Interrupt 21h Function 71AAh Minor Code 0h

Associates a path with a drive letter.

mov ax, 71aah            ; SUBST
mov bh, 0                ; Create Subst
mov bl, DriveNum         ; see below
mov dx, seg PathName     ; see below
mov ds, dx
mov dx, offset PathName
int 21h

jc error

Parameters

DriveNum
Drive to SUBST. This parameter can be 0 for the default drive, 1 for A, 2 for B, and so on.
PathName
Address of path to associate the drive with.

Return Value

Clears the carry flag if successful. Otherwise the function sets the carry flag and returns an error value in the AX register