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.