a. Ext2fs
          1.The Second Extended File System (Ext2fs) was designed by Remy Card and Wayne Davison. It was
              implementedby Remy Card and was further enhanced by Stephen Tweedie and Theodore Ts'o.
          2. Ext2fs is an extensible and powerful file system for Linux. It is the most successful file system so far in the Linux
              community.
          3. Extfs was mostly based on the original Minixfs code and implementation. However it removed the original 64MB
              limit on partitions and increased the file size name to 255 characters.
          4. The ext2fs file system has not only the advantages of extfs but also provides a better space allocation management,
              allows the use of special flags for file management, the use of access control lists and is extensible.

    b. Why Undelete?
           1.If a user deletes a file (whose undelete attribute is set) accidentally or if he deletes it and then changes his mind, he
              can recover back his valuable data using undelete.
           2. Let us compare undelete to a tape back up system if one is in place.
           3. A tape back up system usually backs up the system at midnight and so any information added that day cannot be
               recovered. If all work has been done the same day then the tape back up system cannot help at all.
           4. Even if a user can obtain all or part of his erased information from the backup system, it requires some time
               and effort on the part of the system personnel to recover the data. These services may not be immediately available
               to the user and he may need the information right away.
           5. So the undelete command can be of invaluable help to a user.

II.   Undelete in Linux
           a. Currently the undelete flag in Unix can be accessed in Unix using the chattr and the lsattr commands.
           b. The chattr command can be used to change the a file(s) extended attributes. This command can manipulate among
               other attributes the attribute 'u' for file undeletion.
           c. The lsattr command can be used to list a file(s) extended attributes.
           d. As the man page for the chattr command puts it : When a file with the 'u' attribute set is deleted, its contents
               are saved. This allows the user to ask for its undeletion.
           e. This is exactly what we plan to do in this project this semester, provide the undelete feature in the ext2 file system.

III. Project Design
          a. What we’ll do?
                1. This implementation will use the undelete inode. This inode is the reserved inode # 6. This inode can’t have links
                    to it except itself, so it will not be connected to anything in the filesystem. In this way this directory will be
                    hidden from the rest of the system.
                2. We need to create a system call named "lsdel" that bring the list of the files already deleted that is in the
                    undelete directory (inode 6).
                3. We also need another system call named "undelete". This call brings a file already deleted to the "real world".
                    This means that the user can recover the file that was deleted.
          b. Bottlenecks
                1. After some research we discovered that the undelete directory (inode 6) wasn’t implemented in the extended
                    two filesystem. So we have to create it.
                2. We have to implement a special utility to check the user’s permissions before he can see the deleted files in the
                    directory, so he can’t access files that don’t belongs to him.
                3. If the undelete directory is not periodically cleaned, it will eventually fill up. Therefore, we need a way of
                    determining when files should be deleted from the undelete directory.
          c. Division of labor
                1. Given to the nature of this project, we can’t assign specific parts of it to the group members. Therefore, we
                    have to work together. No one can do anything without the knowledge of the others. Otherwise, we would
                    create pandemonium.