Puppy Linux, an example of an operating system for live USBs
Puppy Linux, an example of an operating system for live USBs
Ubuntu 8.04 running Firefox, OpenOffice.org and Nautilus

A live USB is a portable USB-attached external data storage device containing a full operating system that can be booted from. The term is reminiscent of USB flash drives but may encompass an external hard disk drive or solid-state drive, though they may be referred to as "live HDD" and "live SSD" respectively. They are the evolutionary next step after live CDs, but with the added benefit of writable storage, allowing customizations to the booted operating system. Live USBs can be used in embedded systems for system administration, data recovery, or test driving, and 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

To repair a computer with booting issues, technicians often use lightweight operating systems on bootable media and a command-line interface. The development of the first live CDs with graphical user interface made it feasible for non-technicians to repair malfunctioning computers. Most Live CDs are Linux-based, and in addition to repairing computers, these would occasionally be used in their own right as operating systems.

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 Linux from a FireWire device.[3][4]

Benefits and limitations

A USB flash drive

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 Universal USB Installer, Rufus, Fedora Live USB Creator, and UNetbootin. There are also software applications available that can be used to create a Multiboot live USB; some examples include YUMI Multiboot Bootable USB Creator[10] and Ventoy. 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 16 MiB (Tiny Core Linux) to a large DVD-sized install (4 gigabytes).

To set up a live USB system for commodity PC hardware, the following steps must be taken:

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 or 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 system’s 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 poor; 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.

Microsoft Windows

Although many live USBs rely on booting an open-source operating system such as Linux, it is possible to create live USBs for Microsoft Windows by using Diskpart[11] or WinToUSB.[12]

See also

References

  1. ^ "USB Info and Benefits of Dual-Channel USB". Apple (published February 20, 2012). September 16, 2003. Archived from the original on May 12, 2013. 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. Archived from the original on May 22, 2016. Retrieved September 25, 2016.
  3. ^ Singer, Michael (August 15, 2005). "IBM brains capture a PC's soul". CNET. CBS Interactive. Archived from the original on September 27, 2016. 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. Archived from the original on September 23, 2016. 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. 2007-11-21. Retrieved September 25, 2016.
  8. ^ knome (December 14, 2013). "MactelSupportTeam/EFI-Boot-Mactel". Ubuntu Community Help Wiki. Canonical Ltd. Archived from the original on March 4, 2016. Retrieved September 25, 2016.
  9. ^ "XFCE minimum install HD". Linux Mint Forums. Archived from the original on September 27, 2016. 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. ^ "YUMI - Multiboot USB Creator | Bootable Pen Drive Linux". www.pendrivelinux.com. Retrieved 2021-12-31.
  11. ^ nnamuhcs. "Create a Bootable USB Flash Drive". docs.microsoft.com. Retrieved 2021-09-15.
  12. ^ Gordon, Whitson. "How to Run a Portable Version of Windows from a USB Drive". Lifehacker. Gawker Media. Archived from the original on September 25, 2016. Retrieved September 25, 2016.