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This set of Operating System Architecture Multiple Choice Questions & Answers (MCQs) focuses on Operating System Architecture Set 16
Q1 | which to mount the file system
- root
- boot
- mount-point
- partition
Q2 | Which command is used to mount file system read only.
- mount –a
- mount –v
- mount –f
- mount –r
Q3 | Each process has unique
- fd table
- file table
- inode table
- data block table
Q4 | File descriptor table indexes which kernel structure?
- struct file
- strruct fs_struct
- files_struct
- struct inode
Q5 | What is the default number of files open per user process?
- 0
- 1
- 2
- 3
Q6 | he file system information is stored in
- boot block
- super block
- inode table
- data block
Q7 | Switch table is used by
- device special file
- directory file
- fifo
- link file.
Q8 | What is the use of fcntl function?
- locking a file
- reading the file descriptor flag
- changing the file status flag
- all the above
Q9 | Which function can be used instead of the dup2 to duplicate the file descriptor?
- read()
- open()
- stat()
- fcntl()
Q10 | printf() uses which system call
- open
- read
- write
- close
Q11 | read() system call on success returns
- 0
- -1
- c)
- none
Q12 | Which system call is used to create a hard link?
- hardlink
- link
- symlink
- ln
Q13 | namei() is
- ansi c library function
- c library function
- system call
- kernel routine
Q14 | dup2(1,0)
- closes the stdout and copies the stdin descriptor to stdout
- closes the stdin and copies the stdout descriptor to stdin
- will produce compilation error
- none of the above
Q15 | What is stored in logfile as per below mentioned code if we execute ./a.out > logfile?nt main() {int fd; close(1);fd = open(“logfile”,O_RDWR, 0744); write(fd, “Hello”, 5); printf(“World\n”);return 0;}
- hello
- helloworld
- world
- none
Q16 | For the below mentioned codeint main() { int fd;fd = open(“logfile”, O_CREAT|O_RDWR, 0600);lseek(fd, 5, SEEK_CUR);write(fd, “Hello”, 5);return 0;},
- 5
- 1024
- 1029
- 1034
Q17 | Given a code snippet below? #define PERMS (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)int main() { int fd1, fd2; umask(0);fd1 = open(“file1”, O_CREAT | O_RDWR, PERMS)umask(S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);fd2 = open(“file2”, O_CREAT | O_RDWR, PERMS)return 0;}The newly created files file1 and file2 will have the permissions respectively
- rw-rw-rw- r——–
- r——– rw-rw-rw-
- rw-rw-rw- rw——
- none of the abov
Q18 | Below is the codeint main() { int fd1, fd2;struct stat buff1, buff2;fd1 = open(“1.txt”, O_RDWR); fd2 = open(“2.txt”, O_RDWR | O_APPEND);lseek(fd1, 10000, SEEK_SET);write(fd1, “abcdefghij”, 10);write(fd2, “abcdefghij”, 10); fstat(fd1, &buff1);fstat(fd2, &buff2);printf(“ %d %d”, buff1.st_size, buff2.st_size);return 0;}Before running the program, the file 1.txt and 2.txt size is 20 each. What is the output?
- 30 30
- 100020 20
- 100030 30
- 100010 30
Q19 | ode snippets str1=”45678\n” str2=”123\n”f1 = fopen(file1,RDWR,RWX) f2 = fopen(file1,RDWR,RWX) write(f1,str1,len_str1) write(f2,str2,len_str2)o/p:
- 12378
- 123(newline)8(new line)
- 123(newline)78(ne wline)
- 45678(newline)1 23(newline)
Q20 | Code snippet (file1 size is 2024)f1 = fopen (file1, RDWR, RWX)lseek(f1,1024,SEEK_SET) write(f1,buf,10)What is offset now.
- 1024
- 1034
- 2034
- 2054
Q21 | what is file system
- seqenceof bytes
- sequence of bits
- sequence of kilo bytes
- sequence of megabytes
Q22 | The parent directory is known as
- root
- bin
- user
- none of these
Q23 | user on unix system is alled as
- unique user
- super user
- special user
- all of these
Q24 | the different pemissions asociated with files are
- read
- write
- execute
- all ofthese
Q25 | The command - in ls represents
- accessibility of a file
- permissin on the file
- reead
- execute