• You can boot SystemRescueCd on a computer which has no CD/DVD drive
• It’s easy to fit a USB stick in your pocket to have it with you all the times
• You can write your own files on the USB stick at any time
• You can create a backstore to preserve your modifications

Unfortunately the installation was not always easy, especially if you want to install it from Windows or if you have old versions of the utilities required for the installation. You either had to boot on the CDRom edition to run an automatic installation program (sysresccd-usbstick) or you had to follow manual instructions if you did not want to burn the ISO image on a media.

SystemRescueCd-1.5.5 comes with new installers for Linux and Windows that make it easy to install SystemRescueCd on a removable device. In other words it will be possible to just download the ISO image and run the installer. They come with up to date copies of the programs required during the installation so that it works even on system where recent versions of these tools are not installed.

If you are running Linux on your computer, you just have to execute the script called “usb_inst.sh” which is stored at the root of the cdrom ISO image. So can simply mount the iso image using “mount -o loop systemrescuecd-x86-x.y.z.iso /mnt/cdrom” (where /mnt/cdrom can be replaced with any empty directory of your system where you want to mount the cdrom image) and then you run “usb_inst.sh” from the mount directory. This script is a modified version of “sysresccd-usbstick” so it can be used with the same options on the command line. By default it runs in the semi-graphical mode where you just have to select the removable device you want to use.

If you are using Windows you will have to download the cdrom ISO image and the installation program. And then you just have to execute the installer and select the ISO image and the USB device you want to use for the installation. The installer can be executed directly from the download directory, there is no need to install files on your hard-disk. This installer has been developed to use the Win32 API directly to produce a very compact program that does not require any external library to run. You have to run the installer as administrator, it’s required to install the bootloader on the removable device. If you run it as a normal user you may have to type an administrator login/password in a dialog box at the end of the installation.

For more details please read the official documentation about installing SystemRescueCd on a USB stick.

The initramfs is the compressed file (initram.igz) which is loaded just after the kernel image. It loads important drivers (disk controller drivers and Ethernet drivers for network boot), it processes many options from the boot command line and it starts the normal system. This new versions is based on udev so that only the appropriate drivers are loaded, which accelerates the boot process. In old versions all supported kernel drivers were loaded in the first stage of the boot process. This new version still support the “doload=mod1,mod2,mod3″ and “noload=mod1,mod2,mod3″ which allows you to force / blacklist kernel modules. It also preserves compatibility with the existing boot options (ethx=ip, dns=ip, gw=ip, dodhcp, netboot=url, root=auto, root=LABEL=xxx, …)

SystemRescueCd-1.5.1 also comes with two important modifications: parted-2.2 has been patched to fix usability problems (”failed to re-read the partition table” error) which was annoying especially in GParted. This release also fixes problems with the intel xorg driver (xf86-video-intel) which makes the graphical environment extremely slow.

The standard kernels (32bit: rescuecd, 64bit: rescue64) are now based on a new configuration in order to provide a better support for hardware especially for disk controller and network drivers (including in the initramfs).

Old SystemRescueCd versions were already able to boot from the network. But the third stage of the boot process (after dhcp and tftp) was based either on http or tftp. These protocols are used to transfer the compressed root filesystem image (sysrcd.dat) to the memory during the boot process. After this file is copied it’s then running entirely from the memory and you can disconnect the network if you want.

The problem with that is that it may take some time to transfer the whole root filesystem image through the network, and you cannot use it on computers which have less than ~ 400 MB of memory since there would not be enough memory to store the root filesystem image and for the programs.

With NFS and NBD the root filesystem is mounted through the network. It means the root filesystem is not stored locally, and then data are transmitted through the network only when necessary. It allows computers with only 256 MB of memory to boot SystemRescueCd from the network. If you want to boot  SystemRescueCd from either NFS or NBD you still need DHCP and TFTP in the first steps of the boot process. NFS or NBD only replaces the third step of the process which makes the root filesystem accessible after the kernel has started.

