C.4. Collecting System Hardware Information
Before you choose a Linux distribution, use the considerable resources about Linux and Alpha on the Internet. Indeed, a wealth of detailed hardware information about Alpha chips and platforms designed to support it are available for downloading and printing, including generously supplied technical manuals that would be expensive to purchase (or unavailable) through marketing channels. Be aware that much useful documentation may be supplied by a different vendor than the manufacturer of your CPU or system and from other distribution resources as well.
C.4.1. Sources of Information
Following is a partial list of important Internet sources for Alpha hardware information and information about installing Linux on Alpha systems.
C.4.1.1. AlphaLinux sites
C.4.1.2. AlphaLinux mailing lists
C.4.2. CPU, Support Chipset, Board, and System Identification
There are four classes of Alpha CPU: the 21064, 21066, 21164, and 21264. The 21064 and 21066 classes are both first-generation Alpha architectures, but the 21066 incorporates functions normally supplied on support chips into the CPU itself, creating distinctive platform characteristics and requirements. The 21164 and 21264 classes represent second- and third-generation chip architectures, respectively. Various chip architectures have been coupled with different system busses and interfaces, which subdivide the CPU types into different families of Alpha computers from desktop systems to supercomputing clusters.
For purposes of installing Linux from a CD-ROM distribution, the subdivisions differ in the support that the Linux kernel provides for the features of the chips and in system assemblies and interfaces that use those features. If you cannot boot a kernel that appears to match your system, try a similar kernel from a related system or try a generic kernel. And, if that does not work, go to the AlphaLinux FTP site and try an earlier kernel or a later, developmental kernel. For the most part, however, your installation should be straightforward if you have selected the right image files to load and install Linux.
The subclass your system falls into determines whether you follow a routine Linux diskette-load installation procedure or use an alternative procedure. Even the routine AlphaLinux installation procedure is more complex than a Linux installation on the usual Intel PC. While the Intel PC provides the system hardware interface in the onboard BIOS, Alpha systems require that the system bootstrap itself by defining and loading a firmware interface before loading the operating system. For our installation purposes, we must usually use a firmware console that is resident on the system to load Milo (or another miniloader), which then loads Linux on the system.
Some systems have more than one firmware console interface, and most systems also have additional methods of bootstrapping an OS in firmware.
The standard firmware is initially loaded by accessing a system console when the system is booted and instructing it to load a Milo from diskette. Then the current Milo miniloader image is loaded from diskette, and it in turn is told to load the Linux kernel from the CD-ROM or boot diskette.
While you can get by using a slightly old Red Hat Milo for your hardware with the latest Red Hat Linux, you could not use a NetBSD Milo image (based on DU PALcode) or a Milo image prepared for a very different Alpha system. Milo must be compatible with the system firmware used to load it as well as the Linux kernel that it loads. For instance, a Milo designed for ARC may not work if loaded with SRM even if it is for the correct system. Sometimes system firmware must be updated before using it to load the Milo image into memory. AlphaBIOS firmware, in particular, is updated frequently, and if your system uses AlphaBIOS you should assume that you need to update it before installing Linux. Your CD-ROM distribution may contain images for updated AlphaBIOS, ARC, or SRM firmware, if there is a known need for the updated version.
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