​KembaraXtra-Computer Terms – boot drive:
A boot drive is the storage device that a computer’s BIOS checks first when loading the operating system during startup. It is the drive from which the system attempts to boot automatically when the computer is powered on.
In older PC systems, the default boot drive was typically the floppy disk drive (A:). If no bootable disk was found there, the system would then check the primary hard disk (C:). The order in which drives are checked can usually be changed through the BIOS setup.