Even if NFS is more popular that NBD, the latter one must be easier to configure. NBD only requires a single TCP port to work so it’s less hassle than NFS to administrate. NBD is a service that provides a block device on the client side, and which sends a copy of sysrcd.dat on the server side.

You can find more details about network booting SystemRescueCd in the official documentation.

First, the graphical environment has been updated. It’s now based on Xorg-server-1.5.3, which improves the hardware support and comes with new drivers.  The desktop environment is now xfce, because it’s both a very good environment (very comfortable, many settings, …) and it’s very small on the system. Parts of xfce which are not essential and with many dependencies have not been included anyway.

The kernel has been updated to a new version: linux-2.6.29 comes with more drivers, and also it supports the very promising btrfs filesystem (still under heavy development). GParted has been updated to 0.4.5, it improves the dmraid and the  crypt-luks support.

A new fsarchiver version comes with this release. This program can be used to clone filesystems: it supports all the linux filesystems, including ext4 and btrfs. It’s also able to clone ntfs partitions. It can restore filesystems to a partition which is smaller than the original. It also comes with many interesting features: the compression is multi-threaded (interesting on multi-cores cpu), and it supports the very high compression algorithm called lzma (very good ratio and not too slow on quad-cores cpus). All the data are checksummed so it can handle corruptions. Archive files can also be encrypted using a password. The file format has been finalized so next version will be able to use archive created with the current version. This program cannot be considered as stable yet, so you must be careful if you use it on critical data.

Unfortunately it’s not possible to distribute several editions of SystemRescueCd (small/complete, english-only/multilang, …). It would really be too much effort to maintain so many editions. So the policy is to provide only one edition with the most important stuff, and the tools required to customize your disc.

SystemRescueCd-1.1.2 comes with an interesting feature that allows you to remove all the graphical tools with just one command during the customization process. There is a script named sysresccd-cleansys that you can use to remove categories of packages that you don’t want. It was already possible to remove all the development tools (which are required to install and remove packages). Now you can also remove all the graphical tools using sysresccd-cleansys x11tools.

You can find the detailed instructions in the handbook.

You can see messages from users who have been affected by this bug:
http://www.sysresccd.org/forums/viewtopic.php?t=2326

As a consequence, I just released SystemRescueCd-1.1.2 with a fix for that problem. The ISO filesystem is generated by mkisofs from cdrtools, and it works for everybody.

For all these reasons, rsync is bundled with SystemRescueCd. I wrote a new documentation in the handbook to help people to start using rsync: Backup and transfer your data using rsync. This tutorial will tell you why rsync is great, what you can do with it, how to use it, and what are the most interesting options.

A new tutorial has been written to explain how you can compile your own kernel and add it to SystemRescueCd. This can be done from SystemRescueCd itself, so that you don’t need to have another linux system installed on your hard disk. You can also do all the compilation stuff from any other linux system installed on the hard disk, as long as you know what you are doing. This tutorial is based on SystemRecueCd-1.1.0 because this is the first version which comes with the development tools (gcc, make, …) which are required to compile the kernel. So you should not attempt to follow these instructions with an older version.

After the new kernel sources are compiled, it will be necessary to make a customized SystemRescueCd using the compiled kernel image and modules.

The development tools (gcc, automake, autoconf, …) and the Gentoo-Linux package management tools (emerge, equery, …) have been added to recent SystemRescueCd-1.1.0 versions. These tools are required to install new packages since everything is compiled when you install new stuff on Gentoo. With this new programs, the ISO image grew by about 20MiB only because we are using a squash filesystem with the very efficient lzma compression.

Now it’s possible to install new packages with a command such as “emerge gparted” during the customization. You still have to use sysresccd-custom, it’s just an extra step.

Here is the summarized procedure:
1. expand the sysrcd.dat in /mnt/custom
2. mount -o bind /proc /mnt/custom/proc
3. extract a recent gentoo portage in /mnt/custom/files/usr/portage
4. chroot /mnt/custom
5. install new packages using the gentoo commands (emerge yourpkg)
6. umount everything properly
7. clean /usr/portage
8. recreate sysrcd.dat with mksquashfs
9. recreate the iso image

The complete procedure with details and examples can be found in the official handbook.

