Sysresccd-manual-en Booting the CD-ROM

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[edit] Enable the option

In order to allow this CD-ROM to boot, you have to check that your BIOS is configured properly. In the boot order priorities, the CD drive must be shown before your hard disk.

[edit] Choosing boot image

To use SystemRescueCd, just insert the disc in the CD drive, and power on your computer. The logo screen should be displayed. You can start by pressing Enter, but you may choose other options.

If you want to choose the way the CD-ROM will boot, you have to enter this at the prompt: <image> <parameters>. For example rescuecd setkmap=uk docache will let you boot with the default rescuecd image, using a British keyboard, and the CD-ROM will be fully loaded into memory. Look at the possible choices below.

[edit] Possible choices in SystemRescueCd-1.0.x:

  • rescuecd This is the default choice for 32bits systems, with Framebuffer disabled, best choice.
  • altker32 This is an alternative kernel for 32bits systems. Boot with this kernel in case you have problems with rescuecd. altker32 was named vmlinuz2 in versions prior to SystemRescueCd-1.0.0.
  • rescue64 This is the default 64 bits kernel. Use it if you want to chroot to a 64bits linux system installed on your hard disk, or if you have to run 64 bits programs. This kernel is able to boot SystemRescueCd from the cdrom with 32bits programs, and it required a processor with 64bits instructions (amd64 / em64t).
  • altker64 This is an alternative kernel for 64bits systems. Boot with this kernel in case you have problems with rescue64. Only available from SystemRescueCd-1.0.0 and newer.
  • reschd32 root=/dev/xxx Use this boot image if you want to start from a 32bits linux installed on your harddisk on /dev/xxx. You can boot your installed system this way if your boot manager is broken. In SystemRescueCd versions 0.3.6 to 0.3.8 this option was named rescuehd.
  • reschd64 root=/dev/xxx Use this boot image if you want to start from a 64bits linux installed on your harddisk on /dev/xxx. You can boot your installed system this way if your boot manager is broken, and you need a 64bits processor.

[edit] Choosing boot options

Now, you can give boot parameters. There are a lot of parameters you can use. Several options are only available in recent SystemRescueCd versions. Here are the most important options available:

[edit] General boot options

  • setkmap=xx: if you don't want to be asked for the keymap, you can choose which keymap to load automatically. Replace xx with your keymap (for example: setkmap=de for german keyboards)
  • docache: this option is very useful if you need to insert another disc in the CD drive after booting. The CD-ROM will be fully loaded into memory, and you will be able to remove the disc from the drive. The docache option requires 400MB of memory if you want to cache everything (including the bootdisks and isolinux directories). You can add the lowmem option if you have less that 400MB of memory of to prevent these directories to be copied into memory.
  • root=xxx: this option lets you boot an existing linux system. For example, if you have a 64bits linux gentoo installed on /dev/sda6, you can type reschd64 root=/dev/sda6 and Gentoo Linux will be started instead of the system that is on the CD-ROM. It's important to use the reschd32 or the reschd64 boot images instead of any other boot image. Use reschd32 root=/dev/xxx for 32bits systems and reschd64 root=/dev/xxx for 64bits systems in SystemRescueCd-0.4.x.
  • initscript=service:action: This options allows you to automatically start/stop a service at boot time. For instance if you need the samba service to be started, you can boot with the following option: initscript=samba:start. This does the same thing as /etc/init.d/samba start. You can use this option several times with different services. All the action that are supported by an initscript can be used. This option is available with SystemRescueCd-1.0.2 and newer]].

