directly by the kernel
B. commands that are executred directly by the shell
C. commands that are executed directly by shell and kernel
D. commands will have a process id running for it
Answer» B. commands that are executred directly by the shell
discuss
2.

What is major device number ?

A. it is an index to the kernel table that contains the address of all device driver functions known to the system
B. it is an index to theuser process table that contains the address of all device driver functions known to the system
C. it is an index to the kernel table that contains the address of all files
D. it is an index to the kernel table that contains the address of all directories
Answer» A. it is an index to the kernel table that contains the address of all device driver functions known to the system
discuss
3.

The game program,"space travel"for GECOS system was written in

A. basic
B. cobol
C. fortran
D. vb
Answer» C. fortran
discuss
4.

What does OSS stand for

A. open system software
B. original source software
C. open source software
D. original system server
Answer» C. open source software
discuss
5.

Which of the following is used to write disk block images from memory to disk

A. stty
B. cmd
C. sync
D. clri
Answer» C. sync
discuss
6.

How many line are there are in the result of date command

A. three
B. one
C. two
D. five
Answer» B. one
discuss
7.

While providing a text processing system for the patent department at bell labs,the unix system was moved to in 1971

A. pdp-6
B. pdp-7
C. pdp-9
D. pdp-11
Answer» D. pdp-11
discuss
8.

What is minor device number           

A. it tells the device driver function what actual physical device it is talking
B. it tells the device driver functionwhat actual physiacl device it is talking to and i/0 buffernig scheme to be used for reading
C. it tells the device driver functionwhat actual physical device it is talking to and i/0 buffernig scheme to be used for writing
D. it tells the device driver functionwhat actual physiacl device it is talking to and i/0 buffernig scheme to be used for data transfer
Answer» D. it tells the device driver functionwhat actual physiacl device it is talking to and i/0 buffernig scheme to be used for data transfer
discuss
9.

What is directory hierarchy ?

A. it is an organizational structure in which directories can contain files and other sub directories
B. it is an organizational structure in which directories can contain only files
C. it is an organizational structure in which directories can contain only sub directories
D. it is an organizational structure in which directory contains only one level
Answer» A. it is an organizational structure in which directories can contain files and other sub directories
discuss
10.

what is the relationship of a filename to its inode

A. one to one
B. one to many
C. many to one
D. many to many
Answer» C. many to one
discuss
11.

Unix os was first rewritten in C in

A. 1971
B. 1972
C. 1973
D. 1974
Answer» C. 1973
discuss
12.

Among the directory entries inode and file contents which will be changed when a file is updated

A. only inode
B. only inode and file contents
C. only directory entry and file contents
D. none of the above
Answer» B. only inode and file contents
discuss
13.

what is the use of exec command

A. command that can be used to write files in shell scripts
B. command that can be used to read files in shell scripts
C. command that can be used to open files in shell scripts
D. all of the above
Answer» C. command that can be used to open files in shell scripts
discuss
14.

Which of the following sections of an executable binary file has all un initialized data items

A. bss
B. data
C. header
D. symbol table
Answer» A. bss
discuss
15.

The previous system administartor has put useless messages at login . What file do you edit to change the system message

A. /etc/motd
B. /etc/str
C. /etc/strtms
D. /etc/.conf
Answer» A. /etc/motd
discuss
16.

Suppose that a process is in BLOCKED state waiting for some i/o service. When a service is completed, it goes to the

A. running state
B. ready state
C. suspended state
D. terminated state
Answer» B. ready state
discuss
17.

Buffering mechanisms regulated the data between

A. secondary storage device and memory
B. system call interface and device driver
C. kernel and secondary storage device
D. buffer cache and file system
Answer» D. buffer cache and file system
discuss
18.

A thread is a ---- process

A. light weight
B. interface
C. heavy weight
D. inter thread
Answer» A. light weight
discuss
19.

A RAID system is useful because --

A. it increases interface performance
B. it increases speed of the processor
C. increases disk storage capacity
D. increase processor speed
Answer» C. increases disk storage capacity
discuss
20.

NFS stands for

A. normal file system
B. network file system
C. network format system
D. normal format system
Answer» B. network file system
view more info and meaning of NFS external link
discuss
21.

