Setting Up a Dual-Boot Environment

Sharing a computer between two operating systems requires dual booting. You can use either operating system on the computer but not both at once. Each operating system boots from and uses its own hard drives or disk partitions (a partition is a physical division on a hard drive).

For clarity, we will assume that the other operating system is Windows. But the general procedures are similar for other operating systems.

	Please Note
	If Red Hat Linux will coexist on your system with OS/2, you must create your disk partitions with the OS/2 partitioning software -- otherwise, OS/2 may not recognize the disk partitions. During the installation, do not create any new partitions, but do set the proper partition types for your Linux partition using `fdisk`.

Before starting the installation program, you must first make room for Red Hat Linux. Your choices are:

Add a new hard drive
Use an existing hard drive or partition
Create a new partition

Add a New Hard Drive

The simplest way to make room for Red Hat Linux is to add a new hard drive to the computer and then install Red Hat Linux on that drive. For example, if you add a second IDE hard drive to the computer, the Red Hat Linux installation program will recognize it as hdb and the existing drive (the one used by Windows) as hda. (With SCSI hard drives, the newly installed hard drive would be recognized as sdb and the other hard drive as sda.)

If you choose to install a new hard drive for Linux, you don't need to read any further. After starting the Red Hat Linux installation program, just make sure you tell it to install Linux on the newly installed hard drive (hdb, sdb) rather than the one Windows uses.

Use an Existing Hard Drive or Partition

The next simplest way to make room for Linux is to use a hard drive or disk partition that is currently being used by Windows. For example, suppose that Windows Explorer shows two hard drives, C: and D:. This could indicate either that the computer has two hard drives, or a single hard drive with two partitions. In either case (assuming it is large enough), you can install Red Hat Linux on the hard drive or disk partition that Windows recognizes as D:.

This choice is available to you only if the computer has two or more hard drives or disk partitions.

	Please Note
	Windows uses letters to refer to removable drives (for example, a ZIP drive) and network storage (virtual drives) as well as for local hard drive space: you cannot install Linux on a removable or network drive.

If a local Windows partition is available that you want to install Linux in, you don't need to read any further. Just do the following:

Copy all data you want to save from the selected hard drive or partition (D: in this example) to another location.
Start the Red Hat Linux installation program and tell it to install Linux in the designated drive or partition -- in this example, in the hard drive or partition that Windows designates as D:. Note that Linux distinguishes between hard drives and disk partitions. Thus:
- If C: and D: on this computer refer to two separate hard drives, the installation program will recognize them as hda and hdb (IDE) or sda and sdb (SCSI). Tell the installation program to use hdb or sdb.
- If C: and D: refer to partitions on a single drive, the installation program will recognize them as hda1 and hda2 (or sda1 and sda2). During the partitioning phase of Linux installation, you'll delete the second partition (hda2 or sda2), then partition the unallocated free space for Linux. (You don't have to delete the second partition prior to beginning Linux partitioning. But if you don't, Windows will complain whenever you boot that it cannot read Drive D; and should someone accidentally format D, your Linux system would be destroyed.)

Create a New Partition

The third way to make room for Linux is to create a new partition for Red Hat Linux on the hard drive being used by the other operating system. If Windows Explorer shows only one hard drive (C:), and you don't want to add a new hard drive, you must partition the drive. After partitioning, Windows Explorer will reveal a smaller C: drive; and, when you run the Red Hat Linux installation program, it will partition the remainder of the drive for Linux.

You can use a destructive partitioning program, such as fdisk, to divide the hard drive, but doing so will require you to re-install Windows. (This is probably not your best option.)

A number of non-destructive third-party partitioning programs are available for the Windows operating system. If you choose to use one of these, consult their documentation.

For instructions on how to partition with FIPS, a program that is on the Red Hat Linux CD-ROM, turn to the section called Partitioning with FIPS.