BackTrack 4 Final is out and along with this release come some exciting news, updates, and developments. BackTrack 4 has been a long and steady road, with the release of a beta last year, we decided to hold off on releasing BackTrack 4 Final until it was perfected in every way shape and form.

With this release includes a new kernel, a larger and expanded toolset repository, custom tools that you can only find on BackTrack, and more importantly, fixes to all (well, most..) major bugs that we knew of. This release we received an overwhelming support from the community and we are grateful to everyone that has contributed to the success of this release.

We’ve moved BackTrack to a dedicated home, where you will be able to keep updated with the development status and latest news. Our goal was to finally produce a focused and dedicated security Linux distribution that has its own resources, personnel, and drive that have dedication in making BackTrack better than it has ever been.

When you download BackTrack 4, we hope that you will agree, that this is the best release that has ever been accomplished from the BackTrack team – appropriately codenamed “pwnsauce”.

If you need your modules almost every time when you run Slax, store them in /slax/modules/ directory of your Slax CD or USB disk. This way the module will be automatically activated during boot procedure.

If you wish to use your modules only sometimes, store them in /slax/optional/ directory (or its subdirectories) on Slax CD or USB disk. Every time you need your module, specify it’s name in the load= boot parameter. For example:

boot: slax load=wine,graphics

This can mean: use module /slax/optional/wine.lzm and all the .lzm modules from /slax/optional/graphics/ subdirectory. Requests for non-existing modules or directories are silently ignored. To remove a module, simply delete it from disk or CD.

If you need to use the module after Slax is started

All the methods described above require you to restart Slax every time you wish to add or remove additional modules. A more comfortable way is to manage modules on the fly, while Slax is running. You can either start the Slax Module Manager (located in ‘System’ menu), or you can use ‘activate’ and ‘deactivate’ commands manually. Syntax is following:

activate /path/firefox.lzm
deactivate firefox.lzm

The module will be activated on the fly and the application will look like installed. Then, you will need to start the application by appropriate command, or find it in the KDE menu.

If you are not comfortable using the commands, simply doubleclick your module.lzm in a file manager (for example in konqueror), this will do the trick as well.

persistent changes will be described here: – slax is readonly – usb slax is writable – when you reboot incorrectly, changes may be broke – there is no option to not save changes – there is an option to start slax fresh without changes

Technical details

technical details will be described here

Boot parameters (also known as cheatcodes) are used to affect the booting process of Slax. Some of them are common for all Linuxes, others are specific for Slax only. You can use them to disable desired kind of hardware detection, to start Slax from harddisk, to skip the login prompt and start GUI, etc.

How to use boot parameters

Reboot your computer and wait several seconds until a nice graphical Slax logo appears with a boot menu (it’s there usually for less then 9 seconds). Choose your desired menu entry and hit Tab key, which will allow you to edit the command line. Write your desired boot argument at the end of command line.

List of boot parameters

acpi=off
nohotplug
nopcmcia
noagp

… disable specified hardware autodetection in the case of hangups. Your hardware won’t be detected at all, you’ll have to use “pcimodules” command after logging into Slax and you’ll have to try to modprobe all needed modules from the list manually.

nodma

… disable DMA for all CD-ROMs and disks

noauto

… list harddisks in fstab with ‘noauto’, so you have to mount every disk manually in order to access it

nohd

… don’t mount any harddisks at all

nocd

… don’t mount any cdroms at all during the boot process. This may be useful if you have to wait very long time during Slax startup, when empty CDROMs keeps spinning for many minutes and don’t return the NO MEDIA error immediately.

nosound

… mute sound instead of raising volume to 77%

from=/dev/hda1/Slax.iso
from=path/to/Slax.iso
from=/dev/hda1
from=path/to/Slax/

… load Slax data from different place instead of the boot device. First example will search for Slax.iso, only on hda1. Second example will search for ‘path/to/Slax.iso’ on all devices; the first device containing the path/file is used. Third example expects that the ISO is unpacked to hda1. Fourth example searches through all disks for a directory ‘path/to/Slax’ and expects content of unpacked ISO inthere.

passwd=somepass
passwd=ask

… set root’s password to “somepass”, or ask (with =ask) for a new password during the boot, before starting Slax (don’t worry, the new password won’t be shown at the login screen)

changes=/dev/device
changes=/dev/device/file.dat
changes=/path/
changes=/path/file.dat
changes=/dev/device/path/

