Update README with architecture notes

README

@@ -6,14 +6,54 @@ The source files are licensed under Creative Commons Zero License.
 More information at:	http://creativecommons.org/publicdomain/zero/1.0/
 Full license text at:	http://creativecommons.org/publicdomain/zero/1.0/legalcode
 
+Architecture + Notes
+--------------------
+
+Block Zero = Super block
+Block One = Inode store
+Block Two = Occupied by the initial file that is created as part of the mkfs.
+
+Only a limited number of filesystem objects are supported.
+A file cannot grow beyond one block. ENOSPC will be returned as an error on attempting to do.
+Directories store the children inode number and name in their data blocks.
+Read support is implemented.
+Files and Directories can be created. Support for .create and .mkdir is implemented.
+Basic write support is implemented. Writes may not succeed if done in an offset. Works when you overwrite the entire block.
+Locks are not well thought-out. The current locking scheme works but needs more analysis + code reviews.
+Memory leaks may (will ?) exist.
+
+
+Credits
+--------
+All the source code is written by me (Sankar P) until this point. 
+
+An O_LARGETHANKS to the guidance of VijaiBabu M and Santosh Venugopal. Their excellent talks on filesystems motivated me to implement a file system from the scratch. Without their inspirational speeches, I would not have focussed on filesystems.
+
+A big thanks should go to the kernelnewbies mailing list for helping me with clarifying the nitty-gritties of the linux kernel, especially people like Mulyadi Santosa, Valdis Kletnieks, Manish Katiyar, Rajat Sharma etc.
+
+
+TODO
+-----
+- Check the locks. Remove/Add as necessary.
+- Send for review
+- Make a 1.0 release
+- After the 1.0 release, start with support for extents, which on completion will be 2.0
+- After the 2.0 release, start with journalling support, which on completion will be 3.0
+
+
+How To ?
+--------
+If you are planning to learn filesystems, start from the scratch. You can look from the first commit in this repository and move the way up.
+
+
 To compile:
 ------------
 install linux kernel sources and run make from the checkedout directory.
 
+
 To test:
 ---------
 
-
 psankar@linux-9dni:~/src/simplefs> make
 
 psankar@linux-9dni:~/src/simplefs> dd bs=4096 count=100 if=/dev/zero of=image