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Filesystems are essential components in contemporary computer systems that organize and manage data. Their performance is crucial in various applications, from web servers to data storage systems. This paper helps to pick the suitable filesystem by comparing btrfs with ZFS by considering multiple situations and applications, ranging from sequential and random performance in the most common use cases to extreme use cases like high-performance computing (HPC). It showcases each option's benefits and drawbacks, considering different usage scenarios. The performance of btrfs and ZFS will be evaluated through rigorous testing. They will assess their capabilities in handling huge files, managing numerous small files, and the speed of data read and write across varied usage levels. The analysis indicates no definitive answer; the selection of the optimal filesystem is contingent upon individual data-access requirements. [ABSTRACT FROM AUTHOR]

The dataset consists of records from the NTFS file system and event logs. In this study, we used images of devices from capture the flags competitions focused on the digital forensic of Windows operating systems and user activities. We created timelines of the security incident from the disk images using the Plaso tool, which we then processed and transformed the attributes of the timelines into binary values to simplify the application of data analysis and machine learning methods. The data are divided into 12 different files, and they are saved in CSV format.

The concept of Software Defined Storage (SDS) has become very popular over the last few years. It is used in public, private, and hybrid clouds to store enterprise, private, and other kinds of data. Ceph is an open source software that implements an SDS stack. This article analyzes the data found on storage devices (Object Store Devices (OSDs)) used to store Ceph BlueStore data from a data forensics point of view. The Object Store Device (OSD) data is categorized using the model proposed by Carrier into the five categories file system, content, metadata, file name, and application category. It then describes how the different data can be connected to present useful information about the content of an OSD and presents the implementation of a forensic software tool for OSD analysis based on Ceph 12.2.4 luminous. [ABSTRACT FROM AUTHOR]

Filesystems are essential components in contemporary computer systems that organize and manage data. Their performance is crucial in various applications, from web servers to data storage systems. This paper helps to pick the suitable filesystem by comparing btrfs with ZFS by considering multiple situations and applications, ranging from sequential and random performance in the most common use cases to extreme use cases like high-performance computing (HPC). It showcases each option’s benefits and drawbacks, considering different usage scenarios. The performance of btrfs and ZFS will be evaluated through rigorous testing. They will assess their capabilities in handling huge files, managing numerous small files, and the speed of data read and write across varied usage levels. The analysis indicates no definitive answer; the selection of the optimal filesystem is contingent upon individual data-access requirements.

The article addresses the issues related to stationary video recorders: their types, purpose, principles of functioning, design characteristics, key components installed in these devices. The author analyses the procedure for using the video recordings from the surveillance cameras in court proceedings. He also justifies the need for comprehensive examinations when investigating stationary video recorders and points out the cases when the appointment of an examination is necessary and when a specialist inspection is enough. The paper presents a research sequence for a stationary video recorder as a computer forensics’ object. Possible questions to the expert, methods, and approaches are listed; difficulties arising during the examination are considered. The author analyzes a case study of a stationary video recorder examination from the expert practice of the laboratory of computer forensics of the Russian Federal Centre of Forensic Science of the Russian Ministry of Justice.

Digital data can be manipulated easily, so information related to the timestamp is important in establishing the reliability of the data. The time values for a certain file can be extracted following the analysis of the filesystem metadata or file internals, and the information can be utilized to organize a timeline for a digital investigation. Suppose the reversal of a timestamp is found on a mobile device during this process. In this case, a more detailed analysis is required due to the possibility of anti-forensic activity, but little previous research has investigated the handling and possible manipulation of timestamps on mobile devices. Therefore, in this study, we determine how time values for multimedia files are handled according to the operating system or filesystem on mobile devices. We also discuss five types of timestamps--file created (C), last modified (M), last accessed (A), digitalized (Di), and filename (FN) of multimedia files, and experimented with their operational features across multiple devices such as smartphones and cameras. [ABSTRACT FROM AUTHOR]

Log-structured merge-tree (LSM-Tree)-based key–value stores are attracting attention for their high I/O (Input/Output) performance due to their sequential write characteristics. However, excessive writes caused by compaction shorten the lifespan of the Solid-state Drive (SSD). Therefore, there are several studies aimed at reducing garbage collection overhead by using Zoned Namespace ZNS; SSD in which the host can determine data placement. However, the existing studies have limitations in terms of performance improvement because the lifetime and hotness of key–value data are not considered. Therefore, in this paper, we propose a technique to minimize the space efficiency and garbage collection overhead of SSDs by arranging them according to the characteristics of key–value data. The proposed method was implemented by modifying ZenFS of RocksDB and, according to the result of the performance evaluation, the space efficiency could be improved by up to 75%. [ABSTRACT FROM AUTHOR]

Log-structured merge-tree (LSM-Tree)-based key–value stores are attracting attention for their high I/O (Input/Output) performance due to their sequential write characteristics. However, excessive writes caused by compaction shorten the lifespan of the Solid-state Drive (SSD). Therefore, there are several studies aimed at reducing garbage collection overhead by using Zoned Namespace ZNS; SSD in which the host can determine data placement. However, the existing studies have limitations in terms of performance improvement because the lifetime and hotness of key–value data are not considered. Therefore, in this paper, we propose a technique to minimize the space efficiency and garbage collection overhead of SSDs by arranging them according to the characteristics of key–value data. The proposed method was implemented by modifying ZenFS of RocksDB and, according to the result of the performance evaluation, the space efficiency could be improved by up to 75%.

