Transcript Introduction to Operating System

In The Name Of
Allah
Whose Blessings Are
Uncountable.
Introduction to Operating
System
Abdul Hameed
Assistant Professor
http://informationtechnology.pk
www.facebook.com/it4all.pk
3
Lecture Overview
• Operating System Concepts
• Disk Partitioning
• Primary/ Extended /Logical Partition
• Formatting
• FAT / NTFS
• NTFS Securities
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System Software
• What is system software?
Programs that
control operation
of computer
Two types are
operating systems
and utility programs
Operating system (OS)
(sometimes called the platform)
coordinates all activities
among computer
hardware
resources
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Operating Systems
• Functions of an operating system?
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start the computer
provide a user interface
manage programs
administer
security
manage
memory
control a
network
provide file
management and
other utilities
monitor
performance
establish an Internet
connection
schedule jobs and
configure devices
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
Operating System
Software that controls a computer and acts as a layer
between the hardware and the applications and users. (eg.
Linux, Windows, Mac OS X, Unix);

Software that provides a simple environment / Interface
for programmers and end users to work more efficiently
(shell, command interpreter)
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
Operating System: User interface
Controls how you enter data and instructions and how
information displays on screen
command-line interface
menu-driven interface
Difficult to remember and use
Give more control
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
Operating System: Graphical user interface (GUI)
User
interacts
with menus
and visual
images such
as icons and
buttons
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Operating System:
Single user/ Single tasking


Working on one programs by one user
Like DOS OS
Single user/ multitasking


Working on two or more programs that reside in
memory at same time
Like Windows XP
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

Operating System: Network operating system
Allows users to share printer, Internet access, files,
and programs on a network
Administers security by establishing user name and
password for each user
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
Operating System: Types
Some characteristics of operating systems
Proprietary
software
Devicedependent
Runs only on specific
type of computer
Privately owned and
limited to specific vendor
or computer model
Downward
compatible
Works with application
software written for earlier
version of operating system
Deviceindependent
Runs on many
manufacturers’
computers
Upward
compatible
Runs on new versions of
operating system
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



Operating System: Categories

Windows CE.net
Pocket PC 2002
Palm OS
Symbian OS











DOS
Win 3.x,95, 98,2000
professional, Me, NT
workstation, Windows XP
Mac OS X
OS/2
UNIX
Linux
Embedded
Netware
Windows NT Server, 2000
Server, 2003
OS/2 Warp Server
UNIX
Linux
Solaris
Network
Stand-alone
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Network Operating System
•Examples of
NetWare
network
operating systems
Designed for
client/server
networks
Linux
Windows
Server 2003
Multi-purpose
operating system
Upgrade to Windows
2000 Server
Solaris
 Version of UNIX
developed by Sun
Microsystems
 Specifically for
e-commerce
applications
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Introduction to Disk
Partitions
Abdul Hameed
Assistant Professor
http://informationtechnology.pk
www.facebook.com/it4all.pk
15
Disk Management: Primary Partition
• A volume you create using unallocated space on a basic disk.
Windows 2000 and other operating systems can start from a
primary partition.
• You can create up to four primary partitions on a basic disk, or
three primary partitions and an extended partition.
• Primary partitions can be created only on basic disks and
cannot be sub partitioned.
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Disk Management: Extended Partition
A portion of a basic disk that can contain logical
drives.
One can extended partition if one want to have more
than four volumes on your basic disk. Only one of the
four partitions allowed per physical disk can be an
extended partition.
Extended partitions can be created only on basic
disks.
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Disk Management: Logical Partition
• A volume you create within an extended partition on
a basic disk.
• A logical drive can be formatted and assigned a drive
letter.
• Only basic disks can contain logical drives, and a
logical drive cannot span multiple disks.
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Disk Management: Partition Table
 On master boot record (MBR) disks, you can create up to four
primary partitions, or you can create up to three primary
partitions and one extended partition. Within the extended
partition, you can create unlimited logical drives.
 On GUID partition table (GPT) disks, you can create up to
128 primary partitions. Because GPT disks do not limit you to
four partitions, you do not need to create extended partitions
or logical drives.
Abdul Hameed
Introduction to File System
Abdul Hameed
Assistant Professor
http://informationtechnology.pk
www.facebook.com/it4all.pk
20
File Systems
File systems are a data structure or a collection of
files used by the operating system (i.e Windows,
Mac OS) to organize data and programs.
FAT 16
FAT 32
NTFS
EXT2
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File Systems: FAT 16
Used for DOS, Windows 3.1x
Maximum partition size is 4GB
Maximum File size is 2GB
OS like Unix, Linux, OS/2, Windows also read
FAT16
That is why suitable in case of Multi boot option.
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File Systems: FAT 32
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◦ Introduced in 1996 with windows 95
◦ Maximum partition size is 2TB
◦ Maximum File size is 4GB
◦ Improving the disk space usage by reducing the size of
cluster
◦ Do not provide

