MYFS : AN ENHANCED FILE SYSTEM FOR MINIX

Abstract

In this dissertation, design and implementation of an enhanced MINIX file system MyFS for MINIX operating system has been proposed and implemented. This design is for MINIX operating system and MyFS is modified version of MINIX file system with some new features, like append-only, immutable files/directories and secure deletion. MINIX file system has some limitations. MyFS, is an effort to enhance the existing MINIX file system, and also include some new features. In MINIX file system maximum file size is restricted to nearly 65 MB. MyFS lift this restriction and is capable to handle the files of large size. The maximum file size limit is extended to 4GB nearly. MyFS uses the triple indirect blocks to implement support for large files, which have not been used in existing MINIX file system. Two new types of file and directory have been added; append-only and immutable files/directories. These new type of files have are being provided in many modern operating systems, and have been proved very useful to store sensitive system and configuration information. Another new feature of secure file deletion has been added. File systems just delete the references of the file and leave the file data undeleted, which can be recovered by recovery software. Moreover some special techniques can recover the data after overwriting. [5] To securely delete the user data from the disk some specific data patterns are to be write on the disk data blocks.[5] Secure deletion feature tries to delete user file data by overwriting such patterns on the disk. This dissertation is focusing on the design and implementation of these modifications. This design does not propose a new file system from the scratch but suggest modification for enhancement in the existing MINIX file system.