This work is dedicated to eliminating the overhead required for guaranteeing the storage order in the modern IO stack. The existing block device adopts a prohibitively expensive approach in ensuring the storage order among write requests: interleaving the write requests with Transfer-and-Flush. For exploiting the cache barrier command for flash storage, we overhaul the IO scheduler, the dispatch module, and the filesystem so that these layers are orchestrated to preserve the ordering condition imposed by the application with which the associated data blocks are made durable. The key ingredients of Barrier-Enabled IO stack are Epoch-based IO scheduling, Order-Preserving Dispatch, and Dual-Mode Journaling. Barrier-enabled IO stack can control the storage order without Transfer-and-Flush overhead. We implement the barrier-enabled IO stack in server as well as in mobile platforms. SQLite performance increases by 270% and 75%, in server and in smartphone, respectively. In a server storage, BarrierFS brings as much as by 43 × and by 73× performance gain in MySQL and SQLite, respectively, against EXT4 via relaxing the durability of a transaction. [ABSTRACT FROM AUTHOR]

The Hubble Space Telescope’s Wide Field Camera 3 (WFC3) instrument, comprised of two detectors, UVIS (Ultraviolet-Visible) and IR (Infrared), has been acquiring ~ 50-100 images daily since its installation in 2009. The WFC3 Quicklook project provides a means for instrument analysts to store, calibrate, monitor, and interact with these data through the various Quicklook systems: (1) a ~ 175 TB filesystem, which stores the entire WFC3 archive on disk, (2) a MySQL database, which stores image header data, (3) a Python-based automation platform, which currently executes 22 unique calibration/monitoring scripts, (4) a Python-based code library, which provides system functionality such as logging, downloading tools, database connection objects, and filesystem management, and (5) a Python/Flask-based web interface to the Quicklook system. The Quicklook project has enabled large-scale WFC3 analyses and calibrations, such as the monitoring of the health and stability of the WFC3 instrument, the measurement of ~ 20 million WFC3/UVIS Point Spread Functions (PSFs), the creation of WFC3/IR persistence calibration products, and many others. [ABSTRACT FROM PUBLISHER]

Over the past decade, storage has been the performance bottleneck in I/O-intensive programs such as online transaction processing applications. To alleviate this bottleneck with minimal cost penalty, cost-effective design of a high-performance disk subsystem is of decisive importance in enterprise applications. Data tiering is an efficient way to optimize cost, performance, and reliability in storage servers. With the promising advantages of solid-state drives (SSDs) over hard disk drives (HDDs) such as lower power consumption and higher performance, traditional data tiering techniques should be revisited to use SSDs in a more efficient way. Previously proposed tiering solutions have attempted to enhance performance based on different parameters such as request size or randomness. These solutions, however, are mostly optimized towards one type of I/O workloads and are not applicable to workloads with different characteristics. This paper presents an online data tiering technique at the operating system level with a linear weighted formulation to enhance I/O performance with minimal cost overhead. The proposed technique characterizes the workload access pattern with respect to metadata versus user data, frequency of accesses, random versus sequential accesses, and read versus write accesses. To evaluate the proposed technique, it is implemented on a Linux 3.1.4 equipped with ext2 filesystem. The experimental results over I/O-intensive workloads show that the proposed technique improves performance up to 30 % as compared to the previous techniques while imposing negligible memory overhead to the system. [ABSTRACT FROM AUTHOR]

Transaction support for filesystems has become a common feature in modern operating systems where data atomicity is achieved by writing transactions to the log region in advance. The logging mechanism is appropriate for flash storage devices due to the inherent nature of flash memory. However, the logging schemes inherently create multiple copies of data, leading to a decrease in the bandwidth of storage systems. In this paper, we present a simple and efficient invalidation scheme for multiple copies of data in a common journaling module. We identify two types of duplications, one in which there is an explicit duplication of the journal region and original region with the same data, and the other in which there is an implicit duplication of transaction commit operations. The invalidation of duplicated data reduces internal write and erase operations and garbage collection overhead for flash devices, which would otherwise increases external I/O bandwidth. Experimental results show that the overall performance improves roughly from 5% to 35% with the invalidation scheme for journal transactions. [ABSTRACT FROM AUTHOR]

