Transcript to View - Jashbhai Maganbhai Patel College of Commerce

Created By: Asst. Prof. Ashish Shah, J.M.Patel
College of Commerce
CHAP-1 INTRODUCTION TO LINUX
UNIT-I
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Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
INTRODUCTION TO LINUX
Linux is a freely distributed implementation of a
UNIX-like kernel, the lowlevel core of an operating
system.
 Because Linux takes the UNIX system as its
inspiration, Linux and UNIX programs are very
similar. In fact, almost all programs written for
UNIX can be compiled and run on Linux. Also,
some commercial applications sold for commercial
versions of UNIX can run unchanged in binary form
on Linux systems
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Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
WHAT IS KERNAL?
Linux, itself is the core of the operating system:
the kernel. The kernel is the program acting as
chief of operations.
 It is responsible for starting and stopping other
programs (such as editors), handling requests
for memory, accessing disks, and managing
network connections.
The kernel is a nontrivial program.
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Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
GNU: NOT A UNIX, BUT UNIX BASED O.S.
The Linux community (together with others)
supports the concept of free software, that is,
software that is free from restrictions, subject to
the GNU General Public License (the name GNU
stands for the recursive GNU’s Not Unix).
 Although there may be a cost involved in obtaining
the software, it can thereafter be used in any way
desired and is usually distributed in source form.
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Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
PROJECT BASED ON GNU
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A few major examples of software from the GNU Project
distributed are as follows:
GCC: The GNU Compiler Collection, containing the GNU
C compiler
G++: A C++ compiler, included as part of GCC
GDB: A source code–level debugger
GNU make: A version of UNIX make
Bison: A parser generator compatible with UNIX yacc
bash: A command shell
GNU Emacs: A text editor and environment
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Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
LINUX DISTRIBUTION
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Linux distributions can be broadly categorized into two
groups.
The first category includes the purely commercial
distros, and the second includes the noncommercial
distros, or spins.
The commercial distros generally offer support for their
distribution—at a cost. The commercial distros also tend
to have a longer release life cycle.
Examples of commercial flavors of Linux-based distros
are RHEL, SuSE Linux Enterprise (SLE), etc.
The noncommercial distros, on the other hand, are free .
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Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
DUTIES OF LINUX ADMINISTRATOR
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the Linux system administrator is the person who has
“root”access, which is to say the one who is the system’s
“super user” (or root user).
The “root” user has unfettered access to everything all user
accounts, their home directories, and the files therein; all
system configurations; and all files on the system.
System administrator has full system privileges,
No one should ever log in as “root,” because system
administration tasks can be performed more easily and safely
through other, more specific means.
Compare to it a standard Linux user is limited as to the things
he or she can do with the underlying engine of the system.
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Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
DUTY OF ADMINISTRATOR FOR INSTALLING AND
CONFIGURING SERVERS
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Linux server runs even on a standalone machine with one user
account. It must be configured.
Linux is a multiuser operating system. Each user has (or shares) an
account on the system, be it on a separate machine or on a single
machine with multiple accounts.
One reason that these concepts are crucial is found in the
administration of application software — productivity programs.
While it is possible for individual users to install some applications in
their home directories — drive space set aside for their own files and
customizations — these applications are not available to other users
without the intervention of the system administrator.
Besides, if an application is to be used by more than one user, it
probably needs to be installed higher up in the Linux file hierarchy,
which is a job that can be performed by the system administrator
only. (The administrator can even decide which users may use which
applications by creating a “group” for that application and enrolling
individual users into that group.)
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Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
DUTY OF ADMINISTRATOR FOR CREATING AND
MAINTAINING USER ACCOUNTS
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No one can show up and log on to a Linux machine.
The system administrator can only create an account for every
user and gives permission for respective tasks such as
accessing files, editing of files etc.
A system administrator can access all accounts as it login as
root and can performs some administrative tasks which include
creating and manipulating user accounts ( add, modify, delee
or copy user accounts), change password whenever it requires,
defining group of related users which can share access to a file
or directory and providing access to connect to server.
Administrator is responsible for maintaining security by
providing role on a user account that defines a level of access.
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Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
DUTY OF ADMINISTRATOR FOR BACKUP AND
RESTORING FILES
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there is a need to back up important files so
that in the event of a failure of hardware,
security, or administration, the system can be
up and running again with minimal disruption.
Only the system administrator may do this.
(Because of its built-in security features, Linux
may not allow users to be able even
to back up their own files to floppy disks.)
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Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
DUTY OF ADMINISTRATOR FOR BACKUP AND
RESTORING FILES
To minimize the disruption of data,
administrator maintains backups of files, to
restore them whenever required.
 Baking up files is one of the most critical tasks
in system administration.
 Administrator maintains proper and regular
back ups to prevent damage to data.
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Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
DUTY OF ADMINISTRATOR FOR MONITORING
AND TUNING PERFORMANCE
It is a essential parts of administration to keep
linux working more efficiently.
 Sysem tuning is an unending practice supported
by a variety of diagnostics and monitoring tools.
 To get good idea of how a system is performing,
CPU, memory, I/O, and network needs to be
monitored.
 For maintaing efficient performance tuning it
requires to understand how various computer
modules communicate.
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Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
DUTY OF ADMINISTRATOR FOR CONFIGURING
SECURE SYSTEM
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It is a most important task of administration. For this excellent
task and decision requires to run a secure linux sysem and
maintaining data integrity.
Administrator makes sure that a user or program can perform
only those actions that they are allowed to perform. For this
administrator must
Make sure that system has firewalls
Not allow connections from unknown networks, if possible.
Block all unnecessary services on linux system.
Only that software have to be loaded which is must require,
otherwise do not install useless software.
Must configure network, system application and services to
maintain secuirty and should be aware of the tools which can
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be used to monitor hacker threats.
Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
FILE SYSTEM OF LINUX
The term mount point refers to the directory
you associate with a disk partition or any other
device.
 Suppose that you have two disks on your PC,
and you have created Linux partitions
 on both disks. Figure below illustrates how you
can mount different parts of the Linux directory
tree (the file system) on these two partitions.
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Created By: Asst. Prof. Ashish Shah,
J.M.Patel College of Commerce
FIGURE :MOUNTING THE RED HAT LINUX FILE
SYSTEM ON TWO DISK PARTITIONS
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