USB Linux

This script creates a minimal Ubuntu Linux distro onto a USB drive, or it can create an ISO file. The purpose of this distro is to create an initial Winsync installation medium. The Winsync server scripts will then automatically kick in and begin installing Windows and Winsync with minimal user intervention.

This distro is also used to access machines that have a broken OS. To that end it comes with a LXDE, Ice Weasel, and Filezilla. To save RAM they are not started by default (see $EXTRAS below).

The created distro has several features. The most important of which is it loads completely into RAM. This means that it takes about 30 seconds from POST until you can remove the USB drive from the computer. You will be able to access all the capabilities of the distro without the need for the USB drive. Generally, this will take only a few hundred megabytes of RAM.

To optimize the RAM loading, the distro is kept very minimal. Only packages absolutely needed for to complete its mission are installed. You can install additional packages while the system is running. The available RAM is a limitation though.

Usage

This is basically just a very long bash script. You will probably need to adjust the variable values at the top of the script. After that simply run the script as the root user. Note, this script relies on the underlying OS being Debian Linux or a derivative (i.e. Debian, Ubuntu, Mint, etc).

If you want to install the script to a USB drive, simply provide the device file's name. The script does some error checking to make sure that the provided file is, in fact, a USB block device.

$ sudo ./install-usb /dev/sdc

The script can also create ISO files. I use an ISO of the system so that I can test under VirtualBox, which will not boot from the USB drive. Simply pass in a file path ending in .iso, and the script will do the right thing.

$ sudo ./install-usb some/path/usb.iso

Important Variables

Every computer system is different. With this in mind, the script can be easily configured by simply changing the values of several variables located at the beginning of the script.

• $HTTP_CLIENT_SCRIPT - Installation of client OS's to the hard drive is handled by a separate script. We do not want to recreate the USB drive OS just to update the script. So the process is configured to download the script when tty1 logs in after boot. This variable holds the client installation script URL.
• $EXTRAS - This is a list of extra packages to install beyond the bare minimum system. These packages should make using the system much more convenient.
• $CHROOT - This variable will hold the location of the directory we are going to install the minimal system into. We will later chroot into the environment. The path used does not matter, except be on a partition that has several hundred megabytes of space. For example, /media/chroot, or /home/me/chroot will work fine. The script will empty this directory when it is executed.
• $ISO_BUILD - When creating an ISO file, a temporary filesystem must be created in the host. This is the location where these files will reside. The path used does not matter, except be on a partition that has several hundred megabytes of space. The script will empty this directory when it is executed.
• $ARCH - This variable's value tells us what type of architecture we are going to install, e.g. i386, amd64, etc.
• $CODE_NAME - This variable tells us what version of system we are installing. This is done by providing the adjective in the distro's version code name. Note, this value is case sensitive, always use lower case. For example, "saucy" or "raring".
• $MIRROR - This variable will hold our primary repository. You can use any valid Ubuntu mirror. By default this value uses the main "http://archive.ubuntu.com/ubuntu" mirror.
• $SEC_MIRROR - This variable is the URL of the security updates mirror. The value included in the script actually calculates the value based on the $MIRROR variable's value.
• $KERNEL - This variable holds the name of the kernel package to install.
• $HEADERS - This variable holds the name of the kernel headers package to install. The actual value is calculated from the value based on the $KERNEL variable's value.

Changelog

v2.0

• Removed default files from the script itself. Instead they are now actual files in the def-files directory. This shortened the script up considerably.
• The script now creates ISO files as well as installing onto a USB. This makes testing using VirtualBox easier.
• Switch from Debian to Ubuntu as the installed OS.
• Fixed several bugs.