public byte[] readCluster(int clusterNum) {
        byte[] bytesOfCluster = new byte[BPB_BytsPerSec];
        int firstByteOfCluster = (clusterNum + firstDataSector - 2) * BPB_BytsPerSec;
        for (int i = firstByteOfCluster; i < firstByteOfCluster + BPB_BytsPerSec; i++) {
            bytesOfCluster[i-firstByteOfCluster] = imageBytes[i];
        }
        return bytesOfCluster;
    }