Multibooting

How To Run Several Operating Systems
on one computer

What's an Operating System? Click here.

It's as easy as inserting a CD

Your Hard Drive(s) need not be touched.

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Quickstart

How to Multiboot without affecting your Hard drive(s) - click here

Reference - (DOS & Windows only):

Microsoft Knowledge Base Article Q306559

NOTE: The wording of the MKB article is ambiguous. The terms "dual boot" and "multiboot" seem to be used interchangably. It's not clear whether they are talking about two, or three, or more OSes

Contents:

Third-party boot loaders

What's an Operating System?

or OS for short

An operating system is a program (actually a collection of programs) that tells a computer how to run itself. Like a car without a driver, a computer can't do anything without an operating system. Windows is an operating system, so are DOS, Macintosh OS X, UNIX, and Linux. There are many others.


Why would I want a multiboot computer?

Several possible reasons:

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Preparing Your Hard Drive(s)

Important points to ponder:

Recognized File Systems

  FAT12
(floppies)		 FAT16 FAT32 NTFS
DOS X X    
Win95/98/ME X X X  
WinNT X X   X
Win2K/XP/Vista X X X X

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Resizing or Changing existing Partitions - You don't need to wipe your drive and start over.

There are many tools available for non-destructive repartitioning. A very easy one to use is Power Quest's Partition Magic. Even the floppy disk version gives you a GUI with a mouse. It was recently acquired by Symantec, and it appears you can no longer download a demo version. Send me an email for other suggestions.

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Multibooting different versions of DOS and Windows

DOS and Windows 9x

This is tricky. The problem is that both DOS and Windows 9x want to take over the Master Boot Record. Neither is designed to recognize the existence of another OS. Win9x has a boot menu option (when you press F8 during startup) called "Previous version of MS-DOS". Setting it up is a pain in the rear. I wouldn't bother. Try GRUB or LILO. See below for instructions.

Alternatively, Microsoft has instructions to triple boot DOS, Windows 9x, and NT 4.0 on one machine - click here. It's rather complicated, and not for the technologically timid.

DOS and Windows NT and/or 2000 and/or XP

This is remarkably painless. Basically you just install them in order, as usual: install DOS, then NT, then 2000, then XP. Each (after DOS) will see the other installations and set up the multiboot capability. I would suggest you partition the hard disk ahead of time:

Drive OS Label Min Size Recommended File System Comments
C: DOS 6.22 dos622 10Mb 100Mb FAT16, or FAT12 if partition is under 16Mb Max partition size 2Gb; can't see FAT32 or NTFS
D: Windows NT 4.0 winnt 250Mb 500Mb FAT16 or NTFS Can't see FAT32; be sure to install Service Pack 6a
E: Windows 2000 win2k 1.5Gb 5Gb FAT16, FAT32, or NTFS Automatically upgrades other NTFS partitions
F: Windows XP winxp 1.5Gb 5Gb FAT16, FAT32, or NTFS Automatically upgrades other NTFS partitions

Use volume labels when you format. A volume label is just a name for a partition (drive). This makes them easy to identify when you are installing OSes.

  1. Install DOS, as you normally would, on drive C:. Use a DOS boot floppy to partition and format. If you use a Win98 boot floppy, any partitions larger than 512Mb will be FAT32, and unusable by DOS.
  2. Install NT on drive D:; it should see DOS on drive C: and automatically set up the dual boot capability.
  3. Install 2000 on drive E:; it should see DOS on drive C: and NT on D:, and set up multiboot capability.
  4. Install XP on drive F:; it should see DOS on drive C:, NT on D:, 2K on E:, and automatically set up the multiboot capability.

OTHER NOTES:

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Windows 9x and NT

This is ridiculously complicated, considering both these OSes are from the same company. It's far easier to dual boot Windows (any version) with Linux. You have to install NT twice. See the Microsoft Knowledge Base Article Q243896. If any of the hard drives are over 7.8Gb, it gets even worse; (see below).

