A live USB is a USB flash drive or external hard disk drive containing a full operating system that can be booted. 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.
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. Intel-based Macs carried this functionality over with booting macOS from USB. Specialized USB-based booting was proposed by IBM in 2004 with Reincarnating PCs with Portable SoulPads and Boot GNU/Linux from a FireWire device.
Benefits and limitations
Live USBs share many of the benefits and limitations of live CDs, and also incorporate their own.
First check to see which 15-inch MacBook Pro you have. Choose About This Mac from the Apple menu ( ) in the upper-left corner of your screen. Confirm your model is 'MacBook Pro (Retina, 15-inch, Mid 2015).' If you have that model, enter your computer's serial number below to see if it is eligible for this program. While Apple appears to be committed to the 13.3-inch MacBook Pro for the time being as an entry-level model, having updated it with an M1 Apple silicon chip in November, the high-end 13.3-inch. With Touch ID on your MacBook Pro, you can quickly unlock your Mac and make purchases using your Apple ID and Apple Pay — all with your fingerprint. Learn about Touch ID Find adapters for Thunderbolt 3 (USB‑C) ports. Apple tv app on my macbook pro. MacBook Pro with Apple M1 chip: Testing conducted by Apple in October 2020 using preproduction 13-inch MacBook Pro systems with Apple M1 chip, 8GB of RAM, and 512GB SSD. The wireless web test measures battery life by wirelessly browsing 25 popular websites with display brightness set to 8 clicks from bottom. Testing conducted by Apple in October 2019 using preproduction 2.3GHz 8-core Intel Core i9-based 16-inch MacBook Pro systems with 16GB of RAM and 1TB SSD. The wireless web test measures battery life by wirelessly browsing 25 popular websites with display brightness set to 12 clicks from bottom or 75%.
UNetbootin allows you to create bootable Live USB drives for Ubuntu, Fedora, and other Linux distributions without burning a CD. It runs on Windows, Linux, and Mac OS X.
- Getting your Mac to load from a USB drive is fairly straightforward. Insert the USB boot media into an open USB slot. Press the Power button to turn on your Mac (or Restart your Mac if it’s already on). When you hear the startup chime, press and hold the Option key. Holding that key gives you access to OS X’s Startup Manager.
- A user can carry their preferred operating system, applications, configuration, and personal files with them, making it easy to share a single system between multiple users. Live USBs provide the additional benefit of enhanced privacy because users can easily carry the USB device with them or store it in a secure location (e.g.
- In contrast to live CDs, the data contained on the booting device can be changed and additional data stored on the same device. A user can carry their preferred operating system, applications, configuration, and personal files with them, making it easy to share a single system between multiple users.
- Live USBs provide the additional benefit of enhanced privacy because users can easily carry the USB device with them or store it in a secure location (e.g. a safe), reducing the opportunities for others to access their data. On the other hand, a USB device is easily lost or stolen, so data encryption and backup is even more important than with a typical desktop system.
- The absence of moving parts in USB flash devices allows true random access, thereby avoiding the rotational latency and seek time of hard drives or optical media, meaning small programs will start faster from a USB flash drive than from a local hard disk or live CD. However, as USB devices typically achieve lower data transfer rates than internal hard drives, booting from older computers that lack support for USB 2.0 or newer can be very slow.
- LiveUSB OSes like Ubuntu Linux apply all filesystem writes to a casper filesystem overlay (casper-rw) that, once full or out of flash drive space, becomes unusable and the OS ceases to boot.
- USB controllers on add-in cards (e.g. ISA, PCI, and PCI-E) are almost never capable of being booted from, so systems that do not have native USB controllers in their chipset (e.g. such as older ones before USB) likely will be unable to boot from USB even when USB is enabled via such an add-in card.
- Some computers, particularly older ones, may not have a BIOS that supports USB booting. Many which do support USB booting may still be unable to boot the device in question. In these cases a computer can often be 'redirected' to boot from a USB device through use of an initial bootable CD or floppy disk.