… all changes you made in Slax are kept in memory until you reboot. But with this boot parameter, you tell Slax to use different device (or a file or directory) than the memory for storing changes. You can, for example, format your disk partition /dev/hda1 with some Linux filesystem (eg. xfs) and then use changes=/dev/hda1 to store all changes to that disk (it will be stored in ‘changes’ directory on that disk. This way you won’t loose your changes after reboot. If you use a file name instead of device, and the file contains valid filesystem, Slax will mount it as a loop device and will store changes to it. Moreover if you don’t specify the device where the file is stored, Slax will try to find it on all your partitions. If you use a directory, Slax will save changes to it (it will make a ‘changes’ subdirectory inthere). You don’t even need a Linux filesystem on that disk, as the directory will be overlayed by posixovl. This way, you can save your changes even to VFAT or NTFS.

toram
copy2ram

… copy all files (all required and optional modules) to RAM. You’ll need at least 320MB of RAM to do this and boot Slax properly. This will slow down the boot phase but it will speed up Slax!

load=module

… load optional modules from /optional/ directory on the CD. You can use full module name (module.lzm) or you can skip the extension

noload=module
noload=module[1];module[n]

… disable loading of any modules specified. This affects all the modules on Slax CD, including /base and /modules, so using noload=kde will disable loading of all modules with ‘kde’ in the name. It is useful with copy2ram cheatcode, because any un-used module is not copied to ram.

debug

… enable debug mode (and start bash several times during the boot) hit Ctrl+D to continue booting

autoexec=...
autoexec=startx
autoexec=xconf;startx
autoexec=xconf;startx;reboot

… execute specified command(s) instead of Slax login. In this example, skip Slax login prompt and automatically start XWindow system. Use semicolon (;) as command separator. Slax will not reboot automatically after the command(s) finish, so if you’d like to restart, specify ‘reboot’ or ‘poweroff’ as the last command. If you need to use spaces in the commandline, replace them by ~. For example, autoexec=echo~Shutting~power;poweroff will do just like that.

In general, Slax is faster from USB than from CD. You just have to use the right USB key. Older devices (usually for USB version 1.1) are really slow and will make you troubles. Even reading from such devices is slow. Newer devices work just fine with Slax, and those with ‘ReadyBoost’ are the best ones. I’ve seen booting from SanDisk Cruzer in less then 40 seconds to full GUI, with no further slowdowns even during the system operation.

What can make your USB flash key corrupted?

In general, all filesystems are predisposed for data loss in bad situations. If you unplug the USB key from your computer before Slax finishes its shutdown procedures, or if you poweroff the computer while Slax writes something to the device, you may lost data or get the entire filesystem corrupted. FAT filesystem (widely used on almost all USB flash keys, MP3 players and Cameras) is the most vulnerable one. Anyway, if a filesystem gets damaged, it’s not permanent.

As you may know, USB flash keys have individually erasable segments, each of which can be put through a finite number (for example 100 000) of write cycles before becoming unreliable. Conventional file systems like FAT or ext2 were originally designed for magnetic disks and as such rewrite many of their data structures repeatedly in the same place. The damaged segment can’t be recovered. This type of corruption is permanent.

To avoid filesystem damages, always make sure to shutdown or reboot correctly. If you boot Slax from a different device and use the USB key only as a storage medium, always make sure to unmount it properly before unplugging. If you can, use some journaling filesystems (like XFS) instead of FAT or ext2. And always use only devices with support for ‘wear levelling’, designed to distribute the re-writes across the medium, in order to prolong its life.

How to fix a corrupted filesystem?

As mentioned in the previous section, FAT filesystem is the most vulnerable one. If Linux detects a corruption, it will remount it read-only to prevent further damage. To fix the problem, use:

dosfsck -wa /dev/hdb1

Replace hdb1 by your own partition name, of course. If you get an error message that there are differences between boot sector and its backup, don’t worry about that, it’s not any problem. The utility will simply skip that and will continue fixing all the other errors.

At the download page, you can see [md5] links. These point to a page where the particular filename is printed together with a special string called ‘md5 sum’. This is a 32 characters long text, which represents a check sum of the downloaded file.

This checksum is used for several purposes, the most common is to assure your download was not corrupted. When md5sum of your downloaded file is different than the one published at the md5 page, then you can be 100% sure your file is damaged. In that case, try to download it again.

In order to calculate the md5 sum of your downloaded file, use a special software. You may find it on Google, try searching for ‘md5sum.exe’ if you are in Windows.

Slax for USB is a Slax distribution in TAR format, designed to be unpacked to a writable disk. If you don’t know what TAR format is, you may imagine it as a ZIP archive. Extract (unzip) the archive directly to your USB flash key, to an MP3 player or even to a Hard Disk. Most archival programs can extract TAR without any problem. Slax for USB is set to save all changes you make to the boot device (disk), so it will behave like a normally installed operating system.

How to make it bootable

When Slax is unpacked to your device, it will create ‘/boot/’ and ‘/slax/’ directories there. Only one more step is needed to make Slax boot from your USB device or disk: you have to manually navigate to the newly created /boot/ directory and run bootinst.sh script (if you are in Linux) or bootinst.bat script (if you are in Windows).

