Journaling is a relatively new feature of modern file systems that is not yet exploited by most digital forensic tools. A file system journal caches data to be written to the file system to ensure that it is not lost in the event of a power loss or system malfunction. Analysis of journal data can identify which files were overwritten recently. Indeed, under the right circumstances, analyzing a ...

This thinker observed that all the books no matter how diverse they might be, are made up out of the same elements: the space, the period, the comma, the twenty-two letters of the alphabet. He also alleged the fact which travellers have confirmed: In the vast Library there are no two identical books. From these two incontrovertible premises he deducted that the Library is total and that its she...

Users of some systems are at risk of being compelled to disclose their keys or other private data, and this risk could be mitigated if access control mechanisms supported an element of plausible deniability. However, existing plausible deniability mechanisms, such as the one-time pad, are of rather limited scope. In this paper, we present the steganographic file system. This is a storage mechan...

This paper describes the Viva File System or VIFS, a technique for highperformance file allocation on disks. VIFS uses bitmaps to represent both free blocks on the disk and allocated blocks in each file. Allocation bitmaps provide a very fast method of finding blocks close to the last allocated block in a file. Fragments (partial blocks) are used to store the overflow from the last file block; ...

Modern disks no longer operate in a simple ”failstop” manner, yet commodity operating systems assume they do. We design and implement a parity based approach to improve the robustness of journaling file systems. We modify the existing ext3 file system for data and ordered journaling modes to incorporate parity and call it the ”Parity File System”. Using PFS, we are able to recover from a single...

We describe the design of Episode, TM a highly portable POSIX-compliant le system. Episode is designed to utilize the disk bandwidth e ciently, and to scale well with improvements in disk capacity and speed. It utilizes logging of meta-data to obtain good performance, and to restart quickly after a crash. Episode uses a layered architecture and a generalization of les called containers to imple...

In this report we show how to manage a distributed hierarchical structure representing a file system. This structure is optimistically replicated, each user work on his local replica, and updates are sent to other replica. The different replicas eventually observe same view of file systems. At this stage, conflicts between updates are very common. We claim that conflict resolution should rely a...

The Quantcast File System (QFS) is an efficient alternative to the Hadoop Distributed File System (HDFS). QFS is written in C++, is plugin compatible with Hadoop MapReduce, and offers several efficiency improvements relative to HDFS: 50% disk space savings through erasure coding instead of replication, a resulting doubling of write throughput, a faster name node, support for faster sorting and ...

On the one hand, hierarchical organizations are rigid in the sense that there is only one path to each document. On the other hand, keyword-based search is flexible because many sets of keywords may lead to the same document, but it lacks a navigation mechanism. We present the new paradigm of a logic file system, which integrates navigation and classification, and the possibility of expressive ...