- Some Intel-based Macintosh computers have limitations when booting from USB devices – while the Extensible Firmware Interface (EFI) firmware can recognize and boot from USB drives, it can do this only in EFI mode. When the firmware switches to 'legacy' BIOS mode, it no longer recognizes USB drives. Non-Macintosh systems, notably Windows and Linux, may not be typically booted in EFI mode and thus USB booting may be limited to supported hardware and software combinations that can easily be booted via EFI. However, programs like Mac Linux USB Loader can alleviate the difficulties of the task of booting a Linux-live USB on a Mac. This limitation could be fixed by either changing the Apple firmware to include a USB driver in BIOS mode, or changing the operating systems to remove the dependency on the BIOS.
- Due to the additional write cycles that occur on a full-blown installation, the life of the flash drive may be slightly reduced. This doesn't apply to systems particularly designed for live systems which keep all changes in RAM until the user logs off. A write-locked SD card (known as a Live SD, the solid-state counterpart to a live CD) in a USB flash card reader adapter is an effective way to avoid any duty cycles on the flash medium from writes and circumvent this problem. The SD card as a WORM device has an essentially unlimited life. An OS such as Linux can then run from the live USB/SD card and use conventional media for writing, such as magnetic disks, to preserve system changes; .
Various applications exist to create live USBs; examples include Rufus, Fedora Live USB Creator, UNetbootin, WinToUSB, Win32DiskImager, and YUMI, 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 persistentfile 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:
- A USB flash drive needs to be connected to the system, and be detected by it
- One or more partitions may need to be created on the USB flash drive
- The 'bootable' flag must be set on the primary partition on the USB flash drive
- An MBR must be written to the primary partition of the USB flash drive
- The partition must be formatted (most often in FAT32 format, but other file systems can be used too)
- A bootloader must be installed to the partition (most often using syslinux when installing a Linux system)
- A bootloader configuration file (if used) must be written
- The necessary files of the operating system and default applications must be copied to the USB flash drive
- Language and keyboard files (if used) must be written to the USB flash drive
- USB support in the BIOS’s boot menu (although there are ways to get around this; actual use of a CD or DVD can allow the user to choose if the medium can later be written to. Write Once Read Many discs allow certainty that the live system will be clean the next time it is rebooted.)
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.
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.
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 or WinToUSB.
- ^'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.
- ^'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.
- ^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.
- ^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.
- ^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.
- ^'Plop Boot Manager'. February 7, 2012. Retrieved September 25, 2016.
- ^'Use a Floppy to Boot USB Pendrive Linux'. Pen Drive Linux. 2007-11-21. Retrieved September 25, 2016.
- ^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.
- ^'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.
- ^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.
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UNetbootin allows you to create bootable Live USB drives for Ubuntu and other Linux distributions without burning a CD.
You can either let UNetbootin download one of the many distributions supported out-of-the-box for you, or supply your own Linux .iso file.
UNetbootin can create a bootable Live USB drive
It loads distributions either by downloading a ISO (CD image) files for you, or by using an ISO file you've already downloaded.
Select an ISO file or a distribution to download, select a target drive (USB Drive or Hard Disk), then reboot once done. If your USB drive doesn't show up, reformat it as FAT32.
If you used the 'USB Drive' install mode: After rebooting, boot from the USB drive. On PCs, this usually involves pressing a button such as Esc or F12 immediately after you turn on your computer, while on Macs, you should hold the Option key before OSX boots.
If you used the 'Hard Disk' install mode: After rebooting, select the UNetbootin entry from the Windows Boot Menu.
UNetbootin has built-in support for automatically downloading and loading the following distributions, though installing other distributions is also supported:
UNetbootin can also be used to load various system utilities, including:
Installing Other Distributions Using UNetbootin
Mac Os Bootable Pen Drive Usb
Download and run UNetbootin, then select the 'disk image' option and supply it with an ISO (CD image).
