Live USB

Puppy Linux, an example of an operating system for live USBs.

A live USB is a USB flash drive or external hard disk drive containing a full operating system that can be booted. Although they are closely related to live CDs in that they can be used in embedded systems for system administration, data recovery, or test driving, live USBs can persistently save settings and install software packages on the USB device. Many operating systems including Mac OS 9, macOS, Windows XP Embedded and a large portion of Linux and BSD distributions can run from a USB flash drive, and Windows 8 Enterprise has a feature titled Windows To Go for a similar purpose.

Background

Personal computers introduced USB booting in the early 2000s, with the Macintosh computers introducing the functionality in 1999 beginning with the Power Mac G4 with AGP graphics and the slot-loading iMac G3 models.[1] Intel-based Macs carried this functionality over with booting macOS from USB.[2] Specialized USB-based booting was proposed by IBM in 2004 with Reincarnating PCs with Portable SoulPads and Boot GNU/Linux from a FireWire device.[3][4]

Benefits and limitations

Live USBs share many of the benefits and limitations of live CDs, and also incorporate their own.

Benefits

Limitations

Setup

Various applications exist to create live USBs; examples include the WinToUSB (Windows focused), Win32DiskImager (Windows focused), YUMI – Multiboot USB Creator, WiNToBootic (Windows focused) or Fedora Live USB Creator and UNetbootin and MultiSystem LiveUSB MultiBoot, which works with a variety of distributions. A few Linux distributions and live CDs have ready-made scripts which perform the steps below automatically. In addition, on Knoppix and Ubuntu extra applications can be installed, and a persistent file system can be used to store changes. A base install ranges between as little as 40 MB to as much as 1 GB.

To set up a live USB system for commodity PC hardware, the following steps need to be done:

Knoppix live CDs have a utility that, on boot, allows users to declare their intent to write the operating system's file structures either temporarily, to a RAM disk, or permanently, on disk and flash media to preserve any added configurations and security updates. This can be easier than recreating the USB system but may be moot since many live USB tools are simple to use.

Full installation

An alternative to a live solution is a traditional operating system installation with the elimination of swap partitions. This installation has the advantage of being efficient for the software, as a live installation would still contain software removed from the persistent file due to the operating systems installer still being included with the media. However, a full installation is not without disadvantages; due to the additional write cycles that occur on a full installation, the life of the flash drive may be slightly reduced. To mitigate this, some live systems are designed to store changes in RAM until the user powers down the system, which then writes such changes. Another factor is if the speed of the storage device is destitute; performance can be comparable to legacy computers even on machines with modern parts if the flash drive transfers such speeds. One way to solve this is to use a USB hard drive, as they generally give better performance than flash drives regardless of the connector.

Windows

Although many live USBs rely on booting an open-source operating system such as Linux, it is possible to create live USBs for Windows by using Diskpart or WinToUSB.[10]

Examples of Live USB operating systems

Bootable Windows To Go USB flash drive

Comparison

Distribution Alternatives to live CD creation File saving Application saving Boot methods
Fedora 9 Netinstaller (downloads an ISO image and makes USB), UNetbootin In folder None
Gobolinux Zip + sh and bat scripts N/A N/A 2ram (gobolinux toram)
sidux USB installer GUI In folder, on USB stick Auto Normal
Slax Zip + sh and bat scripts, UNetbootin N/A N/A
SliTaz None and from internal drive ($tazusb) In hacker folder Through script (Tazusb) 2ram – lowram
Ubuntu
and derivatives
UNetbootin Auto Auto
Wolvix None (Control Panel) Auto after making permanent space (Control panel) Auto AllUsb – 2Ram

Syslinux is a common program to make a bootable USB storage device.

See also

  1. Secure Hardware Browser is a (bootable read-only bastion host created to protect users while accessing online banking)
Wikimedia Commons has media related to Live USB.
Wikibooks has a book on the topic of: Live distro and Full Linux Install

References

  1. "USB Info and Benefits of Dual-Channel USB". Apple (published February 20, 2012). September 16, 2003. Retrieved September 25, 2016. Bootable USB drives: A storage device such as a SuperDisk, Zip disk, or other USB storage drive can be used to hold a valid system folder and used at startup.
  2. "Starting from an external USB storage device (Intel-based Macs)". Apple. March 22, 2016. Retrieved September 25, 2016.
  3. Singer, Michael (August 15, 2005). "IBM brains capture a PC's soul". CNET. CBS Interactive. Retrieved September 25, 2016.
  4. Honeyford, Martyn (July 15, 2004). "Boot Linux from a FireWire device". IBM DeveloperWorks. IBM. Archived from the original on January 17, 2007. Retrieved May 15, 2016.
  5. Trevor (May 6, 2010). "Boot From a USB Drive Even if your BIOS Won't Let You". How-To Geek. Retrieved September 25, 2016.
  6. "Plop Boot Manager". February 7, 2012. Retrieved September 25, 2016.
  7. "Use a Floppy to Boot USB Pendrive Linux". Pen Drive Linux. Retrieved September 25, 2016.
  8. knome (December 14, 2013). "MactelSupportTeam/EFI-Boot-Mactel". Ubuntu Community Help Wiki. Canonical Ltd. Retrieved September 25, 2016.
  9. "XFCE minimum install HD". Linux Mint Forums. Retrieved September 25, 2016. Live cd only write to the swap partition if your pc has one.
    If it doesn't it'll only use your RAM.
  10. Gordon, Whitson. "How to Run a Portable Version of Windows from a USB Drive". Lifehacker. Gawker Media. Retrieved September 25, 2016.
  11. dminer (November 1, 2007). "OpenSolaris Developer Preview on USB flash drives". Sun. Archived from the original on August 3, 2009.
  12. "14 – Disk Setup". openbsd.org.
  13. "Create a MiniMe 2008 USB Flash Drive from Windows". Pen Drive Linux. Retrieved September 25, 2016.
  14. Sridharan, Sriram (July 12, 2008). "Installing an Operating System on a USB drive". Orangeman Burns. Archived from the original on March 9, 2009. Retrieved September 25, 2016.
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