Security

Encryption

Disk Quota

Compression
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File Systems: NTFS
Provide local security of files and folders
Compression to save the disk space
Disk quota management to manage the storage
Encryption for additional security
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File Systems: NTFS: Advantages
 With NTFS, individual files and folders can have assigned Access Rights, enabling the
user to have greater control over the security in the system.
 NTFS supports data compression and encryption for files and folders, allowing the user
to save space on his hard drive and keep his files more secure.
 The largest file that can be saved using FAT32 is 4 Gigabytes. With NTFS there is no
such limit.
 On large drives with many files, the performance of a FAT32 drive suffers. NTFS drives
do not have a problem handling many files.
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File Systems: NTFS: Advantages
 This new file system also facilitates indexing of file contents,
which makes it far faster to do things such as use the Windows
Find/search function to seek a word processing document by
looking for a word buried deep in its text.
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File Systems: NTFS: Advantages
 Microsoft has tested NTFS with a single partition of up to 19 Terabytes (TB), but the
theoretical maximum is at least 8 Petabytes (PB).
 By contrast, FAT32 is effectively limited to volume sizes of 2TB (although this point is
debatable, and this is a theoretical maximum).
 One of the big differences is that FAT32 doesn't scale as well as NTFS. The larger the
volume size in FAT32, the larger the cluster size. At 64GB, FAT32 moves up to 16K
clusters. Even a 512byte file uses 16K of space just to exist under FAT32 on a 64GB
volume. That means FAT32 does not store data efficiently on larger volumes.
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File Systems: NTFS: Advantages
 NTFS is able to keep to its 4K cluster size default even on huge disk
volumes.
 Link tracking. You know how under Win98 if you create a desktop shortcut
for something, if you move that target file, the shortcut is broken? Not so
under XP with NTFS, which can dynamically update file shortcuts by
automatically searching for the new location of the target file.
Abdul Hameed
Introduction to Profiles
Abdul Hameed
Assistant Professor
http://informationtechnology.pk
www.facebook.com/it4all.pk
29
Profiles
 Contains the configuration information related to the user
and it contains User’s Desktop arrangement
Program Items
Personal Program Groups
Network and printer connections
Screen colors
Mouse settings
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Profiles
 Windows Explorer
 View of windows Explorer
 Mapped network drives etc.
 Control Panels
 Accessibility options
 Keyboards and mouse preferences
 Taskbar
 All settings including program items and their properties
 Accessories
 Preference settings for Calculator, Command Prompt, notepad etc.
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 Online Help bookmarks
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Profiles
 Users Profiles are useful when multiple users share the same
computer.
 User Profiles can be used by a single user or by group of users
 Three types of users profiles
Local User Profiles
Roaming User Profiles
Mandatory user Profiles
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Profiles: Local User Profile
First time the user logon the user receive the default
user profile.
Created on the local computer under the folder
‘Document and Setting’ and match with the user
name
Contains the files NTUSER.DAT file and some
subfolders contain the link to user’s Desktop items.
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Profiles: Drawbacks of Local User Profile
Available only on the computers where
they were created.
How to overcome the drawback?
By using Roaming User Profiles
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Profiles: Roaming User Profile
 Stored on the Server and accessible from any client
 When a user logon to client, a roaming profiles from server downloaded to
local computer
 When logoff or shutdown the client, roaming profile uploaded/saved on the
server
 If the roaming profile inaccessible from the server then local user profile is
used.
 In this way the roaming profile moves as the user moves in the network.
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Profiles: Roaming User Profile: How to?
 Create the local user profile that will be used as roaming user profile
 Create user, login as new user, customize it.
 Create a folder on the server and share the newly created folder
 Copy the profile to the server shared folder (under the User Profile tab of
System Properties choose the Copy To option)
 E.g. \\server1\profiles\abc (where server1 is name of server, profiles is the
shared folder and abc is name of user.
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Profiles: Roaming User Profile: How to?
Select user under the local user and groups
utility-right click – properties – profile tab and
enter the path of the profile.
i.e. \\server1\profiles\abc
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Profiles: Mandatory User Profile
 A roaming profile that cannot be modified by the user is called
Mandatory user profile.
 Mandatory profiles are stored in the file named as
NTUSER.MAN as compare to NTUSER.DAT of Roaming
profile
 A user can change the profile but it cannot be saved on the
server when he logoff.
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Profiles: Mandatory User Profile: How to?
 Create the local user profile that will be used as mandatory user profile
 Create user, login as new user, customize it.
 Create a folder on the server and share the newly created folder
 Rename the file NTUSER.DAT to NTUSER.MAN
 Copy the profile to the server shared folder (under the User Profile tab of
System Properties choose the Copy To option)
 E.g. \\server1\profiles\abc (where server1 is name of server, profiles is the
shared folder and abc is name of user.
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Profiles: Mandatory User Profile: How to?
 Select user under the local user and groups utility-right click –
properties – profile tab and enter the path of the profile.
 i.e. \\server1\profiles\abc
Abdul Hameed
Introduction to Groups
Abdul Hameed
Assistant Professor
http://informationtechnology.pk
www.facebook.com/it4all.pk
41
Groups: Importance