Windows 9x and NT and a hard drive(s) larger than 7.8Gb

This is a colossal pain in the a**. NT will only recognize the first 7.8Gb (no matter what the drive size is). Simply using the 7.8 gigs NT can see is not the answer - it will freeze during the installation. As above, You have to install NT twice, and load a special ATAPI (IDE) device driver. The driver supposedly comes with Service Pack 4 and later, but you still have to install NT before you can install the Service Pack. See the Microsoft Knowledge Base Articles Q243896 and Q197667

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Windows 9x and 2000 and/or XP

Painless. Remember Win9x can't see NTFS drives. If you want to share files between it and 2k or XP, create another good sized FAT32 partition.

  1. Create a FAT32 C: drive; I recommend at least 1Gb
  2. Create a FAT32 D: drive, at least 1.5Gb (you can easily convert it to NTFS later if you want)
  3. Create a FAT32 E: drive, at least 1.5Gb (you can easily convert it to NTFS later if you want)
  4. Install Windows 9x on C: as usual
  5. Install Windows 2000 on D: as usual; it will see Win 9x on C: and set up the dual boot, you don't have to do a thing
  6. Install Windows XP on E: as usual; it will see Win 9x on C:, Win2k on D:, and set up the multi-boot, you don't have to do a thing

Done.

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Windows 2000 and XP

Easy. Do the same as above (Windows 9x and 2000 and/or XP), but leave out Win9x.

Multibooting without touching your hard drive(s)

So-called "live" CDs - the OS boots and runs entirely from a CD/DVD/USB stick/ZIP disk

There are distributions of Linux, called "live" distros, that boot and run entirely from a CD, DVD, or even floppy disks. They may create temporary files on your hard disk while running, but no existing files on your drive(s) are altered in any way.

There are hundreds of live distros. Many are created for very specific tasks: web servers, mail servers, firewalls, or routers, for example. Here are a few links:

KNOPPIX is a complete workstation on a bootable CD, with OpenOffice (MS compatible), Mozilla W3C compliant web browser, email, chat, IRC. Very impressive. Click here.
CAVEATS: it may not recognize very new or very old hardware or unusual hardware; it has a ton of drivers, but they can't include everything.

The List - A comprehensive list of Live Linuxes - click here.

Bart's PE (Pre-installed Environment) - you can make a Live CD version of Windows XP. It boots and runs entirely off the CD, just like Knoppix, above. Be warned, however: a) it will only work properly on the machine it was created with; b) it's not for the technologically timid - the documentation has very good step-by-step instructions, but it is complicated.

Bart's Homepage - click here.

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Installing Windows and Linux on the same computer (hard drive)

A several-step process; the first four steps only take about 10 minutes. I'm supposing you start with a single blank hard drive.

  1. Create a Primary partition of 5Gigs for Windows; this will be C: drive; CLICK HERE to learn more about partitioning and formating drives (go to Part 9 Hard Disks I).
  2. Create an Extended Partition that uses the rest of the drive.
  3. Create another 5Gig drive in the Extended Partition; You can leave the rest of the drive blank for now, and partition it later with either Windows or Linux.
  4. Format both drives as FAT32, and, THIS IS IMPORTANT:
    • give C: a volume label, such as WIN_C
    • give D: a volume label, such as LINUX
    This is so you can easily identify them later during the OS installation. You must format partitions before you can label them. You can change C: to NTFS during the Windows installation (if you want).
    NOTE that this drive D: will be invisible to Windows after you install Linux on it.
  5. (Optional) Create a FAT32 drive E: for sharing files between the two OSes, up to 32 gigs. Linux may have trouble writing to NTFS drives (read/copy is ok), because Microsoft won't tell anyone exactly how NTFS works. FAT32 is no problem. After installing Linux, this drive E: will appear to Windows as drive D: after you install Linux on the original drive D:.
  6. Install Windows (any version, 9x/ME/NT/2000/XP) as you normally would, on drive C:.
  7. Install Linux, any reasonably recent version should work fine. It will see Windows on C: and set up the dual boot. DO NOT let Linux "autoformat" the hard drive - it will probably wipe it out, and you'll have to start over.
    It will likely ask you:
    • which OS you want to be the default (the one that boots if you don't say anything otherwise)
    • what part of the hard drive to install itself on; make sure you point it to the 5Gb partition you created for it; you may have to delete it and recreate it, which is fine - just don't overwrite the Windows partition
    • which boot loader you want to use (LILO, or GRUB, or perhaps something else); just accept the defaults
  8. Lastly, it may ask where to put the boot loader - make sure it goes in the Master Boot Record (MBR) of the first hard drive
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Multibooting multiple versions of DOS/Windows, and Linux, from the same hard drive

