Installations Using MILO
To boot Red Hat Linux using MILO, you will need to use some version of either the ARC or AlphaBIOS console, plus the linload.exe program.
The ARC and AlphaBIOS consoles are designed to load the Windows NT operating system. Like many other things in the Linux world, they're being used to do a job that they were never intended to do. In this case, they're used to load Linux. When you power-on an ARC/AlphaBIOS console machine, you will see the firmware initialize the hardware, and you will see a boot menu. The initialization process varies greatly by machine.
The ARC and AlphaBIOS consoles operate in essentially the same way. Both use MILO and, aside from cosmetic changes, they are identical in functionality. The keystrokes described in each section have been tested against ARC and AlphaBIOS systems, and are known to work with on-site machines. However, small differences may exist for other ARC and AlphaBIOS systems.
The Windows NT ARC/AlphaBIOS firmware is an environment in which programs (for example, the Windows NT osloader) can run and make callbacks into the firmware to perform actions.
Linux's linload.exe is a simple program which does just enough to load and execute MILO. linload.exe loads the appropriate image file into memory at 0x00000000 and then makes a swap-PAL PALcall to the image file. The swap is necessary because MILO, like Linux, uses a different PALcode than Windows NT. MILO relocates itself to 0x200000 and continues on through the PALcode reset entry point as before.
Setting up ARC for Installation
If you are using MILO and ARC to boot the installation program from the CD-ROM, you will only need a MILO image diskette.
If you are using MILO and ARC, but you are not booting the installation program from the CD-ROM, you will need to make three diskettes:
The correct MILO image diskette for the class of machine onto which you are installing Red Hat Linux. The MILO images, in compressed format, are located in the milo/images directory on CD 1. See the section called Choosing Disk Images if you are not sure which MILO image to use.
A generic kernel diskette, made from images/generic.img on CD 1.
The RAM disk diskette, made from images/ramdisk.img on CD 1.
Please refer to Appendix D for instructions on writing image files to diskettes.
Once you have created these diskettes, boot your Alpha machine into the ARC boot menu. The first step is to set up a boot menu entry to enable MILO to be loaded from the diskette. At the boot menu, select the option Supplementary menu.
Next, select the command: Set up the system, which takes you to the Setup Menu. From here, select the command Manage boot selection menu, which takes you to the Boot Selections Menu.
You need to add a boot command to load MILO from the diskette you created. Choose the command Add a boot selection.
You should see several devices listed. To select the A: drive, choose Floppy Disk 0.
 | Please Note |
|---|---|
If you do not see an entry for the diskette drive, consult your AlphaBIOS/ARC installation manual to determine the correct method for configuring your hardware in the console. |
Next, enter the name of the OS loader to use. Enter \linload.exe as the OS loader directory and name. The MILO disk you created has the linload.exe file on it, and the correct MILO for your Alpha machine class. The MILO command is always named milo on the diskette, and both files should reside in the root directory of the diskette.
Select the yes option when you are asked if the operating system is on the same partition as the OS loader (it is, both are in the root directory), and enter \ as the operating system root directory. As the name of the boot selection, enter something descriptive like MILO Diskette to indicate that this entry boots MILO from the diskette drive.
If prompted, select no to indicate that you do not want to start the debugger at boot time.
You should now be back in the boot selections menu. Press
You should have a boot selection that looks something like this:
LOADIDENTIFIER=Linux SYSTEMPARTITION=multi(0)disk(0)fdisk(0) OSLOADER=multi(0)disk(0)fdisk(0)\linload.exe OSLOADPARTITION=multi(0)disk(0)fdisk(0)\ OSLOADOPTIONS= |
This boot selection enables ARC to boot into MILO from the diskette using the linload.exe OS loader.
Setting up AlphaBIOS for Installation
First, you will need to install the latest version of AlphaBIOS, which can be obtained from Compaq's Alpha Firmware update site at
http://ftp.digital.com/pub/DEC/Alpha/firmware/ |
As with ARC, if you can boot from the CD-ROM, you will only need to make a MILO disk. If your machine can not boot from the CD-ROM, you will need three diskettes for the MILO installation process:
The correct MILO diskette for the class of machine onto which you are installing Red Hat Linux. The MILO images, in compressed format, are located in the milo/images directory on CD 1. See the section called Choosing Disk Images if you are not sure which MILO image you need.
A generic installation kernel diskette, from images/generic.img on CD 1.
A RAM disk diskette, made from images/ramdisk.img on CD 1.
Please refer to Appendix D for instructions on writing image files to diskettes.
Once your AlphaBIOS is at the latest revision level, you can start the
installation process. Turn on the system and insert the MILO
diskette. At the opening screen, press
Press
At this point, AlphaBIOS may display an error message such as Warning: Operating System Selection not valid!
Ignore this error (AlphaBIOS considers it an error whenever your OS is
not Windows NT). Press
Press
AlphaBIOS will load linload.exe, which will in turn load MILO.
The MILO User Interface
Once the Windows NT firmware is running and you have the correct MILO image for your system loaded, the rest of the installation details are completely generic.
Once you boot into MILO, you get a prompt that is very familiar to the standard bash# prompt in Linux. As mentioned earlier, MILO uses native Linux device drivers; therefore, all devices in MILO are referred to in the same manner as a running Linux system (/dev/scd0 for a SCSI CD-ROM 0, /dev/hda for the first IDE device, etc.).
