Development Of File System Research Articles

The Security War in File Systems: An Empirical Study from A Vulnerability-centric Perspective

This article presents a systematic study on the security of modern file systems, following a vulnerability-centric perspective. Specifically, we collected 377 file system vulnerabilities committed to the CVE database in the past 20 years. We characterize them from four dimensions: why the vulnerabilities appear, how the vulnerabilities can be exploited, what consequences can arise, and how the vulnerabilities are fixed. This way, we build a deep understanding of the attack surfaces faced by file systems, the threats imposed by the attack surfaces, and the good and bad practices in mitigating the attacks in file systems. We envision that our study will bring insights towards the future development of file systems, the enhancement of file system security, and the relevant vulnerability-mitigating solutions.

Prism-SSD: A Flexible Storage Interface for SSDs

The rapid adoption of solid-state drives (SSDs) as a major storage component has been made possible thanks to their ability to export a standard block I/O interface to file system and application developers. Meanwhile, this high-level abstraction has been shown to limit the utilization of the devices and the performance of applications running on top of them. Indeed, many optimizations of performance-critical applications bypass the standard block interface and rely on low-level control over SSD internal processes. However, the need to directly manage the physical device significantly increases development complexity and cost, and reduces its portability. Thus, application developers must choose between two extreme options, either easy development or optimal performance, without a real possibility to balance between these two objectives. To bridge this gap, we propose a flexible storage interface that exports the SSD hardware in three levels of abstraction: as a raw flash media with its low-level details, as a group of functions to manage flash capacity, or as a configurable block device. This multi-level abstraction allows developers to choose the degree in which they desire to control the flash hardware in a manner that best suits the applications’ semantics and performance objectives. We demonstrate the usability of this new model with Prism-SSD—a prototype of this interface as a user-level library on the Open-Channel SSD platform. We use each of the interface’s three abstraction levels to modify the I/O module of three representative applications: a key-value cache system, a user-level file system, and a graph processing engine. Prism-SSD improves application performance by 5% to 27%, at varying development costs, between 200 and 3,500 lines of code.

Spiffy

Many file-system applications such as defragmentation tools, file-system checkers, or data recovery tools, operate at the storage layer. Today, developers of these file-system aware storage applications require detailed knowledge of the file-system format, which requires significant time to learn, often by trial and error, due to insufficient documentation or specification of the format. Furthermore, these applications perform ad-hoc processing of the file-system metadata, leading to bugs and vulnerabilities. We propose Spiffy, an annotation language for specifying the on-disk format of a file system. File-system developers annotate the data structures of a file system, and we use these annotations to generate a library that allows identifying, parsing, and traversing file-system metadata, providing support for both offline and online storage applications. This approach simplifies the development of storage applications that work across different file systems because it reduces the amount of file-system--specific code that needs to be written. We have written annotations for the Linux Ext4, Btrfs, and F2FS file systems, and developed several applications for these file systems, including a type-specific metadata corruptor, a file-system converter, an online storage layer cache that preferentially caches files for certain users, and a runtime file-system checker. Our experiments show that applications built with the Spiffy library for accessing file-system metadata can achieve good performance and are robust against file-system corruption errors.

Frog

This article presents a framework, Frog, for Context-Based File Systems (CBFSs) that aim at simplifying the development of context-based file systems and applications. Unlike existing informed-based context-aware systems, Frog is a unifying informed-based framework that abstracts context-specific solutions as views, allowing applications to make view selections according to application behaviors. The framework can not only eliminate overheads induced by traditional context analysis, but also simplify the interactions between the context-based file systems and applications. Rather than propagating data through solution-specific interfaces, views in Frog can be selected by inserting their names in file path strings. With Frog in place, programmers can migrate an application from one solution to another by switching among views rather than changing programming interfaces. Since the data consistency issues are automatically enforced by the framework, file-system developers can focus their attention on context-specific solutions. We implement two prototypes to demonstrate the strengths and overheads of our design. Inspired by an observation that there are more than 50% of small files (<4KB) in a file system, we create a Bi-context Archiving Virtual File System (BAVFS) that utilizes conservative and aggressive prefetching for the contexts of random and sequential reads. To improve the performance of random read-and-write operations, the Bi-context Hybrid Virtual File System (BHVFS) combines the update-in-place and update-out-of-place solutions for read-intensive and write-intensive contexts. Our experimental results show that the benefits of Frog-based CBFSs outweigh the overheads introduced by integrating multiple context-specific solutions.

Application of Machine Vision in ARM Based on OpenCV and Qt

Based on the research of Linux kernel file system and embeded development environment, to build the Linux root file system from the bottom, to complete the development environment of Qt and Opencv dynamic library transplantation, through the efficient development platform and streamlined building the file system, realize the use of fewer resources to complete the application of machine vision in the ARM development board, make contributions to the future development of intelligent mobile terminal.

A Study of Linux File System Evolution

We conduct a comprehensive study of file-system code evolution. By analyzing eight years of Linux file-system changes across 5079 patches, we derive numerous new (and sometimes surprising) insights into the file-system development process; our results should be useful for both the development of file systems themselves as well as the improvement of bug-finding tools.

A Cloud Computing Architectural Model Based on Virtual Machine Pool

Cloud computing is a new-type of computing model. This paper deeply expounded the key technology of virtualization and cloud computing through theoretical analysis and practice research on cloud computing and its architecture. Then, it proposed a common cloud computing architecture model based on virtual environment, which consisted of layers of data center, cloud file system, computing model, data management, and application development. In addition, it realized a cloud computing platform based on Hadoop.