[edit] Hardware, drivers and troubleshooting options

  • nonet: this will disable the network auto detection at startup
  • scandelay=x: pauses x seconds during the startup to allow slow devices to initialize. This is required when you boot an usb device. A delay of only few seconds should be enough.
  • doxdetect: Since version 0.3.5 the auto-configuration is done in X.Org itself, and then mkxf86config is disabled by default. This option forces the system to run the mkxf86config startup script to run the hardware auto-detection from this script. Use this option if you have problems with the graphical environment configuration. This option replaces the option noxdetect that was useful in previous versions.
  • nodetect: prevents the generic hardware auto-detection. Use this option if you have problems with the hardware auto-detection.
  • doload=xxx: forces to load one/several modules at startup (example: doload=3c59x)
  • noload=xxx: prevents the system to load one/several modules at startup (example: noload=3c59x). Use this option if you have a problem when the system loads a particular module at boot time.
  • dostartx: This option will force the system to load the X.Org graphical environment at boot time. You won't have to type startx by hand to get it.
  • forcevesa: Forces X.Org to work with the safe vesa driver instead of the best video driver detected for your video card. Use this option if you cannot get the graphical environment working with the default options.
  • forcevesa=xxx: The startx command will load the Xvesa server instead of Xorg, and Xvesa will use the screen resolution given as parameter (eg: 1024x768, 1280x1024x32). The forcevesa option can take a parameter from SystemRescueCd-1.0.0 and more recent.
  • all-generic-ide: In case of problems related to your hard disk, try to enable this option (eg rescuecd all-generic-ide)
  • acpi-off / noapic / irqpool: use these options if you have any problem when the kernel boots: if it hangs on a driver or if it crashes, ...
  • dodebug: Enables verbose messages in the linuxrc script.
  • lowmem: Prevents non critical things to be loaded into memory (like the sshd and nfsd services)
  • skipmount=/dev/xxx: The system mounts all the storage devices at boot time to find the sysrcd.dat file. You may not want it to mount a device, for instance if your hard disk is broken because it would crash the system. You can just boot with skipmount=/dev/sda1 skipmount=/dev/sda2 if you want SystemRescueCd to ignore these two partitions. This boot option requires SystemRescueCd-1.0.1 or more recent.

[edit] Network auto-configuration and remote access

It's recommended to use SystemRescueCd-1.0.2 or newer if you use these options since the previous versions had important bugs. *dodhcp: Use dodhcp if you have a DHCP server on your network and you want the system to get a dynamic IP address at boot time.

  • ethx=ipaddr/cidr: Sets the static IP address of all the ethernet interfaces found on the system. The /cidr extension is optional. For instance, if you use option ethx=192.168.0.1 on a machine with two ethernet adapters, both eth0 and eth1 will be configured with 192.168.0.1. You can also write something like ethx=10.0.0.1/24 (using the cidr notation) if you don't use the default netmask.
  • eth0=ipaddr/cidr: This option is similar to ethx=ipaddr/cidr but it configures only one interface at a time. Of course, you can use the eth0=ipaddr/cidr option it for all the ethernet interfaces, not just eth0. For instance if you want to configure the network on a server that has two interfaces, you can write something like this: eth0=192.168.10.1/24 eth1=192.168.20.1. This option requires SystemRescueCd-1.0.2 or newer.
  • dns=ipaddr: Sets the static IP address of the DNS nameserver you want to use to resolve the names. For instance dns=192.168.0.254 means that you want to use 192.168.0.254 as the DNS server.
  • gateway=ipaddr: Sets the static IP address of the default route on your network. For instance gateway=192.168.0.254 means that the computer can connect to a computer outside of the local network via 192.168.0.254.
  • rootpass=123456: Sets the root password of the system running on the livecd to 1234. That way you can connect from the network and ssh on the livecd and give 123456 password as the root password.
  • vncserver=x:123456: The vncserver boot option has been introduced in SystemRescueCd-1.0.2. This options forces the system to configure the VNC-server and to start it automatically at boot time. You have to replace x with the number of displays you want, and 123456 with your password The password must be between 5 and 8 characters, else the boot option will be ignored. In other words the vncserver=2:MyPaSsWd option will give you access to two displays (display=0 on tcp/5900 and display=1 on tcp/5901).

[edit] Options provided by the autorun

Here are the autorun options as they are since SystemRescueCd-1.0.0. For more details, please read the chapter about autorun

  • ar_source=xxx: place where the autorun are stored. It may be the root directory of a partition (/dev/sda1), an nfs share (nfs://192.168.1.1:/path/to/scripts), a samba share (smb://192.168.1.1/path/to/scripts), or an http directory (http://192.168.1.1/path/to/scripts).
  • autoruns=[0-9]: comma separated list of the autorun script that have to be run. For instance if you use autoruns=0,2,7 then the following autorun scripts will be executed: autorun0, autorun2, autorun7. Use autoruns=no to disable all the autorun scripts with a number.
  • ar_ignorefail: continue to execute the scripts chain even if a script failed (returned a non-zero status)
  • ar_nodel: do not delete the temporary copy of the autorun scripts located in /var/autorun/tmp after execution
  • ar_disable: completely disable autorun, the simple autorun script will not be executed
  • ar_nowait: do not wait for a keypress after the autorun script have been executed.

