START Track II - Introduction to Linux

Table of Contents

• What is Linux?

• Brief Introduction to Linux
  • The Boot Sequence
  • Command-Line Interface
  • Graphical User Interface
  • Login
  • Fundamental Applications

• Linux Architecture

• The Kernel
  • Modules
  • Re-compiling

• Filesystem Information
  • Hierarchical
  • Components
    • file
    • directory
    • links
    • special files
    • inodes
  • Everything is a file
  • Mounts (disk, NFS)
  • Filesystem Types
  • Common UNIX Directory Structure

• Users and Groups
  • User == uid
  • Group == gid
  • authentication
  • /etc/passwd
  • /etc/group
  • Permissions

• Distributions

• Comparison to Windows
  • Registry
  • Services
  • Software Packaging
  • yum
  • User Applications

• A Brief history of Time...

• Resources
  • LSU Linux Resources
  • Linux Documentation
  • Other Important Resources

What is Linux?

Operating System

• kernel
• modules (drivers)
• filesystem(s)
• CLI and/or GUI
• GNU
• collection of utilities, applications, and services

Flexible System

• Distributions
• Multi-platform / Multi-architecture
• Desktop / Server

Why?

• It's free (most distributions)
• It's mature (14 years old, will do whatever you want, and is stable)
• It's secure (and is maintainable)
• It's efficient (extend life of hardware)
• It's growing in popularity (28% of server market, 3% of desktop)
• Apache has 69% of the web servers on the Internet (majority on Linux).
• It's interoperable (among other major OSs)
• Many choices of distributions, applications, and services

Brief Introduction to Linux

The Boot Sequence

Restart the Windows system and choose Fedora Core 3 Linux instead of the default Windows

After the BIOS checks the hardware, it reads the Master Boot Record (MBR) from the first Hard Drive (HD) in the machine. GRUB, the GRand Unified Bootloader, is the preferred boot loader for Red Hat Linux. LILO, the LInux LOader, was the dominant predecessor to GRUB. When booting, the first thing you see after the BIOS is done is the GRUB menu. The menu allows you to select which operating system, Windows or Linux including kernel versions (SMP, UP, hand-compiled, etc.), to load. GRUB then initially loads and transfers control to the operating system.

For Linux, GRUB then loads the kernel which immediately starts detecting hardware and loading drivers. As soon as the kernel is fully loaded and initialized it starts the init process which displays the Welcome to Fedora Core message. Newer versions of init allow you to press "I" to enter an interactive mode, letting you choose which services to start or not start, similar to jumping into Extension Manager on a Macintosh system, or pressing F5 at boot on a DOS/Windows system.

Shortly after the welcome message, the screen will clear and Fedora will go into a GUI display. It will show a progress bar as the system boots. You can click the "details" button to have the GUI boot display show the startup progression. As each service is started, its name is echoed on the left of the screen. If the service starts successfully, a message [  OK  ] appears on the right. If the service failed to start successfully, a message [FAILED] appears on the right.

Fedora Core 3 can be set to use the traditional command line boot (not boot graphically) by editing /boot/grub/grub.conf and removing the characters rhgb from the grub boot stanza.

Once all of the services have loaded, indicating init has finished, the login prompt appears.

Command-Line Interface

Like the family of UNIX ^*-like operating systems before it, the primary interface to Linux is the command-line. The command-line is still the most powerful and direct way to interact with the system. Shells are how command-line interfaces are implemented in Linux. Each shell has varying capabilities and features and the user should choose the shell that best suits their needs. The shell is simply an application running on top of the kernel and provides a powerful interface to the system.

Graphical User Interface

Graphics were not a native part of the original UNIX environment. The X-Window system is a client / server based protocol for displaying graphics. The system where the graphics are viewed runs an X-Window server. The system where the graphics are generated runs an X-Window client. They can be the same machine (just like a traditional Windows environment) or they can be two different systems an Internet apart (as implemented by Remote Desktop in Windows). Clients are typically applications, such as a web browser like Firefox, that make a request to have things drawn on the screen.

The X-Window system grew out of the Athena project at MIT.