The method mentioned above will simply install syslinux bootloader to your device’s MBR (master boot record). Syslinux works only on FAT filesystem (which is widely used on most USB flash keys, Cameras and MP3 players). If your device or disk is formated using a different filesystem (it is strongly recommended to use a native Linux filesystem like XFS), you will have to use ‘liloinst.sh’ script instead. Currently, liloinst doesn’t provide the same nice boot menu like syslinux, but this will be implemented soon.

The difference between Slax for CD and Slax for USB

Both the variants are exactly the same. The only difference is in the distribution format. ISO is prepared for people who need a bootable CD. TAR is for people who need to extract the contents to disk. But as mentioned, the Slax inside is completely the same. You don’t need to download Slax for USB if you have the ISO and you know how to extract it’s content. Also, you don’t need to download ISO, if you have tar and you know how to make a bootable CD from it.

Slax for CD is a Slax distribution in ISO format. In fact, the ISO file you download from this site is a complete image of the CD. For that reason, you have to burn it in a special way; it won’t work if you burn the iso just like a regular file. So to burn it properly, start your favourite CD-writing software and find “Burn image” or “Burn CD iso image” option. It could be hidden somewhere in the menu because people usually don’t need to use this option. Sometimes you will need to change the filetype filter to *.* else you won’t be able to see your .iso, as your burning software may look for a different file extension as default. The resulting CD will be bootable, you don’t need to specify that feature separately.

Note: Some archiving programs (for example winrar) could associate the .iso extension for itself, so it may seem like slax.iso would be an compressed archive. But don’t believe this. Don’t unpack the archive! Burn the ISO as described above else you will lose the bootability.

Steps to boot from Slax CD

All new computers support booting from the CD, but almost all of them are looking for the operating system on the harddisk only. Your goal is to force your computer to use the CDROM instead. There are three ways how to do it:

1. The first one is supported on many motherboards. Your computer can allow you to boot from the CD once (only for this time) by pressing a special key (usually F11, F2 or F10) during the memory checks (very soon after the computer’s power on).

2. The second method is to setup your box to permanently look for a boot-CD at first, and try to boot from the harddisk only if no CD is found. Again, you have to press some key during the startup (usually Del key), which will allow you to enter BIOS SETUP. There you can go through some menus and look for “Advanced settings”, “Boot order” or “Boot options”. Set CDROM as a first device and harddisk as a second one.

All the keystrokes mentioned above are usually written at the computer’s display at the time you can press them, or you may find them in the documentation of your motherboard.

3. Third way how to boot from the CD is by starting DOS and using linux.bat program from Slax CD.

The difference between Slax for CD and Slax for USB

Both the variants are exactly the same. The only difference is in the distribution format. ISO is prepared for people who need a bootable CD. TAR is for people who need to extract the contents to disk. But as mentioned, the Slax inside is completely the same. You don’t need to download Slax for USB if you have the ISO and you know how to extract it’s content. Also, you don’t need to download ISO, if you have tar and you know how to make a bootable CD from it.

Slax has participated in development of so called sqlzma patches; the code implements 7-zip compression (LZMA) into squashfs filesystem. Moreover, squashfs evolved by the time and it now supports bigger block sizes than before. The combination of these two enhancements makes Slax one of the best-compressed operating systems in the history.

All Slax modules are much smaller than any other compressed packages available nowadays for all other Linux distributions, while the speed of decompression remains usually faster than reading the full data from disk.

Slax 6 is portable

Thanks to the AUFS filesystem, the read-only part of Slax (system data and modules) is overlayed by a writable filesystem. You can modify all areas of the filesystem in Slax without any restrictions. Your changes to the read-only parts are transparently copied to the writable branch and stored in memory or in a persistent directory on your disk or even flash drive. Slax is designed to autodetect whether it runs from a writable media, and if that is detected, Slax will save all your changes there automatically.

In Slax, you are not limited to just a persistent home directory – the whole root filesystem is fully writable, so we talk about ‘persistent changes’ (rather than about ‘persistent home’, known from other live distributions). You can modify /bin/bash the same way like ~/kderc.

Slax 6 is feature rich

XWindow system, KDE desktop with K-Office, Internet browsing, e-Mail, Instant messaging, CD/DVD burning and ripping, Audio and Video encoding, Multimedia players, all and even more is included in Slax.

Slax 6 is multilingual

There are official releases of Slax in 28 different languages, including Catalan, Croatian, Czech, Danish, Dutch, Estonian, Finnish, French, Galician, German, Greek, Hebrew, Hungarian, Icelandic, Italian, Lithuanian, Norwegian, Nynorsk, Polish, Portuguese, Romanian, Russian, Slovak, Slovenian, Spanish, Swedish and Turkish.