If you are reading this you might be wondering what the hell is Linux. What is so great about it. Where can I get it. I hope to create a document to answer many newbie questions. Below I have created an image of the break down of the linux OS as I see it.



Linux or as it should be called GNU linux is made up of many parts. There are mainly 3 but I have included a 4th.

• Explanation of each group below
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• Linux - When you hear the term Linux, think Linux kernel. The Kernel was created by a now famous man Linus Trovalds. Linus's pronunciation of linux is lee-nucks. Much of the non kernel software is GNU. Other components come from many organizations, groups, and individuals. The name Linux sort of refers to a UNIX like operating system. This in a nutshell means it is an implementation of the POSIX specification.
  
  Now Linux is not UNIX. It is a free implementation of UNIX that cannot be called UNIX. UNIX is a registerd trademark of the Open Group. Although there is some confusion these days as to weather the SCO Group might own UNIX. Only time and a bunch of lawyers will tell.
  
  An operating system must conform to the Single Unix Specification (SUS) to be called UNIX. Linux dose not conform to SUS so it is not UNIX. GNU software has many moe features than SUS requires. The Open Group charges major money for SUS testing, and since Linux is free/open source... who will pay for this testing?
  
  Now here is a kicker. Some patched versions of VMS and Windows NT conform to SUS and therefore can be called UNIX. Many Govt. and DoD agencies require thier OS's to be POSIX compliant. Microsoft wants thier money sooo they comply. Yes guys that is a fact. Linux could probably pass the SUS testing without any problem. But no one has the money to get it to testing. Much less each companys version of it.
  
  Some info on the Linux Kernel. Linux Kernel began as Linus Trovalds personal project to run a UNIX like operating system on an i386 PC. He also wanted to improve on Andrew Tanenbaum's Minx. Version 0.02 was made public in the newsgroup comp.os.minix on October 5, 1991. It ran bash, gcc, gnu-make,gnu-sed, compress and some other applications. Sources were made available for general development.
  
  Linux was originaly writen for intel processors but now supports all intel i386, i486, Pentium-series, Cyrix and AMD clones, 68000, MIPS, PowerPC, PowerMac, SPARC, 64-bit CPU's to include Alpha, UltraSPARC, and Itanium. Not bad for a personel project. Not bad for free.
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• GNU - The GNU system comes from The Free Software Foundation founded by Richard M. Stallman in the 1980's. His main goal was to creat freely distributable UNIX tools. Richard M. Stallman and The Free Software Foundation belive software should be free from patents and commecial ownership.
  
  The GNU provides many UNIX commands and useful applications. Many GNU tools such as make , are much better than ther commercial counter parts. You will quickly find the GNU people love word play. The GNU replacement for the pager more has more functionality and is called less .
  
  Linux and the GNU were a perfect match in the early 1990's. The Linux kernel needed supporting software and the GNU needed a supporting Kernel.(It now has Hurd). Linux and the GNU together made a complete free UNIX-like operating system.
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• X - X or X windows is a powerful networked graphical environment. X was developed at MIT and is freely distributable. XFree86 is a complete implementation of X based on the X11R6 standard.
  
  Linux is most popular as a server. Now most servers do not require a graphics, as a mater of fact if you do not need them you want to not install them. Nothing like a resource heavy screen save to crash your server at just the right time. However X can provide some of the most sexy graphics you ever saw.
  
  see examples below
  
  http://thebucket.org/echo/gallery/albums/screenshots/noia_warm_kde.sized.png
  
  http://thebucket.org/echo/gallery/albums/screenshots/gimp_1_3.sized.png
  
  http://thebucket.org/echo/gallery/albums/screenshots/karamba.sized.png
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• Other - Many Unix software packages have now been ported to Linux. UNIX packages are often distributed in source form. Many server componets are generic UNIX software. Some software components are free implementation of commercial products. And some ore unique to Linux.

Added 01/31/2004 21:18
This is an old and slightly outdated link, but still tons of good info.

Good *nix distro's:
Linux distros
Slackware http://www.slackware.org/
FreeBSD http://www.freebsd.org/
OpenBSD http://www.openbsd.org/
Debian http://www.debian.org/
Gentoo http://www.gentoo.org/
RedHat http://www.redhat.org/
Mandrake http://www.mandrake.org/

Mandrake is a great introductory distro; I however prefer Slackware.

