Category: DOS kernel
INT 21 - DOS 4.0+ - GET BOOT DRIVE AX = 3305h Return: DL = boot drive (1=A:,...) Notes: This function does not use any of the DOS-internal stacks and may thus be called at any time. It is directly dispatched from the INT 21h entry point with interrupts disabled. NEC 9800-series PCs always call the boot drive A: and assign the other drive letters sequentially to the other drives in the system this call is supported by OS/2 Warp 3.0, but not earlier versions of OS/2; it is also supported by Novell DOS 7