Sample Paper NOS

 

Time: 3 Hrs.                                                                                           Max Marks. : 100

 

 

Note:        Attempt any FIVE questions

                  All questions equal marks.

 

1. (a) Explain UNIX Architecture.

(b) What is 'inode'?  Explain in detail.

(c) Differentiate Between A Systems Call And A Library Function Giving Two  

      Examples For Each (System Calls Should Be Other Than File System Calls.)

 

                                                                                                                      (7+6+7)

2.  (a)  Describe the file structure of Unix system, How will you determine the

             maximum number of files a file system can contain ?

(b)    Differentiate between kernel mode and user mode in UNIX.

(c)     List five system calls used for IO operations.

(d)    Compare the permissions a process must have for the following operations and comments.

(i)       Creating a new file requires write permission in a directory

(ii)  Creating an existing file requires write permission on the file

(iii)  Unlinking a file requires write permission in the directory, not on the file.                                                                                              ( 8+3+3+6)

 

3. Explain the following commands by giving their description and syntax.

       (a)    pwd              (b)  chmod         (c)   head          (d) ln

       (e)    tty                 (f)   find             (g)  chown           (h) Who           

 (i)     tail                 (j)   mv                                                                        (2*10)

           

 

4.       (a)  Differentiate between environment variables and User defined variables   

                        in Unix.

(b)    Write three different shells used by UNIX. Explain how they differ.

(c)     Explain the significance of the following positional parameters :-

          (i)         $*                             (ii)        $?                        (iii)        $#

                                                                                                                       

(d)    Explain the following shell commands

           (i)  export                (ii) set                      (iii) shift                    (4+4+4+6)

 

      6.          (a)   What are the major responsibilities of a system Administrator ?

                   (b)   Differentiate between   mounting and unmounting of a file system ?

                    (c)  What are links and symbolic links in UNIX file system?

                  (d)   How do you change File Access Permissions? Explain with examples                 

(4+4+4+8)

 

5.       (a)  Explain structures used for iteration in shell programming with suitable  

                    examples.

(b)    Write a shell script to generate a multiplication table of a given number .

(c)     Write a shell script to delete all the “mp3” files under your home directory.

(d)    What are environment variables?

                                                                                                           ( 5+6+6+4)

 

 

       7.          (a)    What is the use and syntax of make command ?

                             Discuss the rules and macros of make utility.

(b)          Explain the lex and yacc utilities of Unix. Give two regular expressions and two grammar rules represented in the specifications of lex and yacc respectively.

(c)           What do nroff, tbl, and pic are used for ? Give examples of each.

(d)          What do Dbx and Adb do ? Explain briefly.               (5+6+6+3)