File system virtual appliances

File system virtual appliances (FSVAs) address the portability headaches that plague file system (FS) developers. By packaging their FS implementation in a virtual machine (VM), separate from the VM that runs user applications, they can avoid the need to port the file system to each operating system (OS) and OS version. A small FS-agnostic proxy, maintained by the core OS developers, connects the FSVA to whatever OS the user chooses. This article describes an FSVA design that maintains FS semantics for unmodified FS implementations and provides desired OS and virtualization features, such as a unified buffer cache and VM migration. Evaluation of prototype FSVA implementations in Linux and NetBSD, using Xen as the virtual machine manager (VMM), demonstrates that the FSVA architecture is efficient, FS-agnostic, and able to insulate file system implementations from OS differences that would otherwise require explicit porting.

On incremental file system development

Developing file systems from scratch is difficult and error prone. Using layered, or stackable, file systems is a powerful technique to incrementally extend the functionality of existing file systems on commodity OSes at runtime. In this article, we analyze the evolution of layering from historical models to what is found in four different present day commodity OSes: Solaris, FreeBSD, Linux, and Microsoft Windows. We classify layered file systems into five types based on their functionality and identify the requirements that each class imposes on the OS. We then present five major design issues that we encountered during our experience of developing over twenty layered file systems on four OSes. We discuss how we have addressed each of these issues on current OSes, and present insights into useful OS and VFS features that would provide future developers more versatile solutions for incremental file system development.

FIST

Traditional file system development is difficult. Stackable file systems promise to ease the development of file systems by offering a mechanism for incremental development. Unfortunately, existing methods often require writing complex low-level kernel code that is specific to a single operating system platform and also difficult to port. We propose a new language, FiST, to describe stackable file systems. FiST uses operations common to file system interfaces. From a single description, FiST’s compiler produces file system modules for multiple platforms. The generated code handles many kernel details, freeing developers to concentrate on the main issues of their file systems. This paper describes the design, implementation, and evaluation of FiST. We extended file system functionality in a portable way without changing existing kernels. We built several file systems using FiST on Solaris, FreeBSD, and Linux. Our experiences with these examples shows the following benefits of FiST: average code size over other stackable file systems is reduced ten times; average development time is reduced seven times; performance overhead of stacking is 1–2%.

Lessons from characterizing the input/output behavior of parallel scientific applications

As both processor and interprocessor communication hardware is evolving rapidly with only moderate improvements to file system performance in parallel systems, it is becoming increasingly difficult to provide sufficient input/output (I/O) performance to parallel applications. I/O hardware and file system parallelism are the key to bridging this performance gap. Prerequisite to the development of efficient parallel file systems is the detailed characterization of the I/O demands of parallel applications. In the paper, we present a comparative study of parallel I/O access patterns, commonly found in I/O intensive scientific applications. The Pablo performance analysis tool and its I/O extensions is a valuable resource in capturing and analyzing the I/O access attributes and their interactions with extant parallel I/O systems. This analysis is instrumental in guiding the development of new application programming interfaces (APIs) for parallel file systems and effective file system policies that respond to complex application I/O requirements.

Parallel file systems for the IBM SP computers

Parallel computer architectures require innovative software solutions to utilize their capabilities. This statement is true for system software no less than for application programs. File system development for the IBM SP product line of computers started with the Vesta research project, which introduced the ideas of parallel access to partitioned files. This technology was then integrated with a conventional Advanced Interactive Executive™ (AIX™) environment to create the IBM AIX Parallel I/O File System product. We describe the design and implementation of Vesta, including user interfaces and enhancements to the control environment needed to run the system. Changes to the basic design that were made as part of the AIX Parallel I/O File System are identified and justified.

File-system development with stackable layers

Filing services have experienced a number of innovations in recent years, but many of these promising ideas have failed to enter into broad use. One reason is that current filing environments present several barriers to new development. For example, file systems today typically stand alone instead of building on the work of others, and support of new filing services often requires changes that invalidate existing work. Stackable file-system design addresses these issues in several ways. Complex filing services are constructed from layer “building blocks,” each of which may be provided by independent parties. There are no syntactic constraints to layer order, and layers can occupy different address spaces, allowing very flexible layer configuration. Independent layer evolution and development are supported by an extensible interface bounding each layer. This paper discusses stackable layering in detail and presents design techniques it enables. We describe an implementation providing these facilities that exhibits very high performance. By lowering barriers to new filing design, stackable layering offers the potential of broad third-party file-system development not feasible today.

240. DF 用リアルタイムディジタル・ファイルシステムの開発(DSA 装置他)

240. DF 用リアルタイムディジタル・ファイルシステムの開発(DSA 装置他)

240. DF 用リアルタイムディジタル・ファイルシステムの開発(第 46 回総会学術大会会員研究発表予稿)

240. DF 用リアルタイムディジタル・ファイルシステムの開発(第 46 回総会学術大会会員研究発表予稿)

Automated Periodical Systems at Dundee University Library

A description is given of the development and present state of the in-house periodicals housekeeping file and binding systems. An automated public catalogue of periodicals was first made possible by the Library's participation in the Scottish Libraries Co-operative Automation Project. Later the catalogue was transferred to the Geac system.