Live USB

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A live USB is a USB flash drive containing a full operating system which can be booted from. Live USBs are closely related to Live CDs, and are sometimes used interchangeably. Like Live CDs, Live USBs can be used for system administration, data recovery, or the testing of operating system distributions without committing to a permanent installation on the local hard drive. Many of the smaller Linux distributions can also be used from a USB flash drive.

Contents

[edit] Benefits and limitations

Live USBs share many of the benefits and limitations of Live CDs. One important advantage over Live CDs is the ability to conveniently change the data contained on the booting device. This allows for Live USBs to be used as personal storage, as it allows a user to carry his or her preferred operating system, applications, files and configuration with him or her, making it easy to share a single system between multiple users. Live USBs provide the additional benefit of enhanced privacy, because the user can carry the USB device with her or store it in a secure location (i.e. a safe) reducing the opportunities for others to access her data.

The lack of moving parts in USB flash devices allows for faster seek time than is achievable with hard drives or optical media, meaning small programs will start faster from a USB flash drive than from a local hard drive or a Live CD or Live DVD. However, as USB devices typically achieve lower data transfer rates than internal hard drives, booting from a computer lacking USB 2.0 support can be very slow.

Some computers, particularly older ones, may not have a BIOS that supports USB booting. In this case a computer can often be "redirected" to boot from a USB device through use of a bootable CD or floppy disk.

[edit] History

[edit] Types of Live-USB

[edit] 1. Live-CD Derived

The first type of Live-USB was created by simply taking the ISO image file from a Live-CD distribution and placing it on USB storage device and then making it bootable.

Advantages Disadvantages
  • Simple to install
  • Compressed format allows for many applications in a small storage container.
  • Updating whole image file is as easy as copying in a new one.
  • Base installation can be as small as 50mb.
  • Difficult to update individual applications or install applications not part of the original image.
  • Base install maximum size can be 700MB to 4GB for large installs.
  • Many Live-CDs are not set to write to their own filesystem as a CD is typically read only, thus it can sometimes be difficult to enable a Live USB OS to write to its flash drive.

[edit] 2. Full Install

The second type of Live-USB is closely related to a traditional operating system hard drive install with minor modifications like the elimination of swap partitions and files.

Advantages Disadvantages
  • Updating applications or the whole thing is as easy as the parent distribution used to create it.
  • Full system encryption possible.
  • Easier to customize with the users preferred Window Manager and applications.
  • Base install usually starts at approximately 200MB (although some can be as little as 40MB) and grows as the user adds applications.
  • More complicated to install.

[edit] Examples

[edit] BSD Full Install

[edit] GNU/Linux Live-CD Derived

[edit] GNU/Linux Full Install

  • Feraga.com: Automated Installer and Howtos for installing Debian GNU/Linux onto a USB flash thumbdrive with support for full system encryption (LUKS with UUID labels for partition identification). Base install is under 250MB without GUI applications.
  • Flash Linux: Installation based on Gentoo packages optimized for smaller USB flash media.
  • Gumstick Gentoo: Howto install Gentoo. Base install includes Fluxbox and runs about 750MB.
  • Knopperdisk: A small distribution based on Gentoo but designed to be run from USB pen drives or floppy disks.
  • Linux Mobile System: A distribution based on Fedora, repackaged to save space.
  • NimbleX: A small (200mb) distribution based on Slackware.
  • RUNT Linux: Based on Slackware with a 2.4 kernel and Umsdos filesystem. Designed as a network testing tool for students at North Carolina State University.
  • THLinux: A full 2.6.17.14 Linux install with a static glibc Busybox root file system that fits on a 64MB USB flash thumb drive.

[edit] Macintosh

  • Mac-on-Stick: Launches Mac System 7 from a USB flash drive.

[edit] Microsoft DOS & Windows

[edit] OpenSolaris

  • Belenix: Customized OpenSolaris installs including Live-CD and Live-USB.

[edit] See also

[edit] External links

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