Groups are used to logically organize the users with similar rights.

Assign the permission to groups instead of many users

By adding users to groups, the users will get all the permissions of
the Groups

Similarly by removing the permission from the group will revoke
the relevant permissions from all the users of the groups.

Groups simplify troubleshooting
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

Groups: Default Groups
Administrators Group

Has full permissions

Can grant themselves the required permissions
Backup Operators

Has permission to backup and restore the file system even if they don’t
have NTFS permission

Does not have direct access to all the file system – Only through backup
utility
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Groups: Default Groups
 Guests

Has limited access to the computer

Used for the users who are not regular

Most administrator don’t allow guest access.
 Power Users

Has fewer access than Administrators e.g.

Create local user and groups

Create and delete network shares

Create manage local printers

Stop/start services etc.
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Groups: Default Groups
 Replicator

Support directory replication

Only domain users can be a member of Replicator Group
 Users

Have very limited system access.
Abdul Hameed
Introduction to NTFS Permission
Abdul Hameed
Assistant Professor
http://informationtechnology.pk
www.facebook.com/it4all.pk
46

NTFS Permissions
Control access the permission to NTFS folders
and files

Allow and Deny permissions

Deny overrides allow

Permission are Cumulative
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NTFS Permissions: Full Control

Traverse folder and execute file

List folder’s content and read the files in it.

See the folder’s or file’s attributes

Change the folder’s or file’s attributes

Create new files and overwrite data to the files.

Create new folder and append data to file

Delete subfolders and files

Delete files

Change permission for files and folder

Take ownership
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NTFS Permissions: Read, Execute

Traverse folder and execute files

List the contents of folder and read data in
files

See the folder’s or file’s attribute
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
NTFS Permissions:
Read

List the contents of folder and read the data in the
folder’s files


See the folder’s or file’s attributes
Write

Change the file’s or folder’s attribute

Create new files and write data to files

Create new folders and append data to files
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NTFS Permissions: Inherited
 By default parent folder permission are also applied to the subfolders or
files in that folder
 These are called the inherited Permission
 Inherited Permission are displayed in grayed check mark.
 One can override the permission inheritance (Stop inheritance) for the
folder by un-checking the allow inheritable permission from parent to
propagate to this object.
 You will then be given the choice of either to copy or remove the
permission previously inherited by the object.
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NTFS Permissions: Files are Copied or Moved
 Move files

If moved within the same NTFS volume the NTFS permission retained
as original.

If move file or folder to another folder of different volume the file is
treated as copy and will have the same permission as the destination
folder
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NTFS Permissions: Files are Copied or Moved
 Copy files

If the file or folder copied on another folder (either on
the same volume or different volume) the file will have
the same permission as of destination folder.

If copied or moved file to FAT volume, it will not retain
any NTFS permission
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