MILO has a very simple interface that is designed to allow you to boot a Linux kernel image, and perform some basic diagnostic functions. Typing help is a good idea, since it provides a useful summary of the commands, as follows:
MILO> help
MILO command summary: ls [-t fs] [dev:[dir]]
- List files in directory on device
boot [-t fs] [dev:file] [boot string]
-
Boot Linux from the specified device and file
run [-t fs] dev:file
- Run the standalone program dev:file
show -
Display all known devices and file systems
set VAR VALUE -
Set the variable VAR to the specified VALUE
unset VAR - Delete the specified variable
reset - Delete all variables
print - Display current variable settings
help [var] - Print this help text
Devices are specified as: fd0, hda1, hda2, sda1...
Use the '-t filesystem-name' option if you want
to use anything but the default filesystem ('ext2').
Use the 'show' command to show known devices and file-
systems.
Type 'help var' for a list of variables. |
| Please Note |
|---|---|
The bootopt command only appears on AlphaPC64 (and similar) systems. Refer to the board's documentation to find out just what it means. |
Devices
Until you use a command that needs to make use of a device, no device initialization will take place. The first time you issue the show, ls, or run command, the devices within MILO will be initialized. Devices are named exactly the same way that Linux names devices. So, the first IDE drive will be called hda and its first partition will be hda1. Use the show command to show what devices are available.
Filesystems
MILO supports three filesystems: MSDOS, ext2 and ISO9660. If a device is available to it, MILO can ls, boot or run an image stored on one of these filesystems. MILO will assume ext2 as the default filesystem, and so you have to explicitly tell MILO if the filesystem is something other than ext2. All of the commands that use filenames allow you to pass the file system using the -t [filesystem] option. So, if you wanted to list the contents of a SCSI CD-ROM, you might type the following:
MILO> ls -t iso9660 scd0: |
Variables
MILO provides certain variables to help the boot process. If you are loading via Windows NT ARC or AlphaBIOS firmwares, then MILO makes use of the boot option environment variables set up by that firmware. For some systems (for example, the AlphaPC64), MILO maintains its own set of environment variables that do not change from boot to boot. These variables can be displayed with the help var command:
MILO> help var Variables that MILO cares about: MEMORY_SIZE - System memory size in megabytes BOOT_DEV - Specifies the default boot device BOOT_FILE - Specifies the default boot file BOOT_STRING - Specifies the boot string to pass to the kernel SCSIn_HOSTID - Specifies the host id of the n-th SCSI controller PCI_LATENCY - Specifies the PCI master device latency AUTOBOOT - If set, MILO attempts to boot on powerup and enters command loop only on failure. AUTOBOOT_TIMEOUT - Seconds to wait before auto- booting on powerup. |
| Please Note |
|---|---|
If you set AUTOBOOT, you need to set the timeout. Setting AUTOBOOT without setting the timeout can result in your machine automatically booting after a timeout of 0 seconds, which will not allow for any user intervention in the case of errors. |
Booting with MILO
The primary function of MILO is to boot the Linux kernel. To boot the installation program to use the CD-ROM (assuming the CD-ROM drive is SCSI) the command would look similar to this:
MILO> boot scd0:/kernels/generic.gz root=/dev/scd0 |
Note that the above command may be different for your system, because it depends upon how your system and its CD-ROM drive are set up.
To boot from the diskette, put the generic.img diskette into the diskette drive and type in the following command:
MILO> boot fd0: |
The installation program should boot, and you should be able to proceed as normal. IDE CD-ROM devices use the standard IDE device references. You will see output like the following:
available configurations: linux (or 'halt' to return back to MILO prompt) boot: |
Type in linux and press
If needed, you will be prompted to place the RAM disk diskette in the diskette drive, and then the installation should begin.
Installation
Refer to Chapter 4 for instructions on the graphical installation process. The next MILO-specific step you will need to take is the installation of MILO to your hard drive, which should be done after the packages have been installed (see the section called Installing Packages in Chapter 4). Instructions for installing MILO to the hard drive are as follows:
Stop when the packages you've selected are finished being transferred to the hard drive. At this point, the packages have been installed and you will need to press the Next button to finish the installation. Do NOT press the Next button yet. Instead, use the following instructions to install MILO to your hard drive.
The installation process puts all the necessary components of the
Red Hat Linux operating system on your machine, but MILO must be installed
manually. Switch to the command prompt on the second virtual console
by pressing
Move to the /mnt/sysimage directory and temporarily make /mnt/sysimage the root directory with these commands:
# cd /mnt/sysimage # /usr/sbin/chroot . |
Now, you must install MILO. First, insert your MILO diskette into the diskette drive. Then you will need to issue a command which will vary slightly in syntax, depending on your boot device. For example, if you plan to boot your Alpha from the first SCSI hard disk, issue the following command:
bash# dd if=/dev/fd0 of=/dev/sda1 |
If you plan to boot your Alpha from the second IDE device, the dd command should be executed like this:
bash# dd if=/dev/fd0 of=/dev/hdb1 |
The command will copy MILO (along with linload.exe) to the small MILO partition you created. Once MILO has been installed, type the following command to exit the temporary root device set using the chroot command:
bash# exit |
Now switch back to the GUI using