bootable

Bootable describes media or devices that are capable of starting a computer's operating system or a tool directly from power-on. A bootable medium contains a boot image that the computer's firmware can load to begin execution. In traditional BIOS systems, the firmware reads the first sector of the bootable drive (the boot sector or Master Boot Record) to locate a bootloader, which then loads the operating system kernel and essential files. In UEFI systems, the firmware loads an executable from the EFI System Partition. A medium is bootable if it presents a valid chain of boot instructions and necessary files to the firmware.

Common examples include installation media for Windows or Linux, live operating systems (LiveCD/LiveUSB), or recovery tools. Bootable media are typically created from disk images such as ISO files using specialized tools and then written to USB drives or optical discs. They may be designed to support specific architectures (such as x86_64 or ARM) and partition schemes (MBR or GPT). Modern systems with Secure Boot may require signed bootloaders or compatible settings. Bootable media are widely used for operating system installation, testing, repair, and troubleshooting, or for portable environments that run directly from removable media without a full installation.