linux pppt for introduction of the Linux

An Introduction to Linux
Operating System
Mandeep & Ramzan

Content
 What is Linux
 Why Linux
 The Linux system
 Security
 OS Comparison

What is Linux
 Linux is a true 32 bit UNIX-like OS developed
originally for home PCs, but now it runs on a
variety of platforms including PowerPC,
Macintosh and many others. The source code for
Linux is freely available to everyone. Linux was
created by Linus Torvalds in 1991, and it has been
developed with the help of many programmers
across the Internet. Now it has evolved into a
very functional, powerful and usable clone of
Unix .

Why Linux
 A Linux Distribution has thousands of
dollars worth of software for no cost.
 Linux is a complete operating system:
• stable - the crash of an application is much less
likely to bring down the OS under Linux.
• Reliable - Linux servers are often up for
hundreds of days compared with the regular
reboots required with a Windows system.
• extremely powerful
 Linux provides a complete development
environment.

Why Linux (continued)
 Excellent networking facilities
 Ideal environment to run servers such as a web
server, or an ftp server.
 A wide variety of commercial software is
available if not satisfied by the free software
 Easily upgradeable.
 Supports multiple processors.
 True multi-tasking, multi-user OS.
 An excellent window system called X, the
equivalent of Windows but much more flexible.
 Full source code is provided and free.

The Linux System
 The Linux system excel in many area,
ranging from end user concerns such as
stability, speed, ease of use, to serious
concerns such as development and
networking.
• Linux kernel
• Linux networking
• Linux file system

Linux Kernel
 The kernel is the central nervous system of
Linux, include OS code which runs the
whole computer. It provides resources to all
other programs that you run under Linux,
and manages all other programs as they run.
• The kernel includes the code that performs
certain specialized tasks, including TCP/IP
networking.
• The kernel design is modular, so that the actual
OS code is very small to be able to load when it
needs, and then free the memory afterwards,
thus the kernel remains small and fast and
highly extensible.

Linux Networking
 Networking comes naturally to Linux. In a
real sense, Linux is a product of the Internet
or World Wide Web (www).
 Linux is made for networking. Probably all
networking protocols in use on the Internet
are native to Unix and/or Linux. A large part
of the Web is running on Linux boxes, e.g.
: AOL

Networking protocols
 The Linux kernel supports several
networking protocols:
• TCP/IP - Transport Control Protocol/Internet
Protocol
• IP is the primary network protocol supported by
Linux
• IPX - Internetwork Packet Exchange

Linux File System
 Linux has an hierarchical, unified file
system
 Supports 256-character filenames.
 All command line entries are case sensitive.
 Use the slash(/) rather than the backslash()
you have been using in DOS.

Types of File
 Ordinary files
• text files
• data files
• command text files
• executable files
 directories
 links
• rather than having multiple copies of a file,
Linux uses linking to one file to save disk space.
 special device files

Security
 Encryption
 Secure shell(ssh)
 Principles of security

Encryption
 Encryption commonly used to secure data.
It is the ancient technique of hiding
information in plain sight. Include:
• strong encryption - is stronger than the 40-bit
encryption maximum that can be exported from
the United States under U.S. law.
• Public-key Encryption - is a type of asymmetric
encryption, which is a system that you encrypt
your message with one key, and the recipient
decrypts it with a mathematically related, but
different key.

The Secure Shell(ssh)
 The ssh and its tools use strong encryption
to allow remotely located systems to
exchange data securely.
 By using strong encryption, ssh
significantly enhances the security of both
the authentication process and the session
itself.

Principles of security
 Two broad categories of attack exist:
• unauthorized access
• denial of service
 Defense against the attacks:
• enforce the use of password
• use TCP wrappers to limit which resources are
made available to which categories of users.
• monitor internal users, protect your organization
against unauthorized or inappropriate use of the
computer facilities to harass personnel.

Linux vs. Unix
 Linux is free, but Unix is not.
 Unix is compatible with Linux at the system
call level, meaning most programs written
for either Unix or Linux can be recompiled
to run on the other system with a minimum
of work. But Linux will run faster than Unix
on the same hardware.

Linux vs. Microsoft Windows
 Both offer some of the graphics capabilities
and include some networking capabilities.
But Linux networking is excellent.
 Linux is multi-user, multi-tasking, but
Microsoft Windows doesn’t support it.

Linux vs. Windows NT
 Linux needs 2MB RAM to try out, while NT needs
12 MB
 Linux needs at least 15 MB disk space, while NT
needs 70 MB at least.
 Both system support multitasking
 Both system support multiprocessing.
 Both system support dynamic cache.
 Linux has full multi user support. Local users,
modem users, and network users can all
simultaneously run text and graphics programs.
This is a powerful feature for business
environments that is unmatched by NT.

Linux vs.Windows NT(continued)
 The issue of size is a great strength for
Linux. It was designed to be as small and
efficient as possible. NT’s most important
criterion was portability.
 Linux was built on the Internet, and hence
has better support for networking then NT.
 Most software packages that run on Linux
have their source code available, security
problems are found and solved many times
quicker then with NT.

Reference
 http://www.Linux.org
 http://www.redhat.com
 http://www.google.com
 https://www.wikipedia.org

linux pppt for introduction of the Linux

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