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Chapter 7. Booting the Installer

7.1. Starting the Installation Program
7.1.1. Booting the Installation Program on x86, AMD64, and Intel 64 Systems
7.1.2. Additional Boot Options
7.2. The Boot Menu
7.3. Installing from a Different Source
7.4. Booting from the Network using PXE

Important — UEFI for 32-bit x86 systems

Red Hat Enterprise Linux 6 does not support UEFI for 32-bit x86 systems.

Important — UEFI for AMD64 and Intel 64

Note that the boot configurations of UEFI and BIOS differ significantly from each other. Therefore, the installed system must boot using the same firmware that was used during installation. You cannot install the operating system on a system that uses BIOS and then boot this installation on a system that uses UEFI.
Red Hat Enterprise Linux 6 supports version 2.2 of the UEFI specification. Hardware that supports version 2.3 of the UEFI specification or later should boot and operate with Red Hat Enterprise Linux 6, but the additional functionality defined by these later specifications will not be available. The UEFI specifications are available from http://www.uefi.org/specs/agreement/
To start the installation program from a Red Hat Enterprise Linux DVD or from minimal boot media, follow this procedure:
  1. Disconnect any external FireWire or USB disks that you do not need for installation. Refer to Section 3.3.3, “ FireWire and USB Disks ” for more information.
  2. Power on your computer system.
  3. Insert the media in your computer.
  4. Power off your computer with the boot media still inside.
  5. Power on your computer system.
You might need to press a specific key or combination of keys to boot from the media. On most computers, a message appears briefly on the screen very soon after you turn on the computer. Typically, it is worded something like Press F10 to select boot device, although the specific wording and the key that you must press varies widely from computer to computer. Consult the documentation for your computer or motherboard, or seek support from the hardware manufacturer or vendor.
If your computer does not allow you to select a boot device as it starts up, you might need to configure your system's Basic Input/Output System (BIOS) to boot from the media.
To change your BIOS settings on an x86, AMD64, or Intel 64 system, watch the instructions provided on your display when your computer first boots. A line of text appears, telling you which key to press to enter the BIOS settings.
Once you have entered your BIOS setup program, find the section where you can alter your boot sequence. The default is often C, A or A, C (depending on whether you boot from your hard drive [C] or a diskette drive [A]). Change this sequence so that the DVD is first in your boot order and that C or A (whichever is your typical boot default) is second. This instructs the computer to first look at the DVD drive for bootable media; if it does not find bootable media on the DVD drive, it then checks your hard drive or diskette drive.
Save your changes before exiting the BIOS. For more information, refer to the documentation that came with your system.

Note — Aborting the Installation

To abort the installation, either press Ctrl +Alt+Del or power off your computer with the power switch. You may abort the installation process without consequence at any time prior to selecting Write changes to disk on the Write partitioning to disk screen. Red Hat Enterprise Linux makes no permanent changes to your computer until that point. Please be aware that stopping the installation after partitioning has begun can leave your computer unusable.

7.1. Starting the Installation Program

Important — UEFI for 32-bit x86 systems

Red Hat Enterprise Linux 6 does not support UEFI for 32-bit x86 systems.

Important — UEFI for AMD64 and Intel 64

Note that the boot configurations of UEFI and BIOS differ significantly from each other. Therefore, the installed system must boot using the same firmware that was used during installation. You cannot install the operating system on a system that uses BIOS and then boot this installation on a system that uses UEFI.
Red Hat Enterprise Linux 6 supports version 2.2 of the UEFI specification. Hardware that supports version 2.3 of the UEFI specification or later should boot and operate with Red Hat Enterprise Linux 6, but the additional functionality defined by these later specifications will not be available. The UEFI specifications are available from http://www.uefi.org/specs/agreement/
To start, first make sure that you have all necessary resources for the installation. If you have already read through Chapter 3, Planning for Installation on the x86 Architecture, and followed the instructions, you should be ready to start the installation process. When you have verified that you are ready to begin, boot the installation program using the Red Hat Enterprise Linux DVD or any boot media that you have created.

Note

Occasionally, some hardware components require a driver update during the installation. A driver update adds support for hardware that is not otherwise supported by the installation program. Refer to Chapter 6, Updating drivers during installation on Intel and AMD systems for more information.

