You will need to be completely familiar with the RandomAccessFile class in order to read and write to specific locations in the disk file. I strongly recommend that you read up on this class before starting on this assignment. In particular, you'll need to understand how to use the seek method to move the file pointer to a specific location in the file and then you can read/write at that location.
Once you understand how seek works, all you need to do is compute the byte offset of the object you are tying to access and seek to that location before reading or writing. Remember to count from 0 (not 1)!!
Your file system can support a maximum file size of 8 blocks (8KB). That does NOT mean that every file will be 8KB in size. In most cases, files will be smaller than the max file size. Each "create" request should check whether the disk has sufficient space for the file and if not, return a "not enough space on disk" error message.
Feel free to do so in your file system program. HOWEVER, you should be very careful in what get written out to the disk. Since each inode has space allocated for exactly 8 characters (16 bytes) to hold the file name, you should always write out 8 characters to disk, regardless of the file size. If your file name is shorter, the unused characters should have the '\0' or spaces. Thus, if you use strings, you'll need to make sure exactly 8 characters are written out, regardless of the string length. We recommend that you use character arrays instead of strings if possible.
Most file operations will only touch the superblock (the free block list and the inode). However, the read and write calls need you to actually read and write data from the specified block on disk. In case of write, you can use a dummy buffer (e.g., with all 1s) to write to disk. Remember, what you write out is what should get read in if you use "read" at a later time.
The RandomAccessFile class provides a readInt and writeInt methods to write out 32 bit representations of integers. Similarly, readByte and writeByte allow you to read/write 1 byte at a time, and readChar and writeChar read and write characters.
Important: Do not read and write ascii characters. You need to write binary (bit) representations of everything in the inode (to make sure it fits in the space allocated in the superblock).