Most commercial UNIXes provide proprietary X-Window servers for their version of UNIX. The free UNIX world has concentrated on XFree86 as the primary X-Window server, though the "86" refers to the Intel x86 architecture, XFree86 has been ported to numerous architectures. In 2004, the XFree86 project changed their license to be more restrictive. As a result, many developers left XFree86 and joined X.org, using the last truly "free" XFree86 release as a starting point. Since that time, X.org has replaced XFree86 as the de facto standard for X Windows on most Linux distributions.

Besides the X-Window server, the X-Window protocol requires a window manager to display the windows. The window manager controls the overall look and feel of the windowing environment (minimize, maximize, close, scroll-bars, borders, colors, title bars, etc.). The two currently dominant window managers in the free UNIX world are KDE and GNOME (but there are dozens of others to choose from like fluxbox, fvwm, etc.). KDE was developed by an independent group of programmers and was inspired by the commercial CDE environment. GNOME development was started under a free license by Red Hat. Each window manager or desktop can be made to look differently depending upon which theme is chosen.

Red Hat, as of their v8.0 release, has taken a giant step forward, according to some people. They have developed a common, consistant, interface using a theme called Blue Curve. Regardless of whether the user picks GNOME or KDE, the GUI looks 95% identical. Fedora has continued to build on Red Hat's Blue Curve development.

Running an X-Window server and window manager on a machine provides a familiar graphical interface. As is typical, in the free UNIX world the user has a choice.

The computer mouse was invented in 1968 by Douglas Englebart while at Stanford University.

Login

The login process authenticates the user and is the mechanism allowing them to interact with the system, if authentication is successful. The user's login ID will subsequently be used to determine authorization later on.

The initial boot screen in Fedora Core 3 is now a GUI. The login screen allows users to chose which style of desktop they want, provides for the ability to restart or shutdown the computer, and allows users to change their default language.

In order to interact with the machine users must have a valid ID and password. As you will learn, this ID and password may or may not be stored on the local machine. The name space (users and groups) can be maintained on another server somewhere on the network.

Login as student

Fundamental Applications

The following applications provide a basic interface to the system. Since they will be used frequently in this class, we take time to introduce them now.

Console

Since the command-line interface (CLI) is the primary interface to a UNIX system, having access to the command-line while in a GUI is critical. A console application serves this purpose, similar to command.com or cmd.exe in Windows. Each desktop manager typically has its own version of a console application. Under GNOME the application is gnome-terminal and under KDE the application is konsole.

Open konsole by clicking on the Red Hat icon | System Tools | Terminal

Other things you can do:
• resize the window: the default is 80x24
• right-click | Settings: font, schemas, configure konsole
• tabs or multiple windows

Konqueror

Konqueror started as a browser application, but has grown in scope (like Internet Explorer in Windows) to include many other functions such as file management, application framework, and general I/O application.

Open konqueror by clicking the Red Hat icon and then clicking the "Home" icon

Other things you can do:
• Profiles: web browser, filemanager, etc.
• As an application framework: console
• General I/O: Audio CD, network access
• Tabs: multiple windows in one

Other Applications

The above applications will be talked about more later on.

* “UNIX is a registered trademark of The Open Group in the United States and other countries.”

Linux Architecture

Linus Torvalds set out to write his own operating system as a result of his dissatisfaction with Minix and its creator, Andy Tanenbaum.

In 1987 Andrew S. Tanenbaum -- a professor in Amsterdam, the Netherlands -- created MINIX as a teaching aid for his Operating Systems class.

Linus soon realized that the project was a huge undertaking so he decided to start by writing a kernel, utilizing the tools being developed by the GNU project (shells, compilers, editors, etc.).

In 1984 and 1985, Richard M. Stallman started GNU and founded the Free Software Foundation.

As Linus made early progess, he made copies of Linux available to other people via the Internet. Suggestions for improvement and fixes for bugs started flooding in and full Internet collaboration on the kernel project started.

Today, Linux is composed of a kernel and other supporting applications layered around it. The development of Linux would not have been possible without the software provided by the GNU project and developers from all over the world and the use of the Internet.

Kernel

The kernel is at the heart of the operating system. It controls all of the hardware in the machine and provides coordinated access to that hardware. It starts and stops processes (programs), allocates memory to programs, manages virtual memory (swap), associates drivers with hardware, controls interrupts (hardware and software), provides TCP/IP network capabilities, and provides a multi-tasking environment by cycling through all running applications.

Because of its modularity and open source nature, anybody can add functionality to the kernel. However, Linus has final authority over what is officially added to a kernel release. The "official" kernel can be found at http://www.kernel.org/.

