Speeding up I/O

[Jhd.Honza]

Hi, I am trying to make a failure-tolerant (to I/O errors) file copy, using code like this:

for (long L = 0; L<sourceStream.Length; L++)
{
   try{sourceStream.Seek(L,SeekOrigin.Begin);}
   catch {//SEEK ERROR}

   try {destStream.Seek(L,SeekOrigin.Begin);}
   catch {//SEEK ERROR}

   int i;
   try {i = sourceStream.ReadByte();}
   catch {i = 0; //SOURCE READ ERROR}

   try {destStream.WriteByte(Convert.ToByte(i));}
   catch {//DEST WRITE ERROR}
}

But this is VERY slow process (~1MB/min), how could I speed it up?