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CUSTOMER_CODE
SMUDE
DIVISION_CODE
SMUDE
EVENT_CODE
JAN2016
ASSESSMENT_CODE BC0056_JAN2016
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
5311
QUESTION_TEXT
Write a short Note on
i. Devices
ii. Links
iii. HomeDirectory
iv. The Current Directory
v. Parent Directory
SCHEME OF
EVALUATION
i.Devices: To provide applications with easy access to hardware devices.
UNIX allows them to be used in much the same way as ordinary files.
There are two types of devices in UNIX- block-oriented devices which
transfer data in blocks and character – oriented devices that transfer data
on a byte-by – byte basis.
ii.Links: A link is a pointer to another file. There are two types of links –
ahard link to a file is indistinguishable from the file itself. A soft link
provides an indirect pointer or shortcut to a file. A soft link is
implemented as a directory file entry containing a pathname.
iii.The Home Directory: UNIX provides each user his own directory
known as “home” directory. Within this, the users can store their own
files, create subdirectories. This directory and its content is exclusive of
the respective user.
iv.The current directory: The current directory can be referred to by
character (a full stop). This refers to your actual location in the file store
hierarchy. When you log in, the current directory is set to your home
directory.
v.The Parent Directory: The parent directory is the directory
immediately above the current directory. The parent directory can be
referred to by the characters (two full stops). For example, to refer to the
file test in the parent directory:../testRelative path names may also be
constructed by progressively stepping back through parent directories
using the construct.
(2 marks each)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
72491
QUESTION_TEXT
Explain the following Directory and file handling commands in
UNIX with their syntax.
i. cp
ii. mv
iii. rm
iv. cd
v. cat
SCHEME OF
EVALUATION
i. cp: cp is used to make copies of files or entire directories…..
ii. mv: mv is used to rename files/directories and/or move them
from one directory into another……
iii. rm: removes the specified files………….
iv. cd: changes your current working directory to path…………..
v. cat: displays the contents of target-file(s) on the screen, one
after the other…….
Each 2 marks (syntax – 1, explanation -1)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
72495
QUESTION_TEXT
List and give the meaning of any 5 predefined special shell
variables.
Any 5 variable with meaning – each 2 marks
SCHEME OF
EVALUATION
QUESTION_TYPE DESCRIPTIVE_QUESTION
QUESTION_ID
72497
QUESTION_TEXT What are the layers of UNIX operating system? Explain.
SCHEME OF
EVALUATION
The UNIX system is actually more than strictly an operating system.
UNIX includes the traditional operating system components. In addition,
a standard UNIX system includes a set of libraries and a set of
applications. Sitting above the hardware are two components: the file
system and process control. Next is the set of libraries. On top are the
applications. The user has access to the libraries and to the applications.
These two components are what many users think of as UNIX, because
together they constitute the UNIX interface.
The part of UNIX that manages the hardware and the executing processes
is called the kernel. In managing all hardware devices, the UNIX system
views each device as a file (called a device file). This allows the same
simple method of reading and writing files to be used to access each
hardware device. The file manages read and write access to user data and
to devices, such as printers, attached to the system. It implements security
controls to protect the safety and privacy of information. In executing
processes, the UNIX system allocates resources (including use of the
CPU) and mediates accesses to the
hardware.
(10 marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
111205
QUESTION_TEXT
In how many phases Fsck conducts a check? Briefly explain
them.
Phase 1 to 5 Explanation – Each 2 marks (10 marks)
SCHEME OF
EVALUATION
QUESTION_TYPE DESCRIPTIVE_QUESTION
QUESTION_ID
QUESTION_TEXT
SCHEME OF
EVALUATION
111214
Explain the mounting and un-mounting process in UNIX
The mount Command
(5 marks)
The basic format of mount command:
# mount device mountpoint
Options:
-a: Mount all the file systems listed in /etc/fstab. Except those marked as
noauto keyword excluded by the -t flag, or those that are already
mounted.
-f: Forces the mount of an unclean file system (dangerous), or forces the
revocation of write access when downgrading a file system’s mount
status from read-write to read-only.
-r: Mounts the file system read-only.
-t fstype: Mounts the given file system as the given file system type
-U: Update mounts options on the file system.
-v: Be verbose. -w: Mounts the file system read-write.
Unmount: Un-mounting File Systems (5 marks)
Unmounting is achieved with the unmount command which requires
either the file system name or the mount point as argument.
umount /oracle
umount /fdev/hda3
umount/dev/dsk/cOt3dOs5
Unmounting a file system is not possible if you have a file open in it.
Further, just as you can’t remove a directory unless you are placed in a
directory above it, you can’t unmount a file system unless you are placed
above it. All forms take -f to force unmounting, and -v for verbosity. -a
and -A are used to unmount all mounted file systems, -A, however, does
not attempt to unmount the root tile system.