Thanks to the supply of smartphones, mobile phones have come to store increasingly more personal information of users. To protect users' information, the information stored in mobile phones should not only be managed safety but also be deleted not to allow restoration. In the filesystems that have been applied to existing mobile phones, even when users have deleted information, data are not completely wiped from the storage. Therefore, the data can be easily recovered by using forensics tools. Considering that mobile phones are always exposed to the risk of robberies and loss, this situation can be misused for personal information spill. The present paper points out problems in the methods of data deleting from smartphones, proposes an efficient data deleting method considering mobile device environments with limitations in battery and hardware performance such as smartphones, and analyzes the efficiency of the techniques in relation to the types of filesystems and data formats. [ABSTRACT FROM AUTHOR]

BTRFS is a Linux filesystem that has been adopted as the default filesystem in some popular versions of Linux. It is based on copy-on-write, allowing for efficient snapshots and clones. It uses B-trees as its main on-disk data structure. The design goal is to work well for many use cases and workloads. To this end, much effort has been directed to maintaining even performance as the filesystem ages, rather than trying to support a particular narrow benchmark use-case. Linux filesystems are installed on smartphones as well as enterprise servers. This entails challenges on many different fronts. Scalability. The filesystem must scale in many dimensions: disk space, memory, and CPUs. -- Data integrity. Losing data is not an option, and much effort is expended to safeguard the content. This includes checksums, metadata duplication, and RAID support built into the filesystem. -- Disk diversity. The system should work well with SSDs and hard disks. It is also expected to be able to use an array of different sized disks, which poses challenges to the RAID and striping mechanisms. This article describes the core ideas, data structures, and algorithms of this filesystem. It sheds light on the challenges posed by defragmentation in the presence of snapshots, and the tradeoffs required to maintain even performance in the face of a wide spectrum of workloads. [ABSTRACT FROM AUTHOR]

Abstract: To track movements of objects and people we need to use expensive technologies and complex softwares. Usually these softwares need lots of memory. There are many examples of objects and people of which would be useful to know the precise locations. Something sent via pony express, position of buses in the city, friends’ locations, and so on. Our purpose is to use connectivity of smartphone to share position via gps by using only a filesystem created ad hoc without databases or user space programs. IFHNFS is based on Hixosfs and NFS (Linux kernel). Indexing the most relevant data directly in the fs structure makes the exchange of data Faster and, via NFS, potentially available whenever and whenever. Ad-hoc solutions for Android have been developed in real contexts. The system have been tested on a network of Android OS devices that share data with a Linux server. [Copyright &y& Elsevier]

Abstract: Time information is an important factor in digital forensic investigations. The time information of files obtained under the New Technology File System (NTFS) for Windows is determined by the creation, modification, access, and master file table (MFT) entry modification times and can be changed by user manipulations such as copy, move, and change. The characteristics of changes in time attributes can be used to analyze certain user behaviors related to data transfer and modification. This study analyzes the change in time attributes of files or folders resulting from user manipulations under different Windows operating systems and deduces user behaviors through a procedure based on the analysis results. [Copyright &y& Elsevier]

This paper introduces the design and implementation of pulse oximetry based on MSP430FG439. Based on the analysis of the system requirements, the signal acquisition and signal processing hardware design of the oximeter are completed. The multi-functional blood oxygen detection module with MSP430 as the core is set up. The oximeter has features: a peripheral probe combined with MSP430 MCU is used to signal acquisition and processing, has a good man-machine interface, real-timely displays the OLED screen pulse waveform and human blood oxygen heart rate, and detects of finger clip. And according to heart rate and blood oxygen alarm which are integrated by file system-based SDHC memory card, one can run the real-time recording and storage parameters. The design of the oxygen meter can be carried out on the power electronics and embedded experiment design. [ABSTRACT FROM AUTHOR]

In this paper, we introduce Systematic P2P Aided Cache Enhancement or SPACE, a new collaboration scheme among clients in a computer cluster of a high performance computing facility to share their caches with each other. The collaboration is achieved in a distributed manner, and is designed based on peer-to-peer computing model. The objective is to provide (1) a decentralized solution, and (2) a near optimal performance with reasonably low overhead. Simulation results are given to demonstrate the performance of the proposed scheme. In addition, the results show that SPACE evenly distributes work loads among participators, and entirely eliminates any requirement of a central cache manager. [ABSTRACT FROM AUTHOR]

Recently PRAM (Phase-change RAM) is emerging as a promising next generation non-volatile memory device, because it supports fast byte-level access capability and in-place update (no erase-before-program constraint) unlike traditional NAND Flash. Although this PRAM technology is not matured yet, in terms of capacity and write performance, we expect that using this PRAM with traditional NAND Flash enables us to design high-performance and low cost storage for consumer electronics. So in this paper, we introduce a PRAM and NAND hybrid storage design as a practical approach. To this end, we first define a hybrid storage architecture, and then design a hybrid FTL (Flash Translation Layer) and a hybrid FAT filesystem. Finally, we demonstrate that our proposed hybrid storage solution enhances the storage performance 6 times faster and lifetime 6.4 times longer, on the average. [ABSTRACT FROM AUTHOR]