Function 440Dh /61h     Read Track on Logical Drive                  DOS 3.2+

    Reads data from a track on the specified device and places the
    data in memory.

        Entry   AX    = 440Dh
                BX    = Drive number (0 = default, 1 = A, etc.)
                CH    = 08h (device category, must be 8)
                CL    = 61h
                DS:DX = Pointer to an RWBlock structure

        Return  Input buffer updated
                or
                AX = Error code, if CF is set
                     | 01h Invalid function
                     | 02h File not found
                     | 05h Access denied

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    The RWBlock structure contains information that specifies the
    sectors to be read from and the address of the input buffer.
                                                     
    This function returns an error value of 2 (file not found) if the
    specified drive number is invalid.

    Unlike Int 25h, this function can read hidden sectors.