Historically, kernels were released in "stable" and "development" versions. Kernel versions were numbered so that the second part (between the first and second decimal point) determines if the kernel is stable or development. Stable versions were always even numbered: 2.0.7-3, 2.2.12, and 2.4.9-13 are all stable kernels. Development versions were always odd numbered: 2.1.4, 2.3.5-2, and 2.5.1 are all development kernels. After freezing enhancements and bug fixes to a stable kernel, a new development kernel tree starts. When a development tree becomes stable enough, it gets renumbered as a new stable release.

A final benefit of Linus' open source, modular kernel is the user's ability to remove or include only the parts of the kernel they want or need. This has resulted in full blown router engines and firewalls that fit on a floppy disk. Additionally, this flexibility has allowed for the creation of the popular and prolific "Live CDs" and DVDs which allow you to boot your computer to run Linux without touching your hard-drive. Also, as a system administrator for a server, you can fully optimize the kernel code for what your server does.

Example vendors with Linux-based products
• Cyclades console/power servers
• ImageStream Routers

Modules

The Linux kernel includes device drivers allowing it to communicate with various hardware and virtual devices. Initially all drivers were built into the kernel. Modern kernels now support the dynamic loading and unloading of device drivers by the use of modules. This is similar to Windows but significantly different.

Insert a floppy disk and then mount it in a console window

$ /sbin/lsmod
$ mount /media/floppy
$ /sbin/lsmod

Notice the addition of the fat and vfat modules from before and after the mount command. The kernel knew it needed the device driver and dynamically added it to the running system.

Recompiling

Besides device drivers, the Linux kernel may contain various other functionality. The administrator of a system can choose to have these components either be an integral part of the kernel, loadable as a module, or excluded entirely. The process of selecting these components and regenerating a new kernel and / or modules is called recompiling the kernel, translating the human readable source code into machine understandable code. Invoking (running) a newly compiled kernel is one of the few times a Linux system needs to be rebooted.

Filesystem Information

Hierarchical

UNIX uses a true hierarchical filesystem, which is very different from the Windows structure. The UNIX filesystem starts at a single point: / (pronounced "root" [not to be confused with the root user or /root, the root user's home directory]).

Components

The UNIX filesystem is comprised of several parts:

file

Files contain data, either for users or the system. The data can be text or binary.

directory

A directory is a collection of files, like a folder in Windows.

links

Links are pointers to existing files or directories, similar to shorcuts in Windows.

special file

Special files include:
• sockets
• pipes
• character
• block
These special files are used by the kernel and running applications to control the flow of data in the system.

i-nodes

i-nodes contain all of the metadata about any of the above components such as the date and time they were created, who created them, when they were accessed, their size, where they are stored, etc.

Everything is a file

One of the most difficult thing to grasp about the UNIX filesystem is that everything in UNIX is treated as a file. EVERYTHING! This includes directories, special files, partitions, disk drives, mice, serial ports, printers, displays, network interfaces, etc. Everything!

Open the Konqueror window and navigate to the /dev directory

Mounts (disk, NFS)

The UNIX filesystem is analogous to a tree. The root, /, is the root of the hypothetical tree and directories are the branches. Real trees can have new branches grafted onto them. Similarly, the UNIX filesystem can have other filesystems grafted onto them. As such, the UNIX filesystem can be comprised of many different filesystems.

The mount command is used to perform the grafting or to show existing grafts.

In the console window, type mount to see a list of currently mounted (grafted) filesystems. Notice the /media/floppy item you mounted (grafted) earlier.

Even if several hard disks are in a system, all access to the disks will be through /. This is unlike the Windows world where separate disks/partitions are accessed via different drive letters (C:, D:, etc.).