How many fields are there in /etc/passwd file

A. 3
B. 7
C. 10
D. 8
Answer» B. 7
discuss
22.

Thomson and Ritchie published a paper describing unix system in

A. ieee xsactions on computers
B. international jouranal of computer
C. communicatio-ns of the acm
D. internal " "os
Answer» C. communicatio-ns of the acm
discuss
23.

Command to reboot the system

A. shutdown -k now
B. shutdown -l now
C. shutdown -r now
D. shutdown -s now
Answer» C. shutdown -r now
discuss
24.

grep means

A. global regular expression print
B. global revearse expression print
C. global random expression print
D. global relative expression rpint
Answer» A. global regular expression print
discuss
25.

A history file

A. contains list of files used during a session
B. contains list of directories used during a session
C. contains list of directories and sub directories used during a session
D. contains list of commands used during a session
Answer» D. contains list of commands used during a session
discuss
26.

Programs like shell and editors (ed and vi) interact with the kernal by invoking

A. system calls
B. systems hardware
C. n/w program
D. interfacing hardware
Answer» A. system calls
discuss
27.

Internal or external command is checked using

A. ls
B. tty
C. etc
D. type
Answer» D. type
discuss
28.

The standard name for executable files produced by c compiler is

A. b.out
B. c.out
C. a.out
D. d.out
Answer» C. a.out
discuss
29.

       script is run for successful login

A. /etc/profile
B. /etc/str
C. /etc/strtms
D. /etc/.conf
Answer» A. /etc/profile
discuss
30.

The root node in the file system is write as

A. /
B. \\
C. /..
D. ../
Answer» A. /
discuss
31.

       interacts with inner part of kernel

A. interface
B. shell
C. terminal
D. compiler
Answer» B. shell
discuss
32.

       is used to stop a process

A. kill
B. remove
C. clear
D. overt
Answer» A. kill
discuss
33.

directory attributes are displayed by

A. ls-l-a
B. ls-l-b
C. ls-l-c
D. ls-l-d
Answer» D. ls-l-d
discuss
34.

The x in the cat x command is

A. binary file
B. data file
C. text file
D. source file
Answer» A. binary file
discuss
35.

what is the run level for shut down and reboot respectively

A. 0 and 6
B. 1 and 6
C. 0 and 4
D. 1 and 4
Answer» A. 0 and 6
discuss
36.

The text formatting program traff

A. expects to find new line character at the end of each line of text
B. expects to find last character at the end of each line of text
C. expects to find each line of text
D. expects to neglect each line of text
Answer» A. expects to find new line character at the end of each line of text
discuss
37.

The system acctcom accounting program

A. expects to find variable length records
B. expects to find fixed length record
C. expects to sort the records
D. expects to merge the records
Answer» B. expects to find fixed length record
discuss
38.

permission to access the file is controlled by

A. n/w structure
B. directory structure
C. access permissions
D. file structure
Answer» C. access permissions
discuss
39.

To the user,the unix system treats devices as if they are

A. devices
B. interfaces
C. hardware
D. files
Answer» D. files
discuss
40.

Two invocations copy copy.c newcopy.c copy copy newcopy

A. 1st is carrect
B. 2nd is carrect
C. both carrect
D. both wrong
Answer» C. both carrect
discuss
41.

In processing environment of unix

A. a program is an executable file and process is an instance of the program in execution
B. a process is an executable file and program is a instance of the process in execution
C. a process and program are both same
D. all above are carrect
Answer» A. a program is an executable file and process is an instance of the program in execution
discuss
42.

The fork system call

A. creates a new program
B. creates a new interface
C. creates a new hardware
D. creates a new process
Answer» D. creates a new process
discuss
43.

What command do you have to use to go to parent directory

A. cd-,
B. cd -
C. cd/up
D. cd..
Answer» D. cd..
discuss
44.

The command used to display a specified file

A. mkdir
B. chmod
C. cat
D. compress
Answer» C. cat
discuss
45.

root in unix system is represented by

A. %
B. \\
C. $
D. /
Answer» D. /
discuss
46.

what does cd.. Do ?

A. not a valid unix command
B. logs out of the computer
C. changes the working directory to login directory
D. " " " " " " the parent of current working directory
Answer» D. " " " " " " the parent of current working directory
discuss
47.