[edit] How to change the default boot options

If you often use the same options and don't want to type the option name at boot time, you may create your own personalized SystemRescueCd and edit syslinux.cfg to add your options. It means you will have to follow the instruction and use the sysresccd-custom script to extract the current files of the livecd, edit isolinux.cfg (syslinux.cfg with USB keys), and recreate the ISO image. If you use the network booting via pxe feature, it's easier since you just have to edit pxelinux.cfg/default on your pxe boot server.

[edit] About the kernels provided

Two kinds of kernels are provided with SystemRescueCd-1.0.2:

  • standard-kernels:
    • latest stable version (linux-2.6.24.5 provided in SystemRescueCd-1.0.2)
    • available in both 32bits (rescuecd) and 64bits (rescue64)
    • sources with a lot of drivers updates (supports more hardware)
    • ide and sata hard disk drivers are based on the libsata (all disks are sda, sdb, ...)
    • disk controllers drivers (IDE, SATA, SCSI) are built-in
    • network drivers drivers are built-in (so that network booting via PXE can work)
    • there is no frame buffer support since it could disturb Xorg/Xvesa
  • alternative-kernels:
    • not the latest stable version (linux-2.6.22.19 provided in SystemRescueCd-1.0.2)
    • available in both 32bits (altker32) and 64bits (altker64)
    • sources are close to the vanilla (more stable)
    • ide and sata hard disk drivers are based on the libpata (hda/hdb/hdc for ide and sda/sdb/sdc for sata)
    • disk controllers drivers (IDE, SATA, SCSI) are compiled as module (so that you can use noload-xxx if it hangs)
    • network drivers drivers are built-in (so that network booting via PXE can work)
    • there is a frame buffer support in that kernel

Both 32bits and 64bits kernels are available:

  • 32 bits kernels:
    • rescuecd and altker32 are the two 32bits kernels provided
    • any intel/amd/via based processor should work with the 32bits kernel
    • you can run a 32bits kernels even if you have a processor that supports 64bits instructions (amd64 / em64t)
    • you can work (backup/restore) 64bits programs with a 32bits kernel
    • you cannot chroot on a partition with 64bits programs with a 32bits kernel
    • you can run both Xorg and Xvesa graphical servers with a 32bits kernel (Xvesa should always work, Xorg may fail if the driver for your graphical card is missing or broken)
  • 64 bits kernels:
    • rescue64 and altker64 are the two 64bits kernels provided
    • 64bits kernels will work only if your processor supports amd64 (amd implementation of x86_64) or em64t (intel implementation of x86_64) instruction set
    • you must use a 64bits kernel if you want to chroot to a linux system using 64bits programs.
    • 64bits kernels do not work on IA64 / Itanium processors
    • 64bits kernels can execute 32bits programs since the IA32 instructions support is included in the kernel
    • you cannot use Xvesa with a 64bits kernel, so you can only use the Xorg graphical server. If Xorg fails you cannot use Xvesa instead.

[edit] Booting from the CD-ROM

Once you have pressed "Enter" at the prompt, the system will begin to load. First, if you didn't disable this option, the map for your keyboard will be loaded. You just have to choose the best one for you. Next, the kernel will continue to load, and there will be many boot scripts that are run. The hardware configuration will be autodetected. For example, all kernel modules required for an USB mouse will be loaded automatically. And you will get a shell prompt. You have several linux consoles available. You can change between them by pressing Alt+F1 for the first one, Alt+F2 for the second, ...

[edit] Booting from the network via PXE

It's also possible to boot SystemRescueCd from the network. Since the installation is not obvious, there is a dedicated chapter to network booting via pxe.

[edit] Booting with an old computer

Many old computers cannot boot a CD-ROM. The problem may come from the Bios, from the CD drive, ... If you have such a problem, you can try to create a boot floppy, that allows to to start the system on the CD-ROM. SmartBootManager can do such a boot floppy for you. If you have no floppy, you can install this bootloader on the hard disk too. Using this boot manager is easy. You must download sbminst, and run the installer from Linux. Here is the most common install process: 

./sbminst -t us -d /dev/fd0

[edit] Booting from a Virtual Machine

It's possible to use SystemRescueCd from Windows or Linux with a complete computer emulator, such as VMWare and Virtual PC. You have to declare the ISO image as the virtual CD-ROM drive. In the virtual BIOS, you must ask the computer to boot on the CD-ROM. It's even possible to use the network. The virtual machine will have a new IP address.

[edit] Booting from the Windows partition

It's now possible to install SystemRescueCd on an NTFS / FAT partition used by Windows. It means you don't have to partition your disk, and you can even boot SystemRescueCd if there is no cdrom drive in your computer.

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