General Information on installing Linux

There are numerous ways to use Linux with a computer. The most common method is to allocate part of your hard disk to Linux and put all the software you need on it. It's also possible to use Linux without touching your hard disk at all, either by getting the software from another computer on a network or by using a cd or dvd. When people talk of installing Linux though, they invariably mean using the hard disk to store all their required software.
To install Linux on your hard disk, you first need to be able to allocate a section of the hard disk to Linux. Thankfully all sorts of computer systems understand the methods of dividing hard disks so two or more operating systems (e.g. versions of Linux and /or Windows) can reside on just one hard disk. More details on dividing the hard disks are given in the next section. Once that is done, you need to get a startup/install disk. Just as you would use a startup disk to access windows in case of a crash, a Linux startup/install disk will boot your computer in the Linux OS, albeit a limited version of it. The startup disk also contains info on accessing the hardware it needs to complete the installation and the complete install system itself. Most Linux installations are done from either CD-ROM or DVD-ROM install disks.
If your computer is built from common hardware which is well supported by Linux, it is unlikely that you will have to do any configuration to make the hardware work in your computer. It is not uncommon however to find that your computer has some hardware which does not work (well or at all) with Linux, the most common problem being with Modems which are an eternal source of frustration for new Linux users. You can use the internet site at http://www.linmodems.org/ to try and determine if your modem should work with Linux, or if there are any special steps required to make it work. Generally most other problems experienced with hardware when installing Linux are related to very new models or new types of hardware which are not yet supported in the distributions. Most distributions will have notes on known hardware problems often with solutions or workarounds. You should check these notes on-line, as opposed to from the installation media as problems may have been found after it was released, before trying to install as it could save you much frustration later.
If you want to test out your computer with Linux before trying to install, many different Linux distributors now have "LiveCD" versions which allow you to try the system without installing. The way these work is by ignoring your hard disk and simply treating your computer like a PlayStation, running everything from the CD. These systems cannot run as fast or be as flexible as a Linux system installed onto a hard disk, but they do give you a chance to test your computer and the system for compatibility and to try out the software to see how it suits your needs.

Partitioning your Hard Disk for Linux>>>>>>>>>>
As outlined in the General Information section, the most common way to install Linux is to allocate a part of your hard disk for Linux. Most computers come with one hard disk, and that hard disk is usually setup to have just one partition which uses all of the space on the hard disk. If this is the case with your computer, then you will need to either add a new hard disk for Linux, or shrink your existing partition to make space for Linux.
Each partition not only creates a separate independent space on the hard disk but it also associates a method of reading and writing information to the drive, the format of the drive. Linux has a number of different formats it can use for sections of the hard disk, the most popular being ext2 and ext3 (others include reiserfs, xfs and jfs). Normally you will not have to worry much about the formats of Linux partitions, the installation program will make appropriate suggestions. One other type of partition format for Linux which is worthy of mention is swap. A swap partition is used to effectively extend your memory onto the hard disk, so if your computer wants to use more memory then it has, it will "swap" information in memory which it doesn't need at the time onto the hard disk. It is possible to use a large file on a normal partition for swap however this is much slower. Unless you measure your memory in Gigabytes, you should probably use a swap partition at least the size of your memory, and if you have less then 256Megabytes of ram then you may want a partition 2 or 3 times it.
If you are in the common situation of having to shrink the only Windows partition on your hard disk, the first thing to be aware of is that your access to the information on the Windows partition will depend on its format. There are two main types of partition formats for Windows, FAT and NTFS. Generally computers with the Windows 95/98/ME systems will have FAT partitions and Windows NT/2000/XP will have NTFS partitions, though the NT/2000/XP family can also use FAT.
The critical difference between FAT and NTFS as far as Linux is concerned, is that while reading information from either system is perfectly safe under Linux, writing information to an NTFS partition is currently regarded as potentially unsafe so you wouldn't be able to edit these files from Linux and access the changes directly under Windows. Linux is perfectly reliable sharing FAT partitions with other operating systems (if your feeling lost, perhaps telling you that when you format a floppy you are actually making a FAT filesystem on it will help put things in perspective). Windows has no native method of reading Linux formatted partitions, but the Free explore2fs program allows you to read and copy information from ext2 and ext3 Linux partitions while you are running Windows. There is now also a file-system driver from the same source called ext2ifs which allows your ext2 and ext3 partitions to appear as extra drives in Windows NT4/2000/XP (still read only).
There are numerous methods for shrinking Windows partitions to make space for Linux (and I would recommend simply making the space and using the installer to create the partitions and format them). No matter what method you use to do this, you should backup all your data before you begin, in fact you should always keep backups of all your important information as a hard disk could fail at any time. Another tip is to defragment your drive in windows before you begin which makes it much easier for the software which has to do the shrinking. The tried and true method for shrinking a partition is a commercial program called Partition Magic ($69.95 as of Sept 2004). You can also do this with Free software such as parted (or the graphical front-end QTparted) or often as part of the installer itself. Check the installation documentation for the system you plan on installing to see if it's now supports resizing/shrinking ntfs partitions.
Whatever scenario you start in, when you begin to install Linux you need to know where you have space to put it. It may be a new hard disk or free space on an existing hard disk. For a modern desktop Linux system you would want to allocate an absolute minimum of 2GB of hard disk space, 5GB would be far better and if you have plenty of space (or if you plan to install lots of large pieces of software, perhaps games) 10GB+ is perfectly reasonable. If you have enough free space the installation program may suggest creating more than one Linux partition, if so it is well worthwhile creating a separate partition for your files, the /home partition. Amongst other things you can reinstall your system or install a new system without having to make an additional backup of your files (remember again you do always keep backups of everything important).