BSD distro's
BSDi http://www.bsdi.com
(at time of post currently off line..)
Free BSD http://www.freebsd.org
Open BSD http://www.openbsd.org
Net BSD http://www.netbsd.org

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*Edited by Sin_tax to give BSD distros as some may be intrested*
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Development and Support Principles

Development is world wide. Organizations, groups, or individuals control one or more software components. There is allways USENET newsgroup or mailing list for discussion, announcements, bug reports, questions and answers.

• Examples of each below
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• USENET
  comp.os.linux.advocacy
  comp.os.linux.advocacy
  comp.os.linux.development.apps
  comp.os.linux.development.system
  comp.os.linux.hardware
  comp.os.linux.networking
  comp.os.linux.setup
  comp.os.linux.x
  linux.dev.lugnuts
  linux.dev.mca
  linux.dev.mgr
  linux.dev.msdos
  linux.dev.net
  linux.dev.new-lists
  linux.dev.newbie
  linux.dev.normal
  linux.dev.nys
  linux.dev.oasg
  linux.dev.oi
  linux.dev.pkg
  linux.dev.ppp
  linux.dev.qag
  linux.dev.scsi
  linux.dev.serial
  linux.dev.seyon
  linux.dev.sound
  linux.dev.standards
  linux.dev.svgalib
  linux.dev.tape
  linux.dev.term
  linux.dev.uucp
  linux.dev.wabi
  linux.dev.word
  linux.dev.x11
  linux.fido.ifmail
  linux.free-widgets.announce
  linux.free-widgets.bugs
  linux.free-widgets.development
  linux.largesites
  linux.local.chicago
  linux.local.nova-scotia
  linux.local.silicon-valley
  linux.motif.clone
  linux.new-tty
  linux.news.groups
  linux.ports.alpha
  linux.ports.hp-pa
  linux.ports.powerpc
  linux.samba
  linux.samba.announce
  linux.sdk
  linux.sources.kernel
  linux.test
  linux.wine.users
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• Mailing lists
  http://oslab.snu.ac.kr/~djshin/linux/mail-list/subscribe.cgi?alge
  http://oslab.snu.ac.kr/~djshin/linux/mail-list/subscribe.cgi?axp-list
  http://oslab.snu.ac.kr/~djshin/linux/mail-list/subscribe.cgi?caldera-announce
  http://oslab.snu.ac.kr/~djshin/linux/mail-list/subscribe.cgi?caldera-app-users
  http://www.debian.org/MailingLists/subscribe
  http://www.redhat.com/mailing-lists/
  http://www.mandrakelinux.com/en/flists.php3
  http://www.linux.org/docs/lists.html
  http://www.linuxhq.com/lnxlists/subscribe.html
  http://www.arm.linux.org.uk/armlinux/mailinglists.php
  http://www.linux.org.uk/mailman/listinfo
  http://www.tux.org/lkml/#related-lists

Linux and the open source movement are sucessfull because people take pride in developing free software. It is quite often writen to the highest software engineering standards.

Linux components are not formally supported by thier originators. There is some third part support for some components. However, because this is open source(meaning you can see the code for each program) there is usally a rapid response to bugs and missing features. Usally faster than commercial products. You will find companies will support specific distributions.

Hardware Utilization

Linux can turn older machines into useful servers. Many network services have minimal CPU and memory requirements. You could even combine several low speed computers into 1 power cluster. Linux can run withou problems on a 32 mb computer if it is installed right. Some more modern distibutions may be difficult. Opperating systems such as windows will run poorly or not at all.

Linux also works well on high end computers. It can be installed on multiple processor machines. It can handle up to 64 Giga bytes of ram. And it can handle thousands of partions. Up to 16 Tera byts of storage.

From here out I will address servers as that is what linux is most used for today.

Linux Servers

The term Linux servers stirs many emotions and images for many people. Some think Red hat, Some think IBM, and the list goes on. Linux is a free open source alternative to commercial software out there. Then how good could it be right? Well it is the fastest growing server out there.

