Correcting Boot Problems

By understanding a bit about the boot process you will, in most cases, be able to overcome any problems you might have installing KNOPPIX. Here are some things you should know:

■ Check boot order — Your computer's BIOS has a particular order in which it looks for bootable operating systems. A typical order would be floppy, CD or DVD, and hard disk. If your computer skips over the KNOPPIX boot disk and boots right from hard disk, make sure that the boot order in the BIOS is set to boot from CD or DVD. To change the BIOS, restart the computer and as it first boots the hardware, enter Setup (quickly) as instructed (usually by pressing F1, F2, or DEL). Look for a selection to change the boot order so that your CD or DVD boots before the hard disk.

■ Add boot options — Instead of just letting the boot process autodetect and configure everything about your hardware, you can add options to the boot prompt that will override what KNOPPIX autoconfiguration might do. Press F2 from the boot prompt to see additional boot options.

Some boot options are available with which you can try to overcome different issues at boot time. KNOPPIX refers to these options as cheat codes. For a more complete list, refer to the file knoppix-cheatcodes.txt, which you'll find in the KNOPPIX directory when you mount the CD or the DVD that comes with this book on any operating system.

■■ . Vjr r r'1"!.; [ Many boot options can be used with different Linux systems. So if you are having trouble n^^msifii&SnEH installing or booting a different Linux distribution, you can try any of these options to see if they work. Instead of the word "knoppix," you will probably use a different word to launch the install or boot process for other distributions (such as "linux" for Fedora systems or "morphix" for Morphix Live-CD, depending on the distribution). See Appendix A for information on how to start each Linux distribution.

When KNOPPIX first begins the boot process, you see the boot screen, with the boot: prompt at the bottom. The following tables provide boot prompt options that can help you get KNOPPIX running the way you like. Table 21-1 shows options to use when you want specific features turned on that may not be turned on by default when you boot.

TABLE 21-1

Boot Options to Select Features

Option

Feature

knoppix lang=??

Choose a specific language/keyboard. Replace ?? with one of the following: cn, de, da, es, fr, it, nl, pl, ru, sk, tr, tw, uk, or us.

knoppix desktop=??

Instead of using the KDE desktop (kde), replace ?? with one of the following window managers: fluxbox, icewm, larswm, twm, wmaker, or xfce.

knoppix blind

Start BrailleTerminal (running without X).

knoppix brltty=type, port.table

Add parameters to use for the Braille device.

knoppix wheelmouse

For a wheel mouse, enable IMPS/2 protocol.

knoppix nowheelmouse

For a regular PS/2 mouse, force PS/2 protocol.

knoppix keyboard=us xkeyboard=us

Assign different keyboard drivers to use with text (shell) and graphical (X) interfaces.

knoppix dma

Turn on DMA acceleration for all IDE drives.

knoppix gmt

Use time that is based on Greenwich Mean Time (GMT). You can use utc instead of gmt to get the same result.

knoppix tz=country/city

Specify a particular time zone, based on country and city.

knoppix noeject

Don't eject the CD after KNOPPIX has stopped.

knoppix noprompt

Don't prompt to remove the CD after KNOPPIX stops.

If there is hardware being improperly detected or configured, you can have KNOPPIX skip over that hardware. Table 21-2 contains options for skipping or turning off various hardware features.

TABLE 21-2

Boot Options to Turn Off or Debug Hardware

Option

Result

knoppix

debug

Run KNOPPIX with verbose kernel messages.

knoppix

atapicd

No SCSI emulation for IDE CD-ROMs.

knoppix

noagp

No detection of an AGP graphics card.

knoppix

noapic

Disable the Advanced Programmable Interrupt Controller (APIC). (This can overcome some problems on SMP computers.)

knoppix

acpi=off

Disable Advanced Configuration and Power Interface (ACPI).

knoppix

noapm

No Advanced Power Management support (APM). (With a working ACPI, APM will be off by default. Only one can be active at a time.)

knoppix

noaudio

No sound support.

knoppix

nodhcp

Don't try to start your network connection automatically via DHCP.

knoppix

fstab

Don't read the fstab file to find file systems to mount or check.

knoppix

firewire

No detection of Firewire devices.

knoppix

nopcmcia

No detection of PCMCIA card slots.

knoppix

noscsi

No detection of SCSI devices.

knoppix

noswap

No detection of swap partitions.

knoppix

nousb

No detection of USB devices.

knoppix

nousb2

Disable extensions for USB 2.0.

knoppix

pnpbios=off

Don't initialize plug-and-play (PnP) in the BIOS.

knoppix

failsafe

Do almost no hardware detection.

Table 21-3 lists options that may help if you are having trouble with your video card. Several of these options are particularly useful if you are having trouble with X on a laptop.

TABLE 21-3

Boot Options to Fix Video Problems

Option

Result

knoppix

screen= ??

Pick X screen resolution. Replace ?? with 640 x 480, 800 x 600, 1024 x 768, 1280 x 1024, or any other resolution supported by your video card.

knoppix

xvrefresh=60

Set vertical refresh rate to 60 Hz for X (or other value as specified by monitor's manual).

knoppix

xhrefresh=80

Set horizontal refresh rate to 80 Hz for X (or other value as specified by monitor's manual).

knoppix

xserver= ??

