INT 68 - APPC/PC - NETWORK DEVICE CONTROL - DETACH PHYSICAL UNIT
        AH = 01h subfn 2700h
        DS:DX -> control block
Return: control block updated
SeeAlso: AH=01h/SF=2000h,AH=01h/SF=2100h,AH=01h/SF=2200h

Format of control block:
Offset  Size    Description
 00h 12 BYTEs   reserved
 0Ch    WORD    2700h (verb "Detach Physical Unit")
 0Eh  6 BYTEs   00h
 14h    DWORD   (big-endian) return code (see AH=01h/SF=1B00h)
 18h    BYTE    00h  type: hard
                01h  type: soft

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