struct ARBITER_ALTERNATIVE

typedef struct _ARBITER_ALTERNATIVE
{
     UINT64 Minimum;
     UINT64 Maximum;
     UINT64 Length;
     UINT64 Alignment;
     LONG Priority;
     ULONG Flags;
     PIO_RESOURCE_DESCRIPTOR Descriptor;
     ULONG Reserved[3];
} ARBITER_ALTERNATIVE, *PARBITER_ALTERNATIVE;

Windows Vista Kernel Structures