What does command LS do

A. opening a file
B. display contents of a file
C. display of file & folders, present in the folder where you are
D. shows a calender
Answer» C. display of file & folders, present in the folder where you are
discuss
48.

Why is PWD used

A. show current user
B. show present working directory
C. to display error messages
D. to copy files
Answer» B. show present working directory
discuss
49.

Which is the carrect command to list files & folders in unix

A. list
B. ls
C. dir
D. list files
Answer» B. ls
discuss
50.

How can you display a list of files including hidden files

A. find all
B. ls-a
C. ls-b
D. all answers a,b,c
Answer» B. ls-a
discuss
51.

Which command makes an empty directory

A. mkdirectory
B. makedirectory
C. mkdir
D. newdir
Answer» C. mkdir
discuss
52.

Why is man command used

A. to shut down
B. search all files
C. deleting files
D. getting help command on format
Answer» D. getting help command on format
discuss
53.

Which of the following features of unix may be used for interprocess communication

A. signals
B. pipes
C. semaphores
D. all of these
Answer» D. all of these
discuss
54.

In a system,if 5 people are currently using the vi editor,then the number of corresponding processes will be

A. 1
B. 5
C. 2
D. 0
Answer» B. 5
discuss
55.

The command echo welcome >/dev/tty

A. echoes welcome in all the terminals that are switched on
B. echoes welcome in all the " that are logged on
C. echoes welcome only in the terminal in which it is run
D. both (a) and ( c)
Answer» D. both (a) and ( c)
discuss
56.

/dev/null

A. is a file
B. has write permission for all
C. is the unix builtin dustbin
D. all of these
Answer» D. all of these
discuss
57.

The advantage of binary files over text files is that

A. it is compact
B. it can be accessed faster
C. they are more reliable
D. all of these
Answer» D. all of these
discuss
58.

The permission bits of a filenoname,can be set to - rws - - * - - * by the command

A. chmod 711 noname
B. chmod go -rw noname
C. chmod 2711 noname
D. none of above
Answer» D. none of above
discuss
59.

/bin/passwork 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
Answer» D. all of these
discuss
60.

If are does not 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 & b
Answer» D. both a & b
discuss
61.

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 & b
D. non of above
Answer» C. both a & b
discuss
62.

Consider the following program main ( )
{ printf ("Aayush won a football match on
\n"); system ("date");
printf("In Berlin"); } 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 a file out f
B. displays the output of date on the screen
C. prints everything on screen
D. prints the two messages on the screen
Answer» A. redirects the output of date to a file out f
discuss
63.

The Hardware at centre of UNIX system provides………….

A. basic services
B. operating system with basic services
C. kernel service
D. none of these
Answer» B. operating system with basic services
discuss
64.

Operating System is also called as ……….

A. system kernel
B. kernel
C. both a and b
D. none of these
Answer» C. both a and b
discuss
65.

Program such as Shell and editors interact with kernel by invoking ……….

A. process
B. thread
C. system calls
D. none of these
Answer» C. system calls
discuss
66.

…………responsible for exchanging data between kernel and programs

A. system calls
B. thread
C. process
D. none of these
Answer» A. system calls
discuss
67.

what is a.out ?

A. system user program
B. private user program
C. local program
D. none of these
Answer» B. private user program
discuss
68.

How many system calls in system V

A. 32
B. 64
C. 128
D. 16
Answer» B. 64
discuss
69.

Out of 64 system calls in system V how many are frequently used…

A. 64
B. 32
C. 16
D. 128
Answer» B. 32
discuss
70.

Non leaf node of the file system structure is …………..

A. leaf node of file
B. directory of file
C. regular file
D. path name
Answer» B. directory of file
discuss
71.

Full path name starts with …..

A. dot
B. slash
C. double slash
D. non of these
Answer» B. slash
discuss
72.

Text formatting program troff find …………. character at the end of each line

A. newline
B. slash
C. dot
D. none of these
Answer» A. newline
discuss
73.

System accounting program acctcom find ……….

A. variable length record
B. fixed length record
C. no record
D. none of these
Answer» B. fixed length record
discuss
74.

Directories are …….

