This article proposes an approach to estimate performance baseline of file system operations for selection of optimal file system and precise optimization of file system operations for Linux-based edge devices in Industry 4.0. To demonstrate this approach, we discuss the design and implementation of an ideal-but-hypothetical file system, namely,ufs. We evaluate the performance ofufsto set the optimal lower bound on the cost of file system operations. We then evaluate and compare the performance of Linux extended file systems with the estimated baseline set byufsto identify the file system that closely approximatesufs. Our findings suggest that graceful aging, warm caches, and readahead significantly help extended file systems approximate the estimated baseline while ext4 file system closely approximates baseline performance even during aging.

Purpose The purpose of this paper is to investigate the private-data pertaining to the interaction of users with social media applications that can be recovered from second-hand Android devices. Design/methodology/approach This study uses a black-box testing-principles based methodology to develop use-cases that simulate real-world case-scenarios of the activities performed by the users on the social media application. The authors executed these use-cases in a controlled experiment and examined the Android smartphone to recover the private-data pertaining to these use-cases. Findings The results suggest that the social media data recovered from Android devices can reveal a complete timeline of activities performed by the user, identify all the videos watched, uploaded, shared and deleted by the user, disclose the username and user-id of the user, unveil the email addresses used by the user to download the application and share the videos with other users and expose the social network of the user on the platform. Forensic investigators may find this data helpful in investigating crimes such as cyber bullying, racism, blasphemy, vehicle thefts, road accidents and so on. However, this data-breach in Android devices is a threat to user's privacy, identity and profiling in second-hand market. Practical implications Perceived notion of data sanitisation as a result of application removal and factory-reset can have serious implications. Though being helpful to forensic investigators, it leaves the user vulnerable to privacy breach, identity theft, profiling and social network revealing in second-hand market. At the same time, users' sensitivity towards data-breach might compel users to refrain from selling their Android devices in second-hand market and hamper device recycling. Originality/value This study attempts to bridge the literature gap in social media data-breach in second-hand Android devices by experimentally determining the extent of the breach. The findings of this study can help digital forensic investigators in solving crimes such as vehicle theft, road accidents, cybercrimes and so on. It can assist smartphone users to decide whether to sell their smartphones in a second-hand market, and at the same time encourage developers and researchers to design methods of social media data sanitisation.

As a consequence of voluminous growth and proliferation of digital data, the file system size and count limitations have become problematic. The fact is that file systems use fixed length fields within their metadata structures to keep track of volume size, file size and file count, and hence need design (and source) modification to cope up with this growth. In this paper, we propose a Scalable User-space Virtual File System, namely suvfs, which when mounted on top of any file system extends its capability to store and process large files not natively supported by the file system. It works by exploiting the concept of virtual unification to present a large virtual file that spans over a number of legitimate sized physical files. It does so without modifying user applications, system libraries, system calls and even file systems. We implemented it using FUSE framework & evaluated it for performance overhead added by layering it over FAT32 file system. The results indicate that there is a very minimal performance hit encountered by FAT32 with suvfs mounted on top for sequential reading, while as for sequential writing & deletion the performance hit increases with file size but is largely due to FUSE framework & not by suvfs.

Nowadays security systems have become highly sophisticated. However, breaches are inevitable. Nevertheless, post-breach analysis is performed to assess the severity of the breach and to trace the intruder's actions. This paper proposes drWatson, a layered file system that in case of an illegitimate file system access provides data for post-breach analysis to assess the severity of the breach and to trace the intruder's actions. drWatson, when mounted on top of any concrete file system, works by logging all the operations along with their date time stamps targeted to the below mounted file system.