Partitioning Rules
We
can have between zero and four primary partitions in each hard disk, or
we can have between zero and three primary partitions plus one extended
partition.
An extended partition can contain zero or more logical
partitions. Logical partitions must be 'contiguous' (arranged in a
series).
A partition that has its own entry in the partition table inside the hard disk's Master Boot Record is called a 'primary' partition.
The reason why can't have more than four primary partitions because there are only
four 16 byte spaces for partition details reserved in the
partition table.
A hard disk divided into the maximum of 4 primary partitions. No more partitions can be added.
They can all be different sizes, and there can be free spaces (gaps) in between.
There is a way to create more than just four primary partitions.
We can make one of them as an 'extended' partition instead of a regular primary partition.
An 'extended' partition is something like an empty box, and inside that we can create one or more 'logical' partitions.
By
using an extended type of partition and dividing it up into logical
partitions, we can divide a hard disk up into a great number of
partitions, many more than just four.
This is only possible if the 'logical' partitions can be 'contiguous'
or arranged in a series.
It's okay to make your extended partition first on the hard disk or in the middle of the hard disk.
Something
we can't do is
place a 'primary' partition in between two logical partitions or the
series of logical partitions will be broken and become unusable.
Logical partitions are strung together like a series circuit or a
chain.
It is okay to leave an empty space between logical partitions, but we
can't
place a 'primary' partition in between two logical partitions or the
series of logical partitions will be broken and become unusable.
For this reason it is best to plan ahead a little and try to make sure we
have room to add more 'primary' partitions or 'logical' partitions in
groups in our hard disks.
We probably don't want to use up out maximum of
four primary partitions too soon, it is a good idea to make an extended partition sometime before we run out.
What not to do:
We don't want to 'paint ourselves into a
corner' by 'boxing in' our extended partition by surrounding it with primary partitions.
In
the illustration above, the four partition limit is used up. The
extended partition is in between the primary partitions. There is free
space at the end of the disc, but no more partitions can be created.
What not to do:
In
this illustration all four partitions have been made as primary
partitions so no more partitions can be made in this hard disk, and
there is free space that can't be used.
It doesn't matter what you do as long as you're thinking ahead,
Linux partitions can be 'moved' these days with the latest versions of
GParted, but it can be a slow process. They can also be copied and
pasted into an equal or larger area of free space, providing the
partitioning rule won't be broken in the process.
If you can plan your partitions well to begin with it will save you some time and frustration in the long run.
Windows normally prefers to be installed and booted in a primary
partition, but
Linux can be installed in either 'primary' partitions or 'logical' partitions, it doesn't matter.
A typical partitioning scheme to begin with would be the simple
situation where Windows is installed in a primary partition that takes
up all of the hard disk.
Windows FAT32
/dev/hda1
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Ubuntu ext3
/dev/hda2 |
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The Ubuntu+FAT32 page
in this website shows how to resize Windows and
install Ubuntu in the newly created free space.
Ubuntu makes an ext3
partition for it's main part, or '/' (root filesystem), plus a small
swap area. A 'swap' area is like a page file, but it's in a partition.
By default, the swap area is logical but it really doesn't matter.
Windows with the FAT32 filesystem is the best for dual booting
with Linux because it's no problem to access Windows files from Ubuntu
and read and write to them.
Windows NTFS
/dev/hda1
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Ubuntu ext3
/dev/hda2
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In the Ubuntu+NTFS page, Windows XP Home Edition is resized smaller.
A
primary partition is made to install the Ubuntu / (root) file system in
and there's a logical partition for a FAT32 shared data partition.
Linux
has no problem writing to NTFS nowadays, but carefukl users might
still like to keep using a FAT32 shared data partition anyway. It
allows files being transferred between Linux and Windows to be scanned
for viruses. Linux is immune to viruses, but a virus can be
accidentally passed from Linux to Windows in certain types of files, so
it's best to scan them for viruses first.
There's a swap area at the end of the hard disk.
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Windows NTFS
/dev/hda1
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Ubuntu
'/ ' |
/home ext3
/dev/hda5 |
fat32
data
share
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Separate /home install resizes the Windows partition to a smaller size to
make room for the Linux partitions.
Then
it creates a Linux EXT3 operating system (root) partition
(primary). At first the files in / will only take up about 1.8
GB, but good size for a / partition would be at least 5.0 GB to allow
roon for adding software.
It makes a logical EXT3 /home partition, (logical), a FAT32 data
partition, (logical), and the remaining space is used as a swap
area.
If you find later on that you got your partition sizes wrong, or your needs have changed since you made the partitions, don't
worry about it. GParted -- LiveCD is free and only a small download and can do everything you need with all your partitions and filesystems.
It can even move Linux partitions from the start of the partition as well as the end.
NTFS is not a problem, GParted -- LiveCD can create NTFS filesystems too.
Partitioning Laptops
Normally laptops and a few desktops computers too, come with a small 'recovery' partition before the operating system partition.
Normally they don't take up very much hard disk space, so it would be best to just leave them alone.
Please
refer to the
instructions for your brand and model of computer to find out if you
can make or obtain your own Windows Installation Disc or Recovery CD,
in case the hard disk's partition table might ever get accidentally
corrupted somehow and the recovery partition can't help you.
