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 Soul Pads