Considerations for Dual Booting

Many users need more than one operating system in their daily computer use. It's not uncommon, for example, to set up a single machine with Windows 2000 for business applications and XP Home as a gaming platform. One OS for work, one for play.

One way to implement this is with removable hard drives, each with a different OS. This, however, takes some degree of hardware expertise, not to mention added expense and a computer case that supports it. Another option is a program called Virtual PC. With Virtual PC, you can launch a new window from within the XP operating system, which is a "second machine." This second machine can run an entirely different OS, complete with entirely different applications and settings. More about the Virtual PC can be found at www.microsoft.com/windows/virtualpc.

Another common solution is to configure a dual-boot machine. When you do, you get a choicea boot menuat startup time that lets you decide which OS to boot. The process for setting up dual boot is pretty straightforward. The only thing it takes is a little planning on your part.

First you must decide how much space the operating systems need, and then you must partition your hard drive accordingly. If you accept some of the defaults when installing XP (during the initial portion where you decide where to install), you create only a single partition that takes up the entire drive. You can run two operating systems out of the same partition, but it is not recommended. Seriously. If you mention this to Microsoft, they will halt their support efforts.

After partitioning, go ahead with the OS install. For example, if you want to run both XP and Server 2003 on the same machine, you should probably partition the hard drive into a C:\ drive and D:\ drive. You don't even have to use all the space; you can create some space on the unpartitioned drive and decide how to use it later on.

In days past, you had to boot to a floppy disk and run special utilities that partitioned hard disks. Fortunately, you can now do the same thing while running the XP installation routine. All you have to do is boot from the Windows XP CD and follow the initial installation screens that ask you how and where you want to install.

When you're done with the new XP installation, you can then insert the Windows Server 2003 CD and begin its installation routine. Be careful, though. A few hurried clicks can have you upgrading the operating system rather than installing a second one. You'll reboot, and your XP installation will have scattered to the winds. If you don't choose to boot from the Server 2003 CD, just make sure you choose the "New Installation" selection, as shown in Figure 4-6.

Figure 4-6. Install a second operating system on an XP machine.

When configuring dual booting, you should be mindful of certain dual-boot partitioning considerations.

System v. Boot Partitions

This may seem backward, but the system partition holds the files needed to boot the computer. The operating system installation, on the other handthe partition that holds the \WINDOWS directoryis called the boot partition. Got it? The system partition holds the boot files; the boot partition holds the operating system.

Can the system and boot partitions be on the same drive? Absolutely. In fact, on most systems, they are. Look at your computer. If you have just one big C:\ drive, the system and boot partitions are the same. The system and boot partitions are identified in Disk Management.

The issues discussed in the "System v. Boot Partitions" sidebar can be very significant under certain dual-booting circumstances. If, for example, you want to boot into a previous Windows version that supports only FAT, such as Windows 98, you need to ensure that the system partition is formatted with the FAT file system. If the system partition is formatted with NTFS, Windows 98 won't be able to read the files needed to start up, and the boot process will subsequently fail. If booting to any combination of Windows 2000, Server 2003, and XP, the NTFS file system can be used across the board.

When to Install XP Last

If setting up to dual boot for XP and Windows 2000, install XP last. If you don't, you run into an installation "issue" documented in Microsoft Knowledge Base article Q283433. To paraphrase: it's fixable; you just need to start the computer in Windows 2000 and then copy the NTLDR and Ntdetect.com files from the I386 folder on the Windows XP CD-ROM to the root of the system drive.