<p>how can access the binary data file(.DAT). i am using geonames API. can anyone help me? </p>

Assuming you are using C# (from the tag), you can use
```
BinaryReader
```
class
to read binary data. See
How to read and write to a binary file
:
```
```
FileStream fs = File.Open(Environment.CurrentDirectory + @"\settings.bin", FileMode.Open);
BinaryReader reader = new BinaryReader(fs);

long number = reader.ReadInt64();
byte[] bytes = reader.ReadBytes(3);
string s = reader.ReadString();

reader.Close();
fs.Close();

Console.WriteLine(number);
foreach (byte b in bytes)
{
    Console.Write("[{0}]", b);
}
Console.WriteLine();
Console.WriteLine(s);
```
```