This section will walk you through pre-installation hardware setup, if any, that you will need to do prior to installing Debian. Generally, this involves checking and possibly changing firmware settings for your system. The “firmware” is the core software used by the hardware; it is most critically invoked during the bootstrap process (after power-up). Known hardware issues affecting the reliability of Debian GNU/Linux on your system are also highlighted.
There is normally no need to set up the BIOS (called OpenFirmware) on PowerPC systems. PReP and CHRP are equipped with OpenFirmware, but unfortunately, the means you use to invoke it vary from manufacturer to manufacturer. You'll have to consult the hardware documentation which came with your machine.
On PowerPC Macintoshes, you invoke OpenFirmware with Command-option-O-F while booting. Generally it will check for these keystrokes after the chime, but the exact timing varies from model to model. See http://www.netbsd.org/Ports/macppc/faq.html for more hints.
The OpenFirmware prompt looks like this:
ok 0 >
Note that on older model PowerPC Macs, the default and sometimes hardwired I/O for OpenFirmware user interaction is through the serial (modem) port. If you invoke OpenFirmware on one of these machines, you will just see a black screen. In that case, a terminal program running on another computer, connected to the modem port, is needed to interact with OpenFirmware.
The OpenFirmware on OldWorld Beige G3 machines, OF versions 2.0f1 and 2.4, is broken. These machines will most likely not be able to boot from the hard drive unless the firmware is patched. A firmware patch is included in the System Disk 2.3.1 utility, available from Apple at ftp://ftp.apple.com/developer/macosxserver/utilities/SystemDisk2.3.1.smi.bin. After unpacking the utility in MacOS, and launching it, select the Save button to have the firmware patches installed to nvram.
Many people have tried operating their 90 MHz CPU at 100 MHz, etc. It sometimes works, but is sensitive to temperature and other factors and can actually damage your system. One of the authors of this document over-clocked his own system for a year, and then the system started aborting the gcc program with an unexpected signal while it was compiling the operating system kernel. Turning the CPU speed back down to its rated value solved the problem.
The gcc compiler is often the first thing to die from bad memory modules (or other hardware problems that change data unpredictably) because it builds huge data structures that it traverses repeatedly. An error in these data structures will cause it to execute an illegal instruction or access a non-existent address. The symptom of this will be gcc dying from an unexpected signal.
The Linux Kernel cannot always detect what amount of RAM you have. If this is the case please look at Section 5.2, “Boot Parameters”.