Common UNIX Directory Structure

The UNIX filesystem is traditionally divided into a number of common directories. The series of directories, seperated by a slash ("/") and often ending with a file, is called a path. Each directory path has a specific function. Below is a table listing some of the common directories and their normal use:

Path	Windows Equivalent	Description
/	C:	The start of the filesystem (or main drive in Windows)
/home	My Documents or Profiles or D:	User's private files
/usr or /usr/local	Program Files	Installed software
/dev	Windows or Windows\System	Device drivers
/etc	The Registry or .ini files	Application and operating system configuration information
/tmp	Windows\Temp	Temporary system files
/bin or /sbin	Windows	System executable files
/mnt or /media	D:, E: or next drive letter	Where removable media, like floppys, CDs, DVDs, USB, SD, Flash, and the like are mounted

Open the Konqueror window and navigate to the /etc/sysconfig/network-scripts/ifcfg-eth0 file

Filesystem Types

Linux systems can access many different physical filesystem types. Recall that Windows can use either FAT, FAT32, or NTFS. The default physical filesystem under Red Hat Linux is ext2 or the newer ext3. Additionally, Linux can access many different physical filesystems.

It is important to note that of the many filesystems Linux supports, the Microsoft NTFS system is among them. Currently Linux has the ability to read NTFS filesystems. While there is a project to enable Linux systems to write to NTFS, it is currently unreliable and can cause corruption of the filesystem. Like other modern operating systems, Linux can access remote filesystems across the network. Windows calls this "Sharing". UNIX calls it NFS (Network File System). Similar to Windows, which can both serve and access Shares, Linux using NFS can export and mount filesystems. Samba is a software project to allow Linux (and other UNIX-like OSes) to mount and export filesystems the same way a Windows system "shares" directories.

Command-line Primer

The following are some of the more frequently used filesystem commands:

Command	Description	DOS/Windows Equivalent
awk	File processing and report generating	N/A
cat	Show contents of a file	type or double-clicking a file
cd	Change directory	cd or double-clicking a folder
cp	Copy a file	copy or dragging a file
file	Determine file type	file extension or right-click properties
find	Find a file	Windows Explorer Find
grep	Find lines in a file	N/A
ln	Link a file to another file	Create Shortcut
ls	Display files in a directory	dir or Windows Explorer
mkdir	Create a directory	mkdir or creating a folder
more	Display a file one page at a time	more
mv	Move or rename a file	rename or dragging a file
rm	Remove a file	delete or deleting a file
rmdir	Remove a (empty) directory	rmdir or deleting a folder
sed	Stream editor	N/A
vi	Edit a file	edit or notepad
wc	Count words, lines and characters in a file	N/A

Users and Groups

In Linux a user is identified by their username. Linux usernames are similar to Windows logon IDs. Linux maintains a list of users, called a name space, either locally on each individual machine or across the network via NIS for a group of machines.

User == uid

Each user on a Linux machine has a unique username that corresponds to a unique uid. The uid is a numeric value used to determine if the user is authorized to perform a particular task. It is important to note that the Linux operating system is concerned only with the numeric value of the uid and not the text that describes the user's name.

Group == gid

Groups are also associated with unique numbers called gids. Users may belong to more than one group, although they can be associated with only one group at a time. Groups may have zero, one, or more members. Like uids, the Linux operating system is concerned only with the numeric value of the gid and not the textual name of the group.

Authentication

Each time a user tries to login, Linux attempts to authenticate that user against a name space. The login process prompts for a username and, usually, a password. Linux then encrypts the entered password and checks to see if the encrypted text matches the stored version of the user's encrypted password. If there is a match, the user is authenticated; if not, the user is denied access.

/etc/passwd

Linux keeps a table of information about each user in the file /etc/password. Each line of this file represents a different user and has seven different fields:
1. username
2. encrypted password
3. uid
4. gid
5. identification
6. path to home directory
7. initial program

Look at the password file in a console window

$ cat /etc/passwd

/etc/group

Linuux maintains a list of groups as a table in the file /etc/group. This file has three fields:
1. group name
2. gid
3. list of usernames

In the Konqueror window navigate to the /etc/group file and open it

Permissions

Since Linux treats everything as a file, learning about file permisions is very important. Linux allows access to a file based upon affiliation as defined by user, group, and other. The possible permissions for each affiliation are read (r), write (w), and execute (x). Linux actually uses one bit to indicate these three permissions for each of the three affiliations.

List the password file in a console window

$ ls -l /etc/passwd

Your output should look similar to this:

-rw-r--r--    1 root     root         1755 Mar 10 13:48 /etc/passwd

The first dash is a flag specifying the type of file. The next three characters are the permissions for the user who owns the file. The next three characters are the permissions for the group associated with the file. The final three characters are the permissions for any user who is not the owner of the file nor belongs to the group associated with the file.