This is no more complicated than the scenario above.

  1. Follow the steps above for installing various versions of DOS/Windows, using whatever combination of OSes you want, but REMEMBER to reserve at least a 5 Gig partition for Linux somewhere - anywhere, on any drive
  2. Install Linux, any reasonably recent version should work fine. It will see the other versions of DOS/Windows and set up the multi-boot. It may ask you:
    • which OS you want to be the default (the one that boots if you don't say anything otherwise), or
    • which boot loader you want to use (LILO, or GRUB, or perhaps something else)

NOTE that the initial boot menu might have items like Windows and Windows2 or Windowsb etc.; one of them will take you to the familiar Microsoft boot menu; you may need to experiment

I have successfully installed DOS 6.22, Windows 2000, Windows XP, FreeBSD, and Fedora (RedHat) Linux on the same computer, no problem.

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Using 2 or More Hard Drives

If you can get multiple OSes working on a single hard drive, you won't have any trouble with two or more hard drives. If you are only dealing with Microsoft products, you don't need to do anything special - just partition and install away, as described above. Much the same goes for Linux. It will figure out where everything is and install its boot loader. There are a few caveats, however. See below under drive and partition names.

Is there any advantage to having different OSes on different hard drives?

I can think of a few, but if you make regular backups, there is no particular advantage.

Partition Names (and Letters) and Multiple Hard Drives

Microsoft OSes count Primary Partitions first, then others. This means the first partition of the first drive (probably the Primary Master) will be C:, and the first partition of the next drive will be D:, whatever it is (Primary Slave, Secondary Master, Secondary Slave), etc. See below.

Let's take as an example a system with two drives, a Primary Master and Secondary Master, each with three partitions. In the two right-most columns I have added what Linux, LILO, and GRUB call the various partitions and drives. LILO uses the same naming convention as Linux; GRUB uses its own.

Drives, Partitions, and what various things call them

Drive Partition DOS/Win Linux/LILO GRUB
Primary Master 1 (Pri) C: /dev/hda1 (hd0,0)
  2 (Ext) E: /dev/hda5 (hd0,4)
  3 (Ext) F: /dev/hda6 (hd0,5)
Secondary Master 1 (Pri) D: /dev/hdb1 (hd1,0)
  2 (Ext) G: /dev/hdb5 (hd1,4)
  3 (Ext) H: /dev/hdb6 (hd1,5)

NOTES

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Graphical Representation

Single Hard Disk, Three Partitions

single hard disk with three partitions

Two Hard Disks, Three Partitions each

two hard disks, three partitions each

GRUB - The GRand Unified Boot loader

GRUB is potentially complex, but the basics aren't hard to grasp. It's powerful, versatile, and secure. It deserves a separate document.

CLICK HERE to learn about GRUB

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LILO - The LInux LOader (or any other OS)

LILO (or lilo) is also potentially complex, powerful and versatile, but less so than grub. The basics aren't hard to grasp. It also deserves a separate document.

CLICK HERE to learn about LILO

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Copyright © Michael Ward 1999 - 2008