sealed class _driveInfo
    {
        public readonly string DriveName;
        public readonly long TotalSizeMB;
        public readonly long UsedSizeMB;
        public readonly long FreeSizeMB;
        public readonly long PercentUsed;

        public _driveInfo(string driveName, long totalSizeMB, long usedSizeMB, long freeSizeMB, long percentUsed)
        {
            DriveName = driveName;
            TotalSizeMB = totalSizeMB;
            UsedSizeMB = usedSizeMB;
            FreeSizeMB = freeSizeMB;
            PercentUsed = percentUsed;
        }
    }

    [Microsoft.SqlServer.Server.SqlFunction
        (
            FillRowMethodName = "_f_fill",
            TableDefinition = "Drive nvarchar(3), SizeMb bigint, UsedMb bigint, AvailableMb bigint, UsePct bigint"
        )
    ]
    
    public static IEnumerable fn_fixeddrives()
    {
        foreach (DriveInfo d in DriveInfo.GetDrives())
        {
            if (d.DriveType == DriveType.Fixed && d.IsReady)
            {
                yield return new _driveInfo(d.Name,
                                            (d.TotalSize) / 1048576,
                                            (d.TotalSize - d.TotalFreeSpace) / 1048576,
                                            (d.TotalFreeSpace) / 1048576,
                                            (d.TotalFreeSpace * 100) / d.TotalSize);
            }
        }
    }

    private static void _f_fill(Object o, out string drvName, out long totalsizeMb, out long usedsizeMb, out long freesizeMb, out long pctused)
    {
        _driveInfo dI = (_driveInfo)o;
        drvName = dI.DriveName;
        totalsizeMb = dI.TotalSizeMB;
        usedsizeMb = dI.UsedSizeMB;
        freesizeMb = dI.FreeSizeMB;
        pctused = dI.PercentUsed;
    }