Interrupt 21h Function 440Dh Minor Code 6Fh 

Retrieves information about the specified drive.

mov ax, 440Dh            ; generic IOCTL

mov bx, DriveNum         ; see below

mov ch, 8                ; device category

mov cl, 6Fh              ; Get Drive Map Info

mov dx, seg DriveMapInfo ; see below

mov ds, dx

mov dx, offset DriveMapInfo

int 21h

jc  error

Parameters

DriveNum

Drive to obtain information about. This parameter can be 0 for the default drive, 1 for A, 2 for B, and so on.

DriveMapInfo

Address of the DRIVE_MAP_INFOIWK8VO structure that receives information about the specified drive.