Bootable Computer Doctor

The Story

A live distribution is a Linux distribution you can run from a pen drive or CDROM drive, without having to first install it onto your hard drive. This is where the name “live” comes from, as it can be run “live without installation”.

Many times I use some Live CD to run diagnostics, recover a corrupted boot sector, reset the password for a Windows/Linux machine and many other similar tasks provided by live distributions.

You get very useful Live distributions these days. They are most often configured for either CD/DVD or USB pendrive, though some of the smarter ones can use the same image to boot from either. Beyond this, when you boot from them you will (mostly) get a syslinux bootloader screen from which you select what you want to boot.

Here are a few very useful example live distros that I use:

1. SystemRescueCd
2. Ultimate Boot CD
3. Trinity Rescue Kit
4. Puppy Linux
5. DamnSmallLinux
6. Pentoo Linux

So if I just wanted to reset the password for a Windows machine, I would burn a CD from the Ultimate Boot CD image and boot from it. In then has an option for booting ntpasswd, which allows editing of the Windows registry and resetting an account’s password.

In another scenario if I just wanted to reinstall Grub, my Linux bootloader, I would boot DamnSmallLinux to get a terminal from which I can reconfigure my boot loader.

The problem is that depending on what I need to do I might need a different Live distribution every time. I used to carry CDs for each of these, but I would forget a CD in the drive, and sometimes I don’t have my CDs with me, or the machine doesn’t have a CDROM drive. The ideal situation would be to have all of this on a USB pen drive which I carry with me all the time anyway.

So after investigating this, it turned out that in themselves the distros don’t like sharing their boot drive with others. Some of them didn’t even support booting from Pen drives (only CDROMS).

Open Source DIY

Being open source all these problems are just hurdles to overcome. Nothing more.

I downloaded all of them, and one by one extracted their images into a directory structure of my choice. To ensure they don’t polute the root directory of my pen drive I put them all into a syslinux subdirectory. This alone will break some of them since these want their files in the root of the filesystem. Again, just something to hack out.

After this I made my own syslinux bootloader configuration, which has a main menu with an item for each of the distros. If you select one of these items, it’s original menu will be loaded. I also modified their menus to create an item that will return back to my main menu.

On top of the structure of the menus I had to modify the actual boot loader configurations to support my new directory structure as well.

Further, to speed up the development of this I made a mirror image of the whole pen drive into a file, and then used this for developing my distro collection. For testing I would boot the image with QEMU. All this allowed many extra abilities like to back it up, boot multiple instances and easily revert to previous versions.

Once I had all of the boot menus and boot loaders configured correctly, all that was left was to actually test all the images and make sure they loaded correctly. This required making some more modifications of the distro’s own init scripts (since they either didn’t support pen drives or because I change the directory structure they were expecting)

Zeta, the conclusion

In the end I had a bootable pen drive with 6 different live distributions on it, some with both 32bit and 64bit versions available.

I named it Zeta, the sixth letter of the Greek alphabet – which has a value of 7. The intention was to add a 7th distribution. I left open some space for it and will be adding it in the near future (as soon as I’ve decided on which one to add). In the meantime there are 6 other very useful distributions.

Drop me a message if you want the image and instructions for installing it onto your own pendrive.

Here are a few screen shots of my resulting work:

So Why Love Linux? Because within hours I was able to make a “computer doctor” pendrive distribution.