chapter 1 intro to linux

7/31/2019 Chapter 1 Intro to Linux

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LP 8

OPERATING SYSTEM

IMPLEMENTATION


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Operating System

Linux is a Unix like-operating system

Operating system:interface betweenhardware and software

Task perform by OS:

Processor management

Memory management.

Device management.

Storage management.

Application interface.

User Interface


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Type of Operating System

Real-time operating system

often found in roboticmachinery and scientific

devices

Single-user, single task

system

used by devices such as

a PDA or other miniaturecomputers.

allows one user to operate

one program at a time


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Single-user, multitasking

system

user can open multipleprograms and jump

back and forth

between applications

as required

Multi-user systemallows many users to

access the computer's

resources

simultaneously


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OS strategy as described by Nutt

Batch

Timesharing

Personal computing

Dedicated


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Batch Processing

is execution of a series ofprograms ("jobs") on a computerwithout manual

intervention.
http://en.wikipedia.org/wiki/Computer_programhttp://en.wikipedia.org/wiki/Job_(software)http://en.wikipedia.org/wiki/Computerhttp://en.wikipedia.org/wiki/Computerhttp://en.wikipedia.org/wiki/Job_(software)http://en.wikipedia.org/wiki/Computer_program


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Personal Computing

This strategy supports a single user running

multiple programs on a dedicated machine.

Since only one person is using the machine,

more attention is given to establishing

predictable response times from the system. This strategy is quite common today because of

the popularity of personal computers.


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Timesharing

is the sharing of a computing resource among

many users by means ofmultiprogramming andmulti-tasking.

This strategy supports multiple interactive users.
http://en.wikipedia.org/wiki/Multiprogramminghttp://en.wikipedia.org/wiki/Computer_multitaskinghttp://en.wikipedia.org/wiki/Computer_multitaskinghttp://en.wikipedia.org/wiki/Multiprogramming


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Dedicated

supports real-time and process control systems

This strategy supports real-time and processcontrol systems.

These are the types of systems which control

satellites, robots, and air-traffic control.

The dedicated strategy must guarantee certain

response times for particular computing tasks or

the application is useless.


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Examples of OS

Mac OS X

Microsoft Windows

DOS

Linux

Cisco IOS

Netware


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Linux Evolution

Richard Stallman- founded theGNU Project

Goal: developing a completeUnix-like operating systemcomposed entirely of freesoftware

Dont have the corecomponent;- kernel

The GNU project begandeveloping a kernel, the GNU

Hurd, in 1990, based on theMach Microkernel, but thedevelopment of this Mach-based design proved difficultand proceeded slowly


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another kernel was begun as a

hobby by Finnish university

student Linus Trovalds Torvalds originally used Minix

on his own computer, a

simplified Unix-like system

written by Andrew Tanenbaumfor teaching operating system

design.

However, Tanenbaum did notpermit others to extend his

operating system, leading

Torvalds to create a

replacement for Minix


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Uniqueness of Linux

Free

entirely open source

come with a 'free software license' in order to

guarantee it


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Comparison between Linux and Windows or OS X

Security fast fixing of bugs, and relative obscurity

Hardware support

Linux runs on a huge variety of hardware, ranging fromsupercomputers to networking routers to smart phones.

Multimedia supportCommercial distributions will usually include licensed,

proprietary media plug-in to enable support for WindowsMedia Files, Flash, Java, Quicktime, DVD video, etc


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The GNU Movement and the GPL

GNU (GNU is Not Unix) tools are in every Linux

distribution Provided by the Free Software Foundation

(FSF), founded by Richard Stallman

Advocates freedom of software

Ideas present in GNU General Public License

(GPL)


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GPL

GNU General Public License (GPL) is using free

software license.

Originally written by Richard Stallman

GNU Lesser General Public License (LGPL) -

modified version of the GPL, intended for somesoftware libraries.


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In contrast, the end-user licenses (EULA) that

come with proprietary software generally only

grants the end-user the right to copy the

software onto a limited number of computers


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The usages of GPL - to grant the recipients of a

computer program the following rights:

to run the program, for any desired purpose.to run the program, for any desired purpose.

to study how the program works, and modifyto study how the program works, and modifyit.it.

to redistribute copies.to redistribute copies.

to improve the program, and release theto improve the program, and release theimprovements to the public.improvements to the public.


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Introduction to Linux Kernel

Core (heart) of the operating system

allocates machine resourcesincludingmemory, disk space, and CPUcycles.


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Linux operates in two modes--the Kernel mode

(kernel space) and the User mode (user space)

Linux Kernel Modules

monolithic kernel

micro kernel


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Monolithic kernel

one single large program where all the functional

components of the kernel have access to all ofits internal data structures and routines.

Micro kernel structure where the functional pieces of the

kernel are broken out into units with strict

communication mechanism between them.


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Kernel Version

The version number of the Linux kernel consists

of four numbers. For illustration, the version number is composed

as A.B.C.D

A Denotes the kernel version.

It is changed only when major changes in the

code and the concept of the kernel occur.


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B

Denotes the major revision of the kernel version.

Before the Linux 2.6.x series, even numbers indicate a

stable release.

Odd numbers have historically representing

development releases testing for the new features.


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C

Indicates the minor revision of the kernel.

Changed when new features or new drivers

are added.

D

Represents correction. Security patches and bug (i.e., error) fixes.

Sometimes it will be followed by several letters,

such as rc1, ac, ck and mm. The letters rc (followed by a number) refer to a

release candidate and indicate a non-official

release.


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LinuxDistribution

Also called distro.

A Linux Distribution is created by individuals,

groups and organizations from around the world.


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Some of the common Linux distro: Red Hat Enterprise Linux Mandrake Linux The Fedora Project Knoppix

SUSE Linux Slackware Linux PCLinuxOS


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OPERATING SYSTEM

LAYERS

chapter 1 intro to linux

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