Each of the permissions has a different meaning depending on whether it is set for a file or a directory:

Type	r	w	x
File	Can read the file	Can change the contents or delete the file	Can execute the file
Directory	Can see a listing of files in the directory	Can create new files in the directory or delete files from the directory	Can change into that directory

Distributions

The kernel is the basis of a Linux system. Fairly early in the evolution of Linux, people other than Linus started putting the kernel together with various software packages. The different combinations of kernel and software packages became known as a distribution. All of the distributions start with one of the Linux kernels and then combine various other software to produce a usable system.

This early development resulted in a large number of Linux distributions being created. Suddenly, one version of Linux was not required to be everything to everyone, unlike with Windows. This flexibility allowed Linux to grow and prosper. Here is Red Hat's own description of their distribution, from the v6.2 "Getting Started Guide."

Early distributions included (but weren't limited to) Slackware, Yggdrasil, and Debian. Even Red Hat has a long history of over 10 years. The primary distributions in the U.S. today are Fedora, which branched from Red Hat, and the venerable Red Hat. The primary distribution in Europe today is SUSE, which was recently purchased by Novell. Other major distributions include (but again aren't limited to) Mandrake (which is based on Red Hat), Gentoo (source code based), YellowDog (for PPCs), and both Debian and Slackware still survive today. Visit Distro Watch for a nearly complete list of Linux distributions.

Another current trend is putting a Linux system on a CD. This approach has the benefit of not destroying data on the systems hard drive and allows users to experiment with Linux without modifying their current installations. One implication is that you can boot a machine and have a working system (from the CD) that can help you recover or analyze data on the local hard drive. The primary Linux-on-CD distribution today is Knoppix.

It is important to note that the kernel is completely seperate from any distribution. Kernel development and releases continue on their own schedule. When a new kernel is released, distributions take time to get their configuration and tools working with the new kernel (by adding and removing code to and from the kernel).

Even though most (usually all) of the software in a distribution of software is free (money-wise), distributors still sell Linux. Purchasing Linux usually provides you with printed manuals (books), installtion support, and sometimes commercial software. However, almost every distribution allows you to download a CD ISO image.

It should be noted that there are three major Windows "clones," namely Lycoris, Lindows, and Xandros. Their goal is to create a Linux system that looks and acts just like a Windows system.

Comparison to Windows

The combination of the Linux kernel, GNU (and other) tools, and a modern X-Window server with GNOME or KDE provides an experience similar to today's Windows systems. Many Windows-like capabilities have been replicated in the modern Linux/X-Window environment like desktop icons, file browsing, drag-and-drop, GUI configuration tools, etc.

Registry

While Windows maintains a binary "Registry" to hold system and installed software settings, Linux puts everything in files, most of which are text. As shown in our table above, the /etc directory tree in Linux contains most of the files to configure your system and installed software.

As an example, to change the DNS servers on a Windows machine you have to get to the Network Control Panel applet and navigate through several panels, make the change, and (depending on your Windows version) reboot the machine. In Red Hat, all you have to do is edit the /etc/resolv.conf file.

Use Konqueror to edit the /etc/resolv.conf file

Services

Older Windows v9x use the System Tray to emulate "services" running on the system. Windows NT and above actually implement true services which can be controlled using Server Manager. Red Hat controls services via scripts found in /etc/rc.d/init.d/ and automatically starts or stops these services based on entries in the /etc/rc.d/rcx.d/ directories.

Use Konqueror to navigate to the /etc/rc.d/rc3.d/ directory

Software Packaging

Windows applications typically use a consistant install program like "Wise" or "InstallShield" so that most software installations look and feel the same.

Red Hat Linux, as well as several others, use RPM, the Red Hat Package Manager. Software on these systems is bundled in a "package." RPM refers to both the package management program and to the packages. A package includes all of the binary data for the software, rules detailing prerequisite software, and possibly scripts to be executed before, during, and after installation. RPM, the software application, is all that is needed for managing the installation, updating, deletion and querying of packages.

RPM packages come in either source or binary form. Binary packages are architecture-specific (i.e. Intel uses i386, i486, i586, and i686; PowerPC uses ppc, SPARC uses sparc, etc.) and can only be installed on the appropriate hardware. Software packages include the source code, possibly some patches, and a specification (.spec) file detailing how to build the software, install, and possibly even configure it. The package manger command is rpm, and it sports a wide array of features.

