AH = 44h
        AL =
           0 = Get device information (DX)
           1 = Set device information (DL, DH = 0)
               DX BITS =
                 0 = console input device
                 1 = console output device
                 2 = null device
                 3 = clock device
                 5 = binary mode
                 6 = EOF
                 7 = device is character device if set
                     if not, EOF = 0 if channel has been written
                     bits 0-5 are block device number
                12 = network device
                14 = can process control strings (AL=2-5, can only be read)
                15 reserved
           2 = Read CX bytes to DS:DX from BX control chan
           3 = Write CX bytes from DS:DX from BX control chan
           4 = as 2 but for drive BL
           5 = as 3 but for drive BL
               AX = number of bytes transfered
           6 = Get input status
           7 = Get output status
               AX = FFH for ready or 00h for not ready
           8 = Is block device BL changeable? (DOS 3)
               AX = 0 = yes
           9 = Is logical device BL local? (DOS 3)
               DX (attribute word) bit 12 (1000h) = 0 = yes
          10 = Is handle BX local? (DOS 3)
               DX (attribute word) bit 15 (8000h) = 0 = yes
          11 = Change sharing retry count to DX (def 3), (DOS 3.x)
               delay CX (def 1)
          12 = General IOCTL (DOS 3.3 [3.2?])
        BX = file handle (or BL = drive number w/0 = default)
Return: CF = 1 if error
            AX = Error Code
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