Replace ?? with XFree86 or XF86_SVGA.

knoppix

xmodule= ??

Select the specific driver to use for your video card. Replace ?? with one of the following: ati, fbdev, i 810, mga, nv, radeon, savage, s3radeon, svga, or i 810.

knoppix

2

Run level 2, text mode only.

knoppix

vga=normal

No-framebuffer mode, but X.

knoppix

fb1280x1024

Use fixed framebuffer graphics (1).

knoppix

fb1024x768

Use fixed framebuffer graphics (2).

knoppix

fb800x600

Use fixed framebuffer graphics (3).

Customizing KNOPPIX

Several boot options exist that tell KNOPPIX to look for a customized home directory or configuration information on hard disk or floppy. See the "Keeping Your KNOPPIX Configuration" section later in this chapter for information on how to both save a customized KNOPPIX configuration and tell KNOPPIX where to look for that customized information at boot time. (Unless they were created from KNOPPIX, most other Linux distributions will not use these boot options.)

Table 21-4 lists options you can use to identify the location of your customized data or tell KNOPPIX to run in ways that will make it perform better. Some of these options are described in detail in sections that follow.

TABLE 21-4

Boot Options to Find Data or Boot Faster

Option

Result

knoppix

myconf=/dev/????

Tells KNOPPIX to run the knoppix.sh script from a particular partition. For example, replace ???? with hda1 (first partition on the first IDE drive) or sda1 (first partition on the USB flash drive or SCSI drive).

knoppix

myconf=scan

Search available drives for the knoppix.sh script.

knoppix

home=/mnt/????/filename.img

Identify the location of an image file that should be mounted and used as the / home directory during your KNOPPIX session. For example, using the file /mnt/hda1/knoppix. img gets an image file (knoppix.img) from the top-level directory of the first partition of the first IDE drive.

knoppix

home-scan

Search available drives for a home directory image.

knoppix

mem= ???M

Make the specified amount of memory available to KNOPPIX (for example, 128M).

knoppix

toram

Copy the contents of the CD to RAM and run it from there. (For a live CD, you should have at least 1GB of RAM available to use toram.)

knoppix

tohd=/dev/????

Copy the contents of the CD to a hard disk partition and run it from there. Replace ???? with the device name, such as hda1 or sda1. The partition must be ext2 or VFAT to use this feature.

knoppix

fromhd

Look for KNOPPIX to run on the hard disk, instead of the CD.

knoppix

fromhd=/dev/????

Look for KNOPPIX to run from a particular partition on the hard disk, instead of the CD. Replace ???? with the device name, such as hda1 or sda1.

knoppix

bootfrom=/dev/????

If the KNOPPIX image is on an NTFS or ReiserFS file system, use this option to boot the image from there.

knoppix

bootfrom=/dev/????/KNX.iso

Select a particular image name to boot from, when the image exists on an NTFS or ReiserFS file system on the selected hard disk. The kernel versions on the CD and hard disk image must match.

Special Features and Workarounds

Other boot options are described in the knoppix-cheatcodes.txt file that comes on the KNOPPIX CD (open the KNOPPIX folder from the KNOPPIX icon on the desktop to find the file). Things you can do with boot options include changing the splash screen when KNOPPIX boots, running in expert mode so you can load your own drivers, testing your computer's RAM, and trying to overcome special problems with laptop computers.

■ Testing the CD — If you suspect that you have a bad KNOPPIX CD, I recommend running this from the boot prompt:

knoppix tested

If you are still not able to boot KNOPPIX at this point, it might be that your hardware is either not supported or is broken in some way. To further pursue the problem, check out an appropriate forum at www.knoppix.net.

■ Running KNOPPIX from RAM — To improve performance, KNOPPIX offers a way to run the entire KNOPPIX distribution from RAM (provided you have enough available) or install it on your hard disk and run it from there. Provided that you have more than 1GB of RAM, you can run KNOPPIX entirely from RAM (so you can remove the KNOPPIX DVD or CD and use that drive while you run KNOPPIX) by typing the following from the boot prompt:

knoppix toram

■ Installing KNOPPIX to hard disk — You can run KNOPPIX entirely from hard disk if your hard disk is either a FAT or EXT2 file system type and contains at least 800MB of space. To do this, you must know the name of the hard disk partition you are installing on. For example, to use the first partition on the first IDE drive, you would use /dev/hdal. In that case, to copy KNOPPIX to that disk partition, you would type this at the boot prompt:

knoppix tohd=/dev/hda1

You can watch as KNOPPIX is copied to your hard disk partition and then boots automatically from there. The next time you want to boot KNOPPIX, you can boot it from hard disk again by inserting the KNOPPIX medium and typing the following:

knoppix fromhd=/dev/hda1

With KNOPPIX running from your hard disk, you can safely eject your CD or DVD and use the drive for other things (type eject /dev/cdrom). Refer to the knoppix-cheatcodes.txt file for information on other things you can do from the KNOPPIX boot prompt.

Digital Cameras For Beginners

Digital Cameras For Beginners

Although we usually tend to think of the digital camera as the best thing since sliced bread, there are both pros and cons with its use. Nothing is available on the market that does not have both a good and a bad side, but the key is to weigh the good against the bad in order to come up with the best of both worlds.

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