Overview

Note that a partition is not a drive. A physical hard-drive usually has only 1 partition on it but may well have more. Windows calls a partition a 'drive' inaccurately.

Think of a Music Cd. A music Cd can have just 1 piece of music on it or it could have several songs. Each song is not a Cd. Think of a movie on Dvd. Again there might only be 1 film but there may be bonus features such as a theatrical trailer, deleted scenes. Or it might be a Dvd of a television series or perhaps a few short films on one Dvd. A film is not a Dvd. A Dvd with 4 films or episodes on it is not 4 Dvds.

Primary Partitions

When MicroSoft developed it's 'new' partition table type in around the 1980s it restricted the number of partitions a hard-drive could have to only 4. These have become known as "Primary Partitions". It would be inaccurate to think of this as the main episodes on a Dvd because these could be shorter than the bonus features.

Extended Partitions

Some clever people managed to make one of these a new type of partition that could hold a large number of other sub-partitions. This new type of partition became known as an "Extended Partition" (it should have been "Extending" not "Extended" but nevermind). Perhaps think of this as the bonus features menu on a Dvd. When you select "bonus features" it doesn't play anything, it just gives you another menu.

Logical Partitions

The sub-partitions became known as "Logical Partitions". When people quote the number of partitions on a drive they usually exclude the Extended Partition. Perhaps think of these as the the bonus features on a Dvd. However, the bonus features could be a lot longer than the movie or the episodes.

Normal Confusions

Windows needs to be installed on one partition. It can only really cope with one and if it can see another one then it seems to think it is another drive. Often Windows users may think they have 2 hard-drives even if they see it is 1 physical device. If they had 2 physical hard-drives, perhaps with 2 (or more) partitions on each, then they get very confused.

Which neatly brings us to another confusion. A hard-drive can have only 1 partition, it can have more but it can't have less (assuming it is being used). Yes, the name "partition" is very badly chosen because it does imply that there is more than 1. Before MicroSoft developed their operating systems it was assumed that every operating system would need to use more than 1 partition. So, since Windows is mostly restricted to 1 partition on 1 hard-drive it tries to reduce any confusion by calling that partition a drive, which is fine until we have 2 or more partitions on one physical drive.

To Edit, Create or Delete Partitions

The easiest way to do this is to use the program !GPartEd on the LiveCD of Ubuntu. (LiveCd just means boot-up (reboot) the machine with the normal Ubuntu Cd in the Cd/Dvd-drive). From the top taskbar/panel click on

System - Administration - "Partition Editor"

In the Ubuntu 10.04's (Lucid Lynx) menus it went back to being called GParEd for Ubuntu & Xubuntu and so Kubuntu uses QtPartEd (which is the Kde version and is almost identical).

Many other distros, not just Ubuntu, use these programs so if you are having trouble with it in Ubuntu you might find it better in the smaller and lighter sliTaz

• http://distrowatch.com/table.php?distribution=slitaz

or in the very specialist distro "GParted Live CD"

• http://distrowatch.com/table.php?distribution=gparted

Partitioning Scheme

Most drives have 1 Primary Partition with Windows installed. Often Laptops and some other machines have a tiny "Recovery Partition" in front of it. This is usually another Primary Partition but it is usually hidden (to avoid Windows getting confused and to stop people from accidentally over-writing anything on it).

Occasionally some machines have another partition for data. If this has been created with partition editors developed for Windows then it will probably be a "Logical Partition" (and therefore be inside an Extended Partition).

At the minimum Ubuntu will use 2 partitions

• one for the operating system itself

• a "Swap" partition to help Ram

An additional one for /home (for data) is a good idea and although you can make many more it is almost always better to keep things down to those 3. If you dual-boot or multi-boot with another linux distro then the swap and /home can be shared by them. It is even possible to share the /home with Windows if the /home's partition's "file-system" is NTFS or another Windows format.

Example Partitioning Scheme

• In general I make:
  • my Windows partition 20 - 30 Gb -- filesystem type NTFS (or can even be FAT32) and with the boot flag checked
  • my "extra" partition 2 Gb -- which I tend to format as filesystem FAT32 (but can be anything, including ext3). If this is a Windows recovery partition, I leave it unchanged.
  • my GRUB boot partition 50 - 100 Mb -- formatted to filesystem type ext3
  • the extended partition is the remainder
  • (At the end of the hard drive I usually leave a few Gb of free space (to allow for extra logical partition needs that I have not foreseen). This can't be done unless the extended partition is the last partition.)
• I then divide the extended partition into logical partitions:
  • a /swap logical partition that is 2 Gb -- filesystem type linux-swap
  • a logical partition for the / (root) folder of each planned OS (at least 10 Gb each, but 20-50 Gb is better) -- formatted as ext3 (or ext4 if you are planning to use a newer Linux OS)
  • a logical partition for each specific use, such as for a groupware partition (like Kolab, for example). I make this about 20 Gb and format it as ext3, since most specific uses (like Kolab) will be comfortable with ext3. Anther example is creating a partition for the /home directory.

Other resources

• This page was adapted from Ubuntuguide -- Multiple OS Installation.

• Psychocats Guide to Partitioning