UNetbootin doesn't use distribution-specific rules for making your live USB drive, so most Linux ISO files should load correctly using this option. However, not all distributions support booting from USB, and some others require extra boot options or other modifications before they can boot from USB drives, so these ISO files will not work as-is. Also, ISO files for non-Linux operating systems have a different boot mechanism, so don't expect them to work either.
Distribution X isn't on the list of supported distributions, will it work?
» Maybe, see Installing Other Distributions Using UNetbootin.
UNetbootin isn't able to download the distribution, what should I do?
Download the ISO straight from the website, then provide it to UNetbootin via the diskimage option.
My USB stick isn't booting, what should I do?
Reformat the USB drive as FAT32, then use UNetbootin again to put your distribution on the USB stick.
My USB stick/hard drive isn't detected, what should I do?
Reformat the USB drive as FAT32, then use UNetbootin again. If it still isn't showing up, use the targetdrive command line option.
How do I use UNetbootin from the command line?
» See UNetbootin Command Line Options.
How does UNetbootin work, and what does it do?
» See How UNetbootin Works.
» See USB Drive and Hard Disk Install Modes.
Where can I report bugs, submit patches, etc?
First, make sure you are using the latest version available on this website.
» See Github Issues to file a bug report.
» See Github Pull Requests to submit a patch.
Does UNetbootin have any spyware, viruses, trojans, or other malware?
No; though some anti-virus products may raise 'Trojan.generic' warnings due to the auto-uninstall feature, these are false positives. Just make sure you obtain UNetbootin from this site, not some shady third-party source. If you're absolutely paranoid, you can check the source code and compile it yourself.
What translations are available, and how can I use them?
A number of translations are included in the latest UNetbootin release. See the Translations Page for the status of each.
If a translation corresponding to your system's native language has already been included into UNetbootin, it should automatically load the corresponding translation. Alternatively, you can force the language to use via the lang=es command-line option, where you substitute es with the the 2-letter ISO 639-1 code for your language.
Can I help translate?
If you'd like to help translate this website, join the project on Transifex, then edit translations either on this website or on Transifex.
If you'd like to help translate the UNetbootin program itself, please use Launchpad Translations. If you are new to Launchpad, you will first have to join the corresponding Ubuntu Translators group for the language you intend to translate. For information on using the Launchpad Translations system, see the translations help page.
» See UNetbootin Translations
Removal Instructions (Applicable only to Hard Disk installs)
If using Windows, UNetbootin should prompt you to remove it the next time you boot into Windows. Alternatively, you can remove it via Add/Remove Programs in the Control Panel.
If using Linux, re-run the UNetbootin executable (with root priveledges), and press OK when prompted to uninstall.
Removal is only required if you used the 'Hard Drive' installation mode; to remove the bootloader from a USB drive, back up its contents and reformat it.
Uninstalling UNetbootin simply removes the UNetbootin entry from your boot menu; if you installed an operating system to a partition using UNetbootin, removing UNetbootin will not remove the OS.
To manually remove a Linux installation, you will have to restore the Windows bootloader using 'fixmbr' from a recovery CD, and use Parted Magic to delete the Linux partition and expand the Windows partition.
Mac Os Bootable Usb Creator
Where's the source code, and how can I compile or modify it?
Source code is on Github, though you may prefer a tarball of the latest release.
» See Compiling UNetbootin.
» See UNetbootin Command Line Options.
Mac Os Bootable Usb Maker
» See Building a UNetbootin Plugin.
» See Using a UNetbootin Plugin.
» See Building a Custom UNetbootin Version.
» See List of Custom UNetbootin Versions and Plugins.
UNetbootin was created and written by Geza Kovacs (Github: gkovacs, Launchpad: gezakovacs, contact info).
Translators are listed on the translations page.
UNetbootin is licensed under the GNU General Public License (GPL) Version 2 or above. Site materials, documentation, screenshots, and logos are licensed as Creative Commons Attribution-Share-Alike 3.0.