Here is a table of commonly used rpm commands and what they do:

Command	Description
rpm -qa	List all installed packages
rpm -qi package	Show information about an installed package
rpm -qil package	Show information about an installed package including all files in the package
rpm -qip package	Show information about an uninstalled package
rpm -qilp package	Show information about an uninstalled package including all files in the package
rpm -qf file	Determine which installed package a file belongs to
rpm -Uvh package	Install or upgrade a package
rpm -Fvh package	Update an installed package (freshen)
rpm -e package	Uninstall a package
rpm --verify package	Verify the integrity of an installed package
rpm --help	Get help on rpm (there are many more options available)

yum

RPM is an excellent system for creating, installing, updating and deleting software packages. However, it has a multitude of options (see chart above for just a few). Most users do not need all the power and features of RPM. In fact, RPM can be a little bit overwhelming. The good news is that you will probably never have to use RPM. The Yellow Dog Linux distribution developed yup, the Yellow Dog Updater, to simplify the task of updating RPM-based systems. Then, a systems administrator at Duke University who heavily used yup but wanted to improve it, re-wrote yup and called it yum, Yellow Dog Updater, modified.

yum was originally designed as a simple front-end to the --update features of rpm. yum uses RPM commands behind the scenes and has grown to include the ability to install, update, remove, and report on RPM packages. One of the great things about yum is that it actually understands the pre-requisite information in RPM package. If you ask yum to install a package, it will discover all prerequisites and install all needed parts at one time without any additional help. Much easier than the old way of tracking down RPM pre-requisites by-hand. yum also supports a very simple way of querying RPM repositories to discover new software and updates.

Here are a few yum command examples:

Command	Description
yum	display brief help
yum check-update	update headers and display any updates the current system needs
yum update	check for updates and apply them interactively
yum -y update	check for updates and apply them with
yum update <package>	check for updates and upgrade the specified package(s) only
yum info	similar output to a rpm -qai
yum info <package>	information about a specific package
yum list	lists all available packages
yum list <package>	list individual package(s)
yum list installed	list all installed packages
yum list available	list all packages not installed
yum list update	list all packages that need to be upgraded
yum list extras	list all installed packages that are not available from any of the defined yum resources (defined in the /etc/yum.conf file)
yum clean	delete any rpms in the yum cache and remove any unneeded headers
yum install <package>	install the package
yum remove <package>	delete the package
yum provides <file>	find out what package provides a particuar file
yum search <string>	searches for packages containing the string in their name or header info

Check for new updates

$ yum check-update

To demonstrate software installation, we are going to install a package called Neverball. This package is not part of the Fedora Core 3 software distribution. It has a prerequisite that is also not part of the default distribution. Don't worry. yum makes this easy. We are going to replace our /etc/yum.conf with a new one that tells yum to look in the special START II repository.

Replace /etc/yum.conf

$ su -
# cd /etc
# mv yum.conf yum.conf.org
# wget http://fedora.lsu.edu/dist/start/fc3/yum.conf
# vim -d yum.conf yum.conf.org
:q
:q

Install the neverball game

# yum install neverball

After a Windows installation, the first thing you need to do is update the system with security patches. Similarly, after a Linux OS installation you need to apply critical updates. With yum installed and configured, the process to update a Linux system is the following:

# yum -y update

Please visit the local yum web page for more information about yum and using LSU local mirrors.

User Applications

The Free Open Source Software (FOSS) community has produced software to match almost every application. Following is a very limited comparison of FOSS and commercial software. Items on the same line are not meant to be a direct comparison.

Category	Commercial Example(s)	FOSS Example(s)
Productivity	Microsoft Office WordPerfect SmartSuite StarOffice	OpenOffice AbiWord Gnumeric
Graphics	Photoshop	Gimp
Document Layout	Acrobat PageMaker Quark	xpdf Scribus
Web Browsing	Internet Explorer	Mozilla Firebird Lynx Links
Instant Messaging	MSN ICQ AIM Yahoo! Trillian	GAIM Silc
Music and Video Players	Windows Media Player QuickTime WinAmp	Xine XMMS MPlayer Noatun VLC
Video Authoring	Premiere AVID	Cinelerra kino
CAD	AutoCAD	qcad
Programming	Microsoft Visual C/C++/Basic Intel Compilers Portland Group	GCC Eclipse
Web Server	IIS	Apache
Web Applications	ASP	PHP Perl
Database	DB2 Oracle SQL	MySQL PostgreSQL
Math	Matlab	Octave

It should be noted that many of the packages above can also run on non-Linux operating systems. Additionally, some of the FOSS applications listed above do not have a commercial equivalent.

