Console firmware is stored in a flash ROM and started when an Alpha system is powered up or reset. There are two different console specifications used on Alpha systems, and hence two classes of console firmware available:

From the user's perspective, the most important difference between SRM and ARC is that the choice of console constrains the possible disk-partitioning scheme for the hard disk which you wish to boot off of.

ARC requires that you use an MS-DOS partition table (as created by cfdisk) for the boot disk. Therefore MS-DOS partition tables are the ``native'' partition format when booting from ARC. In fact, since AlphaBIOS contains a disk partitioning utility, you may prefer to partition your disks from the firmware menus before installing Linux.

Conversely, SRM is incompatible with MS-DOS partition tables. ^[4] Since Tru64 Unix uses the BSD disklabel format, this is the ``native'' partition format for SRM installations.

GNU/Linux is the only operating system on Alpha that can be booted from both console types, but Debian GNU/Linux 3.1 only supports booting on SRM-based systems. If you have an Alpha for which no version of SRM is available, if you will be dual-booting the system with Windows NT, or if your boot device requires ARC console support for BIOS initialization, you will not be able to use the Debian GNU/Linux 3.1 installer. You can still run Debian GNU/Linux 3.1 on such systems by using other install media; for instance, you can install Debian woody with MILO and upgrade.

Because MILO is not available for any of the Alpha systems currently in production (as of February 2000), and because it is no longer necessary to buy an OpenVMS or Tru64 Unix license to have SRM firmware on your older Alpha, it is recommended that you use SRM when possible.

The following table summarizes available and supported system type/console combinations (see Section 2.1.2, “CPU, Main Boards, and Video Support” for the system type names). The word `ARC' below denotes any of the ARC-compliant consoles.

Generally, none of these consoles can boot Linux directly, so the assistance of an intermediary bootloader is required. For the SRM console, aboot, a small, platform-independent bootloader, is used. See the (unfortunately outdated) SRM HOWTO for more information on aboot.

The majority of AlphaServers and all current server and workstation products contain both SRM and AlphaBIOS in their firmware. For "half-flash" machines such as the various evaluation boards, it is possible to switch from one version to another by reflashing the firmware. Also, once SRM is installed, it is possible to run ARC/AlphaBIOS from a floppy disk (using the arc command). For the reasons mentioned above, we recommend switching to SRM before installing Debian GNU/Linux.

As on other architectures, you should install the newest available revision of the firmware ^[5] before installing Debian GNU/Linux. For Alpha, firmware updates can be obtained from Alpha Firmware Updates.

In SRM, Ethernet interfaces are named with the ewa prefix, and will be listed in the output of the show dev command, like this (edited slightly):

>>> show dev
ewa0.0.0.9.0               EWA0              08-00-2B-86-98-65
ewb0.0.0.11.0              EWB0              08-00-2B-86-98-54
ewc0.0.0.2002.0            EWC0              00-06-2B-01-32-B0

You first need to set the boot protocol:

>>> set ewa0_protocol bootp

Then check the medium type is correct:

>>> set ewa0_mode mode

You can get a listing of valid modes with >>>set ewa0_mode.

Then, to boot from the first Ethernet interface, you would type:

>>> boot ewa0 -flags ""

This will boot using the default kernel parameters as included in the netboot image.

If you wish to use a serial console, you must pass the console= parameter to the kernel. This can be done using the -flags argument to the SRM boot command. The serial ports are named the same as their corresponding files in /dev. Also, when specifying additional kernel parameters, you must repeat certain default options that are needed by the debian-installer images. For example, to boot from ewa0 and use a console on the first serial port, you would type:

>>> boot ewa0 -flags "root=/dev/ram ramdisk_size=16384 console=ttyS0"

Type

>>> boot xxxx -flags 0

where xxxx is your CD-ROM drive in SRM notation.