What not to do:
Never
delete a recovery partition or any other partition unless you're sure
you will still be able to re-install your old operating system somehow
without it.
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What You might be able to do:
- Ask
your computer manufacturer to give you a proper 'Installation Disk' for
the software that you paid for when you purchased the computer, as
without that you really don't have the software permanently.
- You
may be able to use Partimage in Linux to make a carbon copy of your
other operating system and restore it from that image instead, if your
other operating system ever needs to be re-installed.
- You
may be able to go to BartPE website and make a BartePE LiveCD as a
Rescue Disk for your other operating system and once you have made that
you might be able to use files in your hard drive to further make your
own 'Installation CD'.
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Your Recovery partition might be given an entry in your new GRUB menu when you install Ubuntu.
If
it does, it might not be correctly labelled. You can edit the title for
it in your GRUB menu by editing your /boot/grub/menu.lst file in Ubuntu.
Make
sure you never boot the recovery partition by mistake. In some
computers it will erase and reformat your entire hard disk! At least it
might erase and reformat your other operating system.
Windows Default Dual Boot
Windows can normally only be installed and booted in a primary
partition, but sometimes it can be installed and booted in a logical
partition if it boots through another Windows installation.
For example,
Windows 98
installed originally
'boot' partition |
Windows XP,
installed in logical partition
depends on Windows 98 to boot it. |
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What you should not do if
you have a Windows dual boot set up by the Windows default method, is
to delete your Windows 98 install to install Ubuntu there. If you do
you will also be deleting the files Windows XP needs to boot, which
were transferred to Windows 98 when 'XP was installed.
If you do that you will be making a big mistake and I am not sure if it can be easily repaired.
Here is a great link on the subject: Understanding Multibooting and Booting Windows from an Extended Partition by Dan Goodall.
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Windows 98
'boot'
(primary)
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Windows XP
(logical) |
Ubuntu
(logical) |
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What you can do is simply reduce the size of your Windows XP logical
and install Ubuntu in a logical partition too. Ubuntu will boot just as
well in a logical partition, it makes no difference at all.
Also, if all the data is removed and Windows 98 is cleaned up, it can
be shrunk to a minimal size and really doesn't take up very much hard
disk space at all. The Windows XP partition can be moved with GParted -- LiveCD and that should make a little more room for Ubuntu.
Two Hard Disks
/dev/hda Ubuntu (primary master) (hd0,0)
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/dev/hdb Windows (primary slave) (hd1,0)
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People
wanting to dual boot with two (or more) hard disks should read this
great thread and links provided from it on the subject in Ubuntu Web
Forums. Dualboot Two Hard Drives
Thanks confused57 and lha, catlett, Sutekh, shoki, gn2, mingus,
bulldog, xpod, Bigbluecat and all other participants for the
information in these threads.
It is only a little bit more complicated to use two or more hard disks
for installing operating systems on. I have helped users with up to
seven hard disks. If they are all IDE or all SATA it is reasonably
trouble free. When IDE and SATA drives are together in the same
computer it can mean whatever bootloader you use might need a little
manual help to get fully configured. That's not usually too much of a
problem, it's relatively simple to figure out.
Windows and Linux Multiple Boot Arrangements
The small dark blue partition after Window is a dedicated grub partition. It
isn't vital to have a dedicated grub partition, but it can be an
improvement in a multiple boot Linux set-up.
I prefer to install each of my Linuxes as a single partition install,
all in one 'root' partition. (As opposed to having a separate /home).
That way I can multiple boot lots of operating systems without making
such a complicated mess of my hard disks. Each operating system is
independent. I like things better that way.
The red partition is the swap area that all my Linux operating systems share.
If you are going to try previewing and testing a new version of
Ubuntu before it is officially released, there is a smart way to do it.
You don't
need any data in it, (keep your data somewhere else), and you want to be able to restore your whole
partition in a hurry with most of your added software, settings and
updates.
The spare partition at the end of the disk could be used to
store compressed Partimage backups of my Hardy test installation.
If I get a bad update or try an experiment that causes some kind of
severe problems for my Hardy test install and I think it will be too
much work to repair it, I can just
delete the whole partition.
I can then just restore it again to an
earlier state from the Partimage backup. Aysiu has the best web page
about how to Use PartImage
Windows and Two Linux With a Shared /home
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Windows NTFS
/dev/hda1
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Ubuntu
Dapper
'/ ' |
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Kubuntu
Edgy
'/ '
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/home ext3
/dev/hda5 |
fat32
data
share
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In this type of partition arrangement two Linux operating systems are
sharing a common /home partition, and the swap area. Both operating
systems have access to the same files.
Of course, another thing we can do is install more than one desktop in
an operating system. I have one operating system that can be booted as
Ubuntu, Kubuntu or Xubuntu by selecting a different desktop at login.
There is no need to have separate partitions to try out different
desktops, just install as many different desktops as you like in the
one system. There are many more desktops available.
...but that's a subject for after you install!
For a different discussion on how you can partition your hard disks, please visit Aysiu's
Plan Partitions web page. Aysiu site features the Desktop CD installer, and Aysiu has a nice page about partitioning schemes there. You should read that one too. |
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