Open various applications

A Brief History of Time...

UNIX

UNICS (UNiplexed Information and Computing Service) was created at AT&T Bell Laboratories in the fall of 1969 by Ken Thompson and a few other researchers after failed attempts at working on the MULTICS project. Their work was the result of trying to create a multi-user time-sharing operating system. They started licensing their code to universities in 1974.

“...the number of UNIX installations has grown to 10, with more expected...” - Dennis Ritchie and Ken Thompson, June 1972

While on sabbatical in 1978, Ken Thompson helped student Bill Joy write the Berkeley Software Distribution (BSD). AT&T's UNIX became a stable commercial product while BSD's became a research project and teaching tool. This split between AT&T UNIX and BSD UNIX remains today. However, most commercial and free UNIXes are a blend of both.

It should be pointed out that the first operating system that Microsoft sold in August of 1980 was Xenix their UNIX-like OS that ran on both Intel and Motorola processors. Microsoft did not sell their first version of DOS until 1981.

Free UNIX-like OSes

In 1984 and 1985, Richard M. Stallman started the GNU project and founded the Free Software Foundation. His goal was to create a totally free (libris) UNIX-like operating system. Though many supporting tools were written quickly, the kernel, called the Hurd, was many years in coming. In 1985 Carnegie Mellon created the MACH kernel based on a micro-kernel architecture.

In 1987 Andrew S. Tanenbaum, a professor in Amsterdam, the Netherlands, created MINIX as a teaching aid for his Operating Systems class. This was one of the first complete implementations of a "free" UNIX-like OS, although you had to buy Dr. Tanenbaum's book to get it.

Starting in the early 1990's there were several projects that branched from BSD. The NetBSD and FreeBSD projects both started in 1993. In 1995 a disgruntled NetBSD contributor left and founded the OpenBSD project.

History of GNU/Linux

As part of his schooling at a university in Helsinki, Finland, Linus Torvalds started to write a new filesystem for MINIX. In 1991, after several disputes with Dr. Tanenbaum, Linus decided to write his own operating system. Over time, with the help of others on the Internet, Linus got parts of Stallman's GNU software (shells, compilers, etc.) working with his kernel.

From: torvalds@klaava.Helsinki.FI (Linus Benedict Torvalds)
Newsgroups: comp.os.minix
Subject: Free minix-like kernel sources for 386-AT
Keywords: 386, preliminary version
Message-ID: <1991Oct5.054106.4647@klaava.Helsinki.FI>
Date: 5 Oct 91 05:41:06 GMT
Organization: University of Helsinki
Lines: 55

Do you pine for the nice days of minix-1.1, when men were men and wrote
their own device drivers? Are you without a nice project and just dying
to cut your teeth on a OS you can try to modify for your needs? Are you
finding it frustrating when everything works on minix? No more all-
nighters to get a nifty program working? Then this post might be just
for you :-)

As I mentioned a month(?) ago, I'm working on a free version of a
minix-lookalike for AT-386 computers.  It has finally reached the stage
where it's even usable (though may not be depending on what you want),
and I am willing to put out the sources for wider distribution.  It is
just version 0.02 (+1 (very small) patch already), but I've successfully
run bash/gcc/gnu-make/gnu-sed/compress etc under it. 

Sources for this pet project of mine can be found at nic.funet.fi
(128.214.6.100) in the directory /pub/OS/Linux.  The directory also
contains some README-file and a couple of binaries to work under linux
(bash, update and gcc, what more can you ask for :-).  Full kernel
source is provided, as no minix code has been used.  Library sources are
only partially free, so that cannot be distributed currently.  The
system is able to compile "as-is" and has been known to work.  Heh. 
Sources to the binaries (bash and gcc) can be found at the same place in
/pub/gnu. 

ALERT! WARNING! NOTE! These sources still need minix-386 to be compiled
(and gcc-1.40, possibly 1.37.1, haven't tested), and you need minix to
set it up if you want to run it, so it is not yet a standalone system
for those of you without minix. I'm working on it. You also need to be
something of a hacker to set it up (?), so for those hoping for an
alternative to minix-386, please ignore me. It is currently meant for
hackers interested in operating systems and 386's with access to minix.