A. fixed files
B. regular files
C. variable files
D. none of these
Answer» B. regular files
discuss
75.

System treats the data in a directory as a ……………..

A. byte stream
B. bit stream
C. stream
D. none of these
Answer» A. byte stream
discuss
76.

what is use of ls command ?

A. to list names and attribute of files
B. to list size of files
C. to list length of files
D. none of these
Answer» A. to list names and attribute of files
discuss
77.

Access permission can be set to …………

A. the file owner
B. a file group
C. everyone else
D. all of these
Answer» D. all of these
discuss
78.

The Newly created files are ………….. of the file system directory structure.

A. main nodes
B. root nodes
C. leaf nodes
D. middle nodes
Answer» C. leaf nodes
discuss
79.

Unix system treats devices as a ……..

A. hardware
B. file
C. byte
D. none of these
Answer» B. file
discuss
80.

Permission mode on newly created file will be……

A. 0666(octal)
B. 0666(hexadecimal)
C. 0999(octal)
D. 0798(hex)
Answer» A. 0666(octal)
discuss
81.

Permission mode 0666(octal) means…………

A. allowing all users acess to file for writing
B. allowing all users acess to file for reading
C. restrict to read and write
D. allowing all users access to file for reading writing
Answer» D. allowing all users access to file for reading writing
discuss
82.

All system calls return ……..if open or create call fails

A. -2
B. 0
C. 1
D. -1
Answer» D. -1
discuss
83.

The open and create system calls returns an integer called a ……….

A. file number
B. file discriptor
C. file variable
D. none of these
Answer» B. file discriptor
discuss
84.

File discriptor programs uses………………...

A. to delete file
B. to save file
C. for subsequent references for file
D. none of these
Answer» C. for subsequent references for file
discuss
85.

The read system calls return 0 when ………..

A. it reaches middle of file
B. it reaches end of the file
C. file is empty
D. none of these
Answer» B. it reaches end of the file
discuss
86.

When a process makes a system call ,its mode changes from………

A. user to kernel
B. kernel to user
C. restricted to unrestricted
D. unrestricted to restricted
Answer» A. user to kernel
discuss
87.

The new process called, child process gets a ………... return value from fork.

A. -1
B. 0
C. 2
D. 1
Answer» B. 0
discuss
88.

The child process invoke …….to execute program copy .

A. fork
B. execl
C. wait
D. printf
Answer» B. execl
discuss
89.

Which of the following system calls transforms an executable binary file into a process?

A. fork
B. exec
C. ioct1
D. longjmp
Answer» B. exec
discuss
90.

Which of the following file names can be found in more than one directory?

A. passwd
B. bin
C. date
D. none of the above
Answer» A. passwd
discuss
91.

The command that can be used to restrict incoming messages to a user is………..

A. mesg
B. halt
C. grep
D. sleep
Answer» A. mesg
discuss
92.

The sort command in UNIX ….

A. used to sort a file
B. used to sort the list of files in a directory
C. both a and b
D. none of the above
Answer» A. used to sort a file
discuss
93.

Which command is used to remove a directory?

A. rd
B. rmdir
C. dldir
D. rdir
Answer» B. rmdir
discuss
94.

The tail command in UNIX……

A. can be used to look at the tail or bottom of the file
B. can be used to display the list of last 10 files in the current directory
C. can be used to display the list of last 15 in the current directory
D. none of the above
Answer» A. can be used to look at the tail or bottom of the file
discuss
95.

Which command is used to remove a file ……

A. rename
B. mv
C. rm
D. del
Answer» C. rm
discuss
96.

Which command will be used with vi editor to append text at end of line?

A. a
B. i
C. a
D. l
Answer» A. a
discuss
97.

Which of the following command the file names in multiple columns?

A. is–x
B. is
C. is–1
D. is–f–x
Answer» B. is
discuss
98.

Which command is used to display the device name of the terminal you are using?

A. who
B. ls
C. tty
D. stty
Answer» C. tty
discuss
99.

Which command allows you to view your file 24 lines at a time ?

A. more
B. cat
C. pg
D. none of the above
Answer» A. more
discuss
100.

Which of the following is not a communication command?

A. write
B. mail
C. mesg
D. grep
Answer» D. grep
discuss
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