How to access specific raw data on disk from java

Question

I\'m trying to use the following code to access one byte with offset of 50 bytes in a raw disk.

randomAccessFile = new RandomAccessFile(\"C:\", \"r\");
rando         


        

Answer 1

If you are interested in writing to a raw volume under Windows, try this (needs Java 7).

  String pathname;
  // Full drive:
  // pathname = "\\\\.\\PhysicalDrive0";
  // A partition (also works if windows doesn't recognize it):
  pathname = "\\\\.\\GLOBALROOT\\ArcName\\multi(0)disk(0)rdisk(0)partition(5)";

  Path diskRoot = ( new File( pathname ) ).toPath();

  FileChannel fc = FileChannel.open( diskRoot, StandardOpenOption.READ,
        StandardOpenOption.WRITE );

  ByteBuffer bb = ByteBuffer.allocate( 4096 );

  fc.position( 4096 );
  fc.read( bb );
  fc.position( 4096 );
  fc.write( bb );

  fc.close();

Of course, you have to make sure the device is writable and not accessed/locked by the system. Also make sure your application runs with the necessary privileges (elevated privileges).

Btw: Using new RandomAccessFile(drive, "rw") doesn't seem to work because Java doesn't open the file handle in a mode which is compatible to raw devices (exception is java.io.FileNotFoundException (The parameter is incorrect)). But reading works fine also with RandomAccessFile.