The system needs an AT-compatible harddisk (IDE is fine) and EGA/VGA. If
you are still interested, please ftp the README/RELNOTES, and/or mail me
for additional info.

I can (well, almost) hear you asking yourselves "why?".  Hurd will be
out in a year (or two, or next month, who knows), and I've already got
minix.  This is a program for hackers by a hacker.  I've enjouyed doing
it, and somebody might enjoy looking at it and even modifying it for
their own needs.  It is still small enough to understand, use and
modify, and I'm looking forward to any comments you might have. 

I'm also interested in hearing from anybody who has written any of the
utilities/library functions for minix. If your efforts are freely
distributable (under copyright or even public domain), I'd like to hear
from you, so I can add them to the system. I'm using Earl Chews estdio
right now (thanks for a nice and working system Earl), and similar works
will be very wellcome. Your (C)'s will of course be left intact. Drop me
a line if you are willing to let me use your code.

		Linus

PS. to PHIL NELSON! I'm unable to get through to you, and keep getting
"forward error - strawberry unknown domain" or something.

In 1994 he released a v1.0 kernel and the associated GNU tools as the first widespread public GNU/Linux distribution. Unlike MACH, the Linux kernel is a monolithic or macrokernel where most of the functionality is implemented in the core of the operating system.

Resources

Many resources exist at LSU and across the Internet to make using GNU/Linux easier. Here are just a few.

LSU Linux Resources

LSU has a number of Linux resources available thanks to OCS, CCT and the Department of Mathematics. Here is a brief list:

• linux.lsu.edu - front page for various LSU Linux sites and information
• redhat.lsu.edu - RedHat's public distros prior to Fedora
• rhn.lsu.edu - RedHat Network, commercial release
• fedora.lsu.edu - current free RedHat release
• mandrake.lsu.edu - Mandrake distribution
• knoppix.lsu.edu - Knoppix CDs
• debian.math.lsu.edu - Debian distribution
• ldp.lsu.edu local copy of Linux Documentation Project

Linux Documentation

The Linux Documentation Project has been around a long time and is one of the most valuable resources around. This project includes many different documents that will ease the use of GNU/Linux. Here are a few examples:

• The HOWTOs - These are wonderful documents that explain how to do just about everything you could want.
• The Mini HOWTOs - These are smaller documents that often cover new topics or very simple concepts.
• The Unmaintained HOWTOs - These are older HowTos that no one is keeping current but they often have useful information.
• Redhat - Along with selling the dominant U. S. GNU/Linux distribution, they provide numerous guides, patches, and forums.

Fedora Links

• Basic Fedora Links
  • Fedora RedHat site - official Fedora site
  • LSU Fedora site - local Fedora support site
• Fedora News
  • Fedorazine
  • Fedora News
• Fedora Help
  • Fedora Wiki
  • Securing Fedora Article
  • Fedora Multimedia Installation HOWTO
• Additional Download Sites
  • Fedora Legacy - project to provide critical fixes for unsupported RedHat releases
  • livna - additional Fedora RPMs
  • Fresh RPMs - additional Fedora RPMs
  • Fedora Extras

Linux History

These links provide for a little history and more documentation on some distributions.

• History of Linux at Red Hat
• Wikipedia's Red Hat Linux entry
• Wikipedia's Gentoo Linux entry
• Fact-index's Linux Distribution entry
• Fact-index's Red Hat Linux entry
• Fact-index's Gentoo Linux entry
• Fact-index's Tux the Penguin entry

Other Important Resources

• Freshmeat - daily list of updated software and software repository
• rpmfind - source for rpms
• Security Focus
• SlashDot - news for geeks
• Source Forge - Open Source Software Repository

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The statements and opinions included in these pages are those of Brian D. Ropers-Huilman, Allen B. Gordon, Isaac W. Traxler, and Greg P. Brignac only. Any statements and opinions included in these pages are not those of Louisiana State University or the LSU Board of Supervisors.
© 1998-2005 Brian D. Ropers-Huilman, Allen B. Gordon, Isaac W. Traxler, and Greg P. Brignac

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Page last modified: Tuesday, 24 May, 2005 16:14:20.