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<sect1 id="pre-install-bios-setup">
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<title>Pre-Installation Hardware and Operating System Setup</title>
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This section will walk you through pre-installation hardware setup, if
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any, that you will need to do prior to installing Debian. Generally,
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this involves checking and possibly changing firmware settings for
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your system. The ``firmware'' is the core software used by the
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hardware; it is most critically invoked during the bootstrap process
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(after power-up). Known hardware issues affecting the reliability of
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&debian; on your system are also highlighted.
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&bios-setup-powerpc.xml;
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&bios-setup-sparc.xml;
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<sect2><title>Hardware Issues to Watch Out For</title>
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<para arch="not-s390">
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Many people have tried operating their 90 MHz CPU at 100 MHz, etc. It
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sometimes works, but is sensitive to temperature and other factors and
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can actually damage your system. One of the authors of this document
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over-clocked his own system for a year, and then the system started
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aborting the <command>gcc</command> program with an unexpected signal
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while it was compiling the operating system kernel. Turning the CPU
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speed back down to its rated value solved the problem.
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</para><para arch="not-s390">
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The <command>gcc</command> compiler is often the first thing to die
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from bad memory modules (or other hardware problems that change data
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unpredictably) because it builds huge data structures that it
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traverses repeatedly. An error in these data structures will cause it
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to execute an illegal instruction or access a non-existent
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address. The symptom of this will be <command>gcc</command> dying from
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</para><para arch="m68k">
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Atari TT RAM boards are notorious for RAM problems under Linux; if you
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encounter any strange problems, try running at least the kernel in
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ST-RAM. Amiga users may need to exclude RAM using a booter memfile.
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<phrase condition="FIXME"><emphasis>
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FIXME: more description of this needed.
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</para><para arch="i386">
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The very best motherboards support parity RAM and will actually tell
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you if your system has a single-bit error in RAM. Unfortunately, they
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don't have a way to fix the error, thus they generally crash
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immediately after they tell you about the bad RAM. Still, it's better
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to be told you have bad memory than to have it silently insert errors
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in your data. Thus, the best systems have motherboards that support
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parity and true-parity memory modules; see
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<xref linkend="Parity-RAM"/>.
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</para><para arch="i386">
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If you do have true-parity RAM and your motherboard can handle it, be
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sure to enable any BIOS settings that cause the motherboard to
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interrupt on memory parity errors.
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<sect3 arch="i386"><title>The Turbo Switch</title>
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Many systems have a <emphasis>turbo</emphasis> switch that controls
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the speed of the CPU. Select the high-speed setting. If your BIOS
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allows you to disable software control of the turbo switch (or
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software control of CPU speed), do so and lock the system in
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high-speed mode. We have one report that on a particular system, while
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Linux is auto-probing (looking for hardware devices) it can
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accidentally touch the software control for the turbo switch.
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<sect3 arch="i386"><title>Cyrix CPUs and Floppy Disk Errors</title>
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Many users of Cyrix CPUs have had to disable the cache in their
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systems during installation, because the floppy disk has errors if
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they do not. If you have to do this, be sure to re-enable your cache
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when you are finished with installation, as the system runs
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<emphasis>much</emphasis> slower with the cache disabled.
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We don't think this is necessarily the fault of the Cyrix CPU. It may
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be something that Linux can work around. We'll continue to look into
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the problem. For the technically curious, we suspect a problem with
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the cache being invalid after a switch from 16-bit to 32-bit code.
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<sect3 arch="i386"><title>Peripheral Hardware Settings</title>
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You may have to change some settings or jumpers on your computer's
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peripheral cards. Some cards have setup menus, while others rely on
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jumpers. This document cannot hope to provide complete information on
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every hardware device; what it hopes to provide is useful tips.
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If any cards provide ``mapped memory'', the memory should be mapped
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somewhere between 0xA0000 and 0xFFFFF (from 640K to just below 1
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megabyte) or at an address at least 1 megabyte greater than the total
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amount of RAM in your system.
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<sect3 arch="i386" id="usb-keyboard-config"><title>USB keyboards</title>
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If you have no AT-style keyboard and only a USB model, you will need
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to enable legacy AT keyboard emulation in your BIOS setup. Consult
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your main board manual and look in the BIOS for "Legacy keyboard
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emulation" or "USB keyboard support" options. It must be enabled in
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order to boot the installation system. If you enabled this option and
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it is working for you, you are fine and can go ahead.
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If you cannot find this option, it might be that it is always enabled
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and you can continue. It also might mean that the BIOS does not
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provide any emulation support (bad luck here).
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If you find the option and enable it, but the emulation stops working
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soon after the kernel started, then you have bad luck too. You could
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try the "bf2.4" flavor where the root floppy brings USB modules. If
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you are installing with floppy disks, you would need the keyboard once
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before the USB modules can be loaded. Specifying the "keytimer" option
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at boot prompt may help in this case.
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Sometimes, the emulation hangs but it wakes up after few minutes, so
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you could wait some time and try to continue. To fix this behavior,
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you could load Linux' own drivers for USB keyboards. For this, use
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"modconf" (Step "Configure Device Driver Modules") and load usb-uhci
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<sect3><title>More than 64 MB RAM</title>
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The Linux Kernel can not always detect what amount of RAM you have. If
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this is the case please look at <xref linkend="boot-parms"/>.