If popularity is any indication Linux is one kick ass OS to run your server on. Some Linux flavors have built whole sections of thier buisness on the fact thier Linux is a better more secure linux. See links below

http://www-1.ibm.com/servers/eserver/linux/home.html?c=serversintro&n=Linux2001&t=ad

http://www.suse.com/us/business/products/server/index.html

http://www.mandrakesoft.com/products/corporate-server

http://www.linuxvirtualserver.org/

http://servers.linux.com/

http://www.penguincomputing.com/store/altus.php?PHPSESSID=6742bd38acd685c794c70c40789d0493


But wait, I said Linux is free. Most all these links want you to pay. Yep. Linux it's self is free. Much of the applications/software that comes in a distribution is also free. However a vendor can create thier own applications and not release them under the GNU\'s GPL (Gnu Not Unix GENERAL PUBLIC LICENSE) . That means people can get paid writeing applications for Linux. If you read this far you probably think that is a good thing and it is.

Linux and anything else release under the GPL is free and you will never get in trouble burning copies. But you must license and pay for commercial software coded for the Linux OS(Well it is the right thing to do anyway.. ) :p

Moving back to the main topic. As you can see Linux servers are now prety much main stream. Now what is a server ? A server is a kind of servant. It fetches us info and sends it to us. There are various types of servers. Most people think of web servers when they hear the term " server ". However it takes a DNS server to make web names work. There is also a POP3 server for email. Of course there is an FTP server also. These are just a few different types of servers. Appache provides a Server suit released under the GPL that has many of these built into it.

Before we get too far into servers lets go over Linux installation.

Instalation Overview

A installation needs to be booted. Kinda like MS Windows. Usally this is done from a CD-ROM. Sometimes you will use a diskette when the distribution is loaded over a network. Linux MUST detect the hardware in use. That is to say

• It must find the distribution files by detecting the CD-ROM drive or network card
• Beable to find the hard drive to receive the Linux installation

The installation program may ask you for some info. In principle, this is not necessary because the installation can be automatic. It might ask for the following.

• User's prefered language
• Keyboard type
• Mouse type
• Time zone
• How the hard drive should be partitioned
• Which software packages are required
• The password for the "root" user (Super user or admin)
• Network configuration information
• And last, it may need to set up your graphics

The first 4 you should be able to do fairly easy. If not please see the newbie forum for help. Lets take a look at the partioning of a hard drive. It realy isn't that hard.


Disk Partitions

To better understand why to partion it helps to better understand the UNIX file structure. See the image I created below.

The Linux/UNIX file system looks like one large tree structure. The top of the tree is called "root". All computer geeks know the tree structures have thier root at the top right? Each directory in the structure can be a separate file system. File systems can be seamlessly mounted into the tree structure.

Making use of multiple file systems improves both security and performance. Heavily used directories can be on seperate disks to reduce thrashing. A good rule of thumb is one busy directory per physical disk. Also mount options can greatly improve system security. System programs can be read-only file systems to prevent tampering.

Things to consider when deciding on how to partion the disk.

• How much free disk space?
• How many physical disks?
• One big Linux file system or several smaller ones?
• A typical Linux install requires between about 300 MB to 3,000 MB of disk space
• How much swap space is required for memory?

Disk Geometry

Disk storage is divided into units called cylinders. This is an arbitrary unit defined by the drive electronics and the BIOS. BIOS can provide 2 different views of a disk.

1.) Large number of cylinders
2.) Fewer than 1,024 cylinders

** NOTE Never change this setting once the disk has data installed **

Bootable components of Linux must be in a partition that fits completely within the first 1,024 cylinders. A small first partion mounted as /boot solves this problem.


Here is a list of components of the Linux file system comonly separated.

• / - The root system can be small
• /boot - Contains the kernel and boot manager files and is very small
• /usr - contains most application software and may be read only
• /opt - can be used to hold optional application packages
• /var - contains spool areas, which can get very big
• /tmp - contains temporary storage, which can get very big
• /home - contains user home directories

I will cover more later. I plan to make an image for partions and explain the recomended swap size and explain how it came to be and why it is as useful as tits on a bull now.