Partitioning your hardisk for linux

Booting Up>>>>>>>>> If you want to run Linux on your computer, first you are going to have to learn how your computer chooses what operating system to run, including how to choose to make it run Linux. When your computer is powered on, the bios (basic input/output system) takes control of your computer. The relevant fact for us now about the bios is that it decides where to look for software on the computer and what order to look at these places in. Usually computers will look to the hard disc for the software they will run, though often they will also check for a floppy disk, cd/dvd, network connection or flash memory which can be used to start the computer. Usually when you are installing an Operating System on to your computer, you will boot up from an installation cd/dvd to perform the installation, so your bios will need to be setup to check the cd/dvd before the hard disk. If you want to try out a LiveCD version of Linux, you will also need to have your bios setup similarly. If you are planning on installing Linux or running a LiveCD, you may be lucky and already find that your computer will boot from the cd/dvd drive. There is no harm in trying to put the cd in and then restarting your computer, if it starts up as normal then you will need to check and probably change the bios, if you see some new massages (probably mentioning Linux somewhere) then you can leave the bios alone and continue on to install Linux or try out that cd. To check or change the setup in your bios, you will need to restart your computer, and press a key to enter the setup function, before it starts to load any operating system. Usually you will need to press F1, F2, Escape or Delete, if there are no messages on the screen to tell you what to press (or if they go to fast to read them) you may have to consult your motherboard or computer manual. Once you enter the bios setup, you should look for instructions on how to use the setup, and ensure you do not save any changes you did not mean to make, as this could prevent your computer from booting up properly. Generally you will be looking for an option called "boot order" or similar and here you should have the chance to ensure the computer will check the cd/dvd drive before the hard disk. If you have to change the boot order, you will need to save your changes before you leave the bios setup (there is usually a "save and exit" option which will ask you to confirm that you want to make the changes). If you are unsure ask a friend to help! If you are unable to boot from a cd/dvd, perhaps the page Making a boot floppy to start from will help. When your bios is starting up the software on your computer, what it actually does is attempt to get a small piece of code, called a boot loader from each place it has been told to look, one at a time, in order. It uses the first copy of the information it finds to start loading software on to the computer. When the bios comes to look at hard disks for a boot loader, it looks at the very start of the disk, a space on the disk called the master boot record or mbr. Unless you have scsi hard disks (and if you don't know what this means assume you don't) then the bios will actually just check for an mbr on the "first" hard disk (the master disk on the first controller to be more precise). If you only have one operating system installed on your computer, all the software in the mbr needs to do is start that system. If you have multiple Operating Systems installed on your hard disk(s) then this mbr needs to offer you a way to choose between them and then start them up. When you are installing Linux, you will usually be given the chance to install grub or lilo as your boot loader, and also the chance to make a boot floppy (to use this your bios would need to check for floppy disks to boot from before the hard disk). Both grub and lilo will happily start other operating systems, and many Linux distributions will set this up automatically and so the recommended approach is to install one of these into the mbr. Alternatively you can install lilo or grub to the same partition as Linux (and NOT the mbr) and make the Windows NT/2000/XP boot loader offer a choice to start Linux. Finally on Windows 95/8 you can use loadlin to start Linux from dos. Always remember that if your computer is set to boot first from a removable device (cd/dvd or floppy) then it will always boot from this device if it can, so you will normally want to ensure there is no bootable disk in the drive when you start the computer. When you are finished installing Linux, or using a LiveCD, you should remove the cd/dvd from the drive before restarting your computer, letting your system boot up normally from the hard disk. Keep the disk safe though as in the event of a problem with your computer, you know have a rescue disk you can use to boot up and fix problems.