the gnu/linux operating system

8/8/2019 The GNU/Linux Operating System

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The Making of GNU/Linux Includes

The development of GNU applications

Failure of the GNU micro kernel project Integration of Linux kernel to the GNU

applications

The GNU Logo >>


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History of GNU In late 1970's, the computers were very

large, rare and can been seen only in large

Labs. Each of such computers had their own OS

and researchers worked on improving it as

a community. Richard Mathew Stallman was one of the

workers in the MIT Artificial Intelligence lab.


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The community was enhancing thefunctioning of the Time Sharing OS (ITS)

used in PDP-10 manufactured by DEC

His words follows...

History of GNU


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We did not call our software free software,

because that term did not yet exist; but thatis what it was. Whenever people fromanother university or a company wanted toport and use a program, we gladly let them.If you saw someone using an unfamiliar andinteresting program, you could always askto see the source code, so that you couldread it, change it, or cannibalize parts of itto make a new program.


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PDP-10


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The AI lab hacker community collapsed, as in1981, the company Symbolics had hired away

nearly all of the hackers from the AI lab Also, when the AI lab bought a new PDP-10 in

1982, its administrators decided to use

Digital's non-free timesharing system insteadof ITS.

Stallman resigned from MIT and started

writing codes for the GNU project to build anentire free Operating System. GNU stands for GNU is Not UNIX


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The Contributions The GNU project started of with the GCC

compiler

Later came GNU Emacs a text editor BASH The Shell

GNOME The graphical user environment HURD The Micro Kernel

And many more from the supporters


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The GNU softwares became popular and

was widely used in UNIX systems By 1990, the GNU system was almost

complete; the only major missing

component was the kernel. GNU HURD; the project for kernel

development started in 1990, but due to the

complex architecture and message passingfeatures, it was not completed in time. HURD developments still continues...


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History of Linux Almost the same time, when GNU started,

DOS was the most used OS in PC's.

The other one; UNIX was more expensive. The source code of Unix, once taught in

universities courtesy of Bell Labs, was now

cautiously guarded and not publishedpublicly.


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The history of Linux really start with MINIX MINIX was written from scratch by Andrew S

Tanenbaum, a professor who wanted to teach hisstudents the inner working of OS

Around 12,000 lines of code

Written in C and assembly language Had the advantage that the source code was

available

In 1991, in Helsinki, Linus Torvalds; secondyear student of Computer Science began aproject based on MINIX that later became theLinux kernel


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The early Linux project (Freax)

Was initially a terminal emulator, which wasused to access the large UNIX servers of theHelsinki university.

Written as OS independent and for a PC withan 80386 processor.

Used GCC for compiling

The Linux Logo (TUX) >>


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In August 25, 1991 the historic post was

sent to the MINIX news group by Linus,regarding his project. Linux version 0.01 was released by mid of

September 1991. The development gathered momentum

really fast.

By December 1991, came version 0.10.


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The GNU/Linux Time line

1992: The Linux kernel is relicensed underthe GNU GPL. 1993:

Over 100 developers work on the Linux kernel.With their assistance the kernel is adapted tothe GNU environment

The oldest currently existing Linux distribution,Slackware, is released for the first time.

The Debian project is established. Today it isthe largest community distribution.


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1994: In March, Torvalds judges all components of the

kernel to be fully matured: he releases version1.0 of Linux.

The XFree86 project contributes a graphic userinterface (GUI).

Red Hat and SUSE publish version 1.0 of theirLinux distributions.

1995: Linux is ported to the DEC Alpha and to the Sun

SPARC.Over the following years it is ported toan ever greater number of platforms.


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1996: Version 2.0 of the Linux kernel is released. The

kernel can now serve several processors at thesame time, and thereby becomes a seriousalternative for many companies.

1998: Many major companies such as IBM, Compaq

and Oracle announce their support for Linux.

A group of programmers begins developing thegraphic user interface KDE, which dependedon the then proprietary Qt toolkit.


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1999: A group of developers begin work on the

graphic environment GNOME, which shouldbecome a free replacement for KDE.

During the year IBM announces an extensive

project for the support of Linux. 2004:

The XFree86 team splits up and joins with theexisting X Window standards body to form theX.Org Foundation, which results in asubstantially faster development of the XWindow Server for Linux.


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The detailed time line can be obtained from

http://lwn.net/Articles/Timeline200 X / Replace X by 2 to 8

Older Time lines

2001: http://lwn.net/2001/features/Timeline/ 2000: http://lwn.net/2000/features/Timeline/ 1999: http://lwn.net/1999/features/Timeline/

1998: http://lwn.net/1999/features/1998timeline/


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GNU/Linux Distros

Since GNU and Linux are two separateprojects, companies and communitiescombined these with few other softwares,

and made packages, which could work as acomplete Operating System Slackware, RedHat, etc were among the

first GNU/Linux distributions(Distros) Today, 1000's of GNU/Linux distros are

available


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Community Backed

Debian Fedora Puppy

Commercially Backed RedHat Suse

Ubuntu


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GNU/Linux Architecture Similar to the UNIX structure Entirely different from UNIX code


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GNU/Linux

Architecture


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GNU/Linux


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Booting

Boot Loaders: GRUB LILO


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Ownership of Files and Processes

Each file has an owner and group owner Owner has all privilages over the file and

can set the privilages for other users

GNU/Linux keeps tracks of files using UID'sand GID's


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File Permissions

Uses traditional UNIX model CHMOD

0 : --- 1 : --X 2 : -W- 3 : -WX 4 : R--

5 : R-W 6 : RW- 7 : RWX


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Processes

The Kernel's internal data structures recordvarious pieces of information about eachprocess

Address space map Current status Priority

Resources used

Files and ports used Owner


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Kernel assigns a unique ID number to eachprocess PID Assignesd in the order in which processes are

created System processes have low PID


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Process is created by a fork system call as

in UNIX Creates a copy of process with unique PID Uses exec system calls to begin execution of

new process Clone Calls set of processes that share

memory, I/O or both. INIT Automatically started process during

booting; PID=1 INIT executes startup scripts


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INIT

Represents a particular complement ofservices that the system should be running O completely Shutdown 1 Single User Mode 2 to 5 Multiuser Levels 6 Reboot


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Process States

Four execution states Running Process can be executed Sleeping Waiting for some resource

Zombie Trying to die Stopped Suspended (Not allowed to execute)


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Desktop Environments Variety of desktop environments are

available

KDE GNOME XFCE LXDE


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KDE


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GNOME


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Desktop Managers There were many recent advancements in

the GNU/Linux Desktop managers Compiz OpenBox


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GNU HURD The original Kernel project for GNU A Micro Kernel

Initially decided to use Mach micro kernel In 2004, decided to port to L4

GNU HURD Logo >>


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According to the Debian documentationthere are 24 servers (18 core servers and 6file system servers)

Core servers auth (authentication server) crash (crash server) exec (execution server) Fifo (FIFO translator) new-fifo (new FIFO server) firmlink (the firmlink translator)


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fwd (forward server) hostmux (host multiplexer server) ifsock (server for sockets interface) init (init server) magic (magic server) Null (null server) pfinet (pfinet server) Pflocal (pflocal server) proc (process server) symlink (symbolic link translator)


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term (terminal server) usermux (user multiplexer server)

Filesystem servers The ext2fs server "ext2fs" The iso filesystem server "isofs" The nfs server "nfs" The ufs server "ufs" The ftp filesystem translator "ftpfs" "storeio"; The storage translator


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