7.1.1. Booting the Installation Program on x86, AMD64, and Intel 64 Systems

You can boot the installation program using any one of the following media (depending upon what your system can support):
  • Red Hat Enterprise Linux DVD — Your machine supports a bootable DVD drive and you have the Red Hat Enterprise Linux installation DVD.
  • Boot CD-ROM — Your machine supports a bootable CD-ROM drive and you want to perform network or hard drive installation.
  • USB flash drive — Your machine supports booting from a USB device.
  • PXE boot via network — Your machine supports booting from the network. This is an advanced installation path. Refer to Chapter 30, Setting Up an Installation Server for additional information on this method.
To create a boot CD-ROM or to prepare your USB flash drive for booting or installation, refer to Section 2.3, “Making Minimal Boot Media”.
Insert the boot media and reboot the system.
You might need to press a specific key or combination of keys to boot from the media. On most computers, a message appears briefly on the screen very soon after you turn on the computer. Typically, it is worded something like Press F10 to select boot device, although the specific wording and the key that you must press varies widely from computer to computer. Consult the documentation for your computer or motherboard, or seek support from the hardware manufacturer or vendor.
If your computer does not allow you to select a boot device as it starts up, you might need to configure your system's Basic Input/Output System (BIOS) to boot from the media.
To change your BIOS settings on an x86, AMD64, or Intel 64 system, watch the instructions provided on your display when your computer first boots. A line of text appears, telling you which key to press to enter the BIOS settings.
Once you have entered your BIOS setup program, find the section where you can alter your boot sequence. The default is often C, A or A, C (depending on whether you boot from your hard drive [C] or a diskette drive [A]). Change this sequence so that the DVD is first in your boot order and that C or A (whichever is your typical boot default) is second. This instructs the computer to first look at the DVD drive for bootable media; if it does not find bootable media on the DVD drive, it then checks your hard drive or diskette drive.
Save your changes before exiting the BIOS. For more information, refer to the documentation that came with your system.
After a short delay, a screen containing the boot: prompt should appear. The screen contains information on a variety of boot options. Each boot option also has one or more help screens associated with it. To access a help screen, press the appropriate function key as listed in the line at the bottom of the screen.
As you boot the installation program, be aware of two issues:
  • Once the boot: prompt appears, the installation program automatically begins if you take no action within the first minute. To disable this feature, press one of the help screen function keys.
  • If you press a help screen function key, there is a slight delay while the help screen is read from the boot media.
Normally, you only need to press Enter to boot. Be sure to watch the boot messages to review if the Linux kernel detects your hardware. If your hardware is properly detected, continue to the next section. If it does not properly detect your hardware, you may need to restart the installation and use one of the boot options provided in Chapter 28, Boot Options.

7.1.2. Additional Boot Options

While it is easiest to boot using a DVD and perform a graphical installation, sometimes there are installation scenarios where booting in a different manner may be needed. This section discusses additional boot options available for Red Hat Enterprise Linux.
To pass options to the boot loader on an x86, AMD64, or Intel 64 system, use the instructions as provided in the boot loader option samples below.

Note

Refer to Chapter 28, Boot Options for additional boot options not covered in this section.
  • To perform a text mode installation, at the installation boot prompt, type:
    linux text
  • To specify an installation source, use the linux repo= option. For example:
    linux repo=cdrom:device
    linux repo=ftp://username:password@URL
    linux repo=http://URL
    linux repo=hd:device
    linux repo=nfs:options:server:/path
    linux repo=nfsiso:options:server:/path
    In these examples, cdrom refers to a CD or DVD drive, ftp refers to a location accessible by FTP, http refers to a location accessible by HTTP, hd refers to an ISO image file accessible on a hard drive partition, nfs refers to an expanded tree of installation files accessible by NFS, and nfsiso refers to an ISO image file accessible by NFS.
  • ISO images have an SHA256 checksum embedded in them. To test the checksum integrity of an ISO image, at the installation boot prompt, type:
    linux mediacheck
    The installation program prompts you to insert a DVD or select an ISO image to test, and select OK to perform the checksum operation. This checksum operation can be performed on any Red Hat Enterprise Linux DVD. It is strongly recommended to perform this operation on any Red Hat Enterprise Linux DVD that was created from downloaded ISO images. This command works with the DVD, hard drive ISO, and NFS ISO installation methods.
  • If you need to perform the installation in serial mode, type the following command:
    linux console=<device>
    For text mode installations, use:
    linux text console=<device>
    In the above command, <device> should be the device you are using (such as ttyS0 or ttyS1). For example, linux text console=ttyS0.
    Text mode installations using a serial terminal work best when the terminal supports UTF-8. Under UNIX and Linux, Kermit supports UTF-8. For Windows, Kermit '95 works well. Non-UTF-8 capable terminals works as long as only English is used during the installation process. An enhanced serial display can be used by passing the utf8 command as a boot-time option to the installation program. For example:
    linux console=ttyS0 utf8

7.1.2.1. Kernel Options

Options can also be passed to the kernel. For example, to apply updates for the anaconda installation program from a USB storage device enter:
linux updates
For text mode installations, use:
linux text updates
This command results in a prompt for the path to the device that contains updates for anaconda. It is not needed if you are performing a network installation and have already placed the updates image contents in rhupdates/ on the server.
After entering any options, press Enter to boot using those options.
If you need to specify boot options to identify your hardware, please write them down. The boot options are needed during the boot loader configuration portion of the installation (refer to Section 9.16, “x86, AMD64, and Intel 64 Boot Loader Configuration” for more information).
For more information on kernel options refer to Chapter 28, Boot Options.