All feed back is welcome about this new feature. Please, post questions and suggestions in this section of the forums.

Since version 1.0.1, the main filesystem is an unionfs (aufs in recent versions), so changes on system files are allowed and stored in memory. It allows you to change a system file, for instance you can replace a program with your own version. In versions older that 1.0.1, changes to system files were not allowed at all.

Users who wants to keep their changes in the system files can make a customized SystemRescueCd disc. It’s very convenient when you want to add new programs to the system, but it’s not comfortable if you often have to change files in the system. You don’t want to make a new customized version everyday

That’s why SystemRescueCd-1.1.0-beta2 introduces the backing-store feature. A backing-store is a loopback filesystem stored on an USB-stick or on an hard drive, which contains all the files of the system that have been changed. The modifications are saved to the backing-store every time you edit a file, when you create a new directory, or when the system writes or deletes a file for any other reason. As a consequence, it allows you to keep your configuration changes: you can add your bookmarks and extensions to Firefox, and they will still be there when you reboot SystemRescueCd, as long as the same backing-store is loaded.

A backing-store is a mere ext3 loopback filesystem. You can create a new backing store or grow an existing one using sysresccd-backstore from SystemRescueCd. The system automatically loads backing-stores named sysrcd.bs which are saved at the root of a writeable filesystem. In other words, you don’t have to specify any boot option if you create a backing-store in the default location, and the system scans all the hard-disks partitions and usb-sticks at boot time. You can disable this behaviour by adding the following boot option: backstore=off. Unfortunately backing-stores cannot be copied on a cdrom / dvdrom, since discs are mounted read-only, and backing-stores can only be loaded in the early stage of the boot process.

The backing-store file does not have to be on the same partition as sysresccd. It means you can have the main SystemRescueCd files installed on an USB-stick, and you can have a backing-store saved on another USB-stick. Anyway, the most convenient way o use it is to save both the main SystemRescueCd files and the backing-store on the same USB-stick.

Here is how to create and use a backing store:

• boot SystemRescueCd with option “backstore=off”
• mount the writable partition where you want the backing-store to be saved:
  • mkdir /mnt/backstore
  • mount -o rw /dev/sdaX /mnt/backstore
• create the backing-store (you have to specify a size in mega-bytes)
  • sysresccd-backstore create /mnt/backstore/sysrcd.bs 256
• unmount the writeable partition and reboot:
  • cd /root ; umount /mnt/backstore
  • reboot
• when sysresccd starts again, it should automatically mount the backing-store and use it
• you can check that the backing-store file is mounted on /mnt/memory
• you can install Firefox extensions and change any file of the system
• when you reboot sysresccd again, you customizations must still be there

The default place where to save the backing-store is the root of a partition in a file named sysrcd.bs. You are free to save the backing-store in an alternate location or with another name. In that case the file will not be automatically found by SystemRescueCd unless you specify the path using the following boot option: backstore=/path/to/mysysrcd.bs. By default, SystemRescueCd-1.1.0-beta20 and newer scan all removable disks (eg: usb sticks) at boot time. If your backing-store file is on an hard-disk partition, you will have to boot with the option backstore=alldev so that it scans all block devices, not just removable ones. You can specify two options in the same time, for instance  backstore=alldev,/path/to/mysysrcd.bs will search any file named /path/to/mysysrcd.bs on any block device of your computer.

You can also grow an existing backing-store with no data loss:

• boot SystemRescueCd with option “backstore=off”
• mount the writeable partition where you want the backing-store to be saved:
  • mkdir /mnt/backstore
  • mount -o rw /dev/sdaX /mnt/backstore
• use the sysresccd-backstore script and specify the new size in mega-bytes:
  • sysresccd-backstore grow /mnt/backstore/sysrcd.bs 512
• umount the writeable partition and reboot:
  • cd /root ; umount /mnt/backstore
  • reboot