Consistent and timely access to an arbitrarily damaged file system is an important requirement of enterpriseclass systems. Repairing file system inconsistencies is accomplished most simply when file system access is limited to the repair tool. Checking and repairing a file system while it is open for general access present unique challenges. In this paper, we explore these challenges, present o...

Multiple experts, each predicting a potential file successor, improve accuracy of file access predictions and reduce loss due to incorrect prefetches. Each expert consists of files that have previously succeeded the current file along with one expert that predicts no successor is the best choice. By careful updating of the expert weights, file predictions can be made very accurately both on a p...

File systems store data in files and organize these files in directories. Over decades, file systems have evolved to handle increasingly large files: they distribute files across a cluster of machines, they parallelize access to these files, they decouple data access from metadata access, and hence they provide scalable file access for high-performance applications. Sadly, most cluster-wide fil...

File systems store data in files and organize these files in directories. Over decades, file systems have evolved to handle increasingly large files: they distribute files across a cluster of machines, they parallelize access to these files, they decouple data access from metadata access, and hence they provide scalable file access for high-performance applications. Sadly, most cluster-wide fil...

A local disk-based file system, LDFS, is an attractive way to speed up distributed applications. Local file access is much faster than accessing data on remote file servers through the network. LDFS is also scalable, as it does not rely on centralized file servers, and it exploits already existing resources (local disks) to provide storage. However, since individual workstations are less reliab...

I have recently developed dmfs, a Data Migration File System, for NetBSD[1]. This file system is based on the overlay file system, which is discussed in a separate paper[2], and provides kernel support for the data migration system being developed by my research group here at NASA/Ames. The file system utilizes an underlying file store to provide the file backing, and coordinates user and syste...

The Direct Access File System (DAFS) is a new, fast, and lightweight remote file system protocol. DAFS targets the data center by addressing the performance and functional needs of clusters of application servers. We call this the local file sharing environment. File access performance is improved by utilizing Direct Access Transports, such as InfiniBand, Remote Direct Data Placement, and the V...

In this paper, a new compression/encryption scheme is presented. The basic idea of this scheme is to represent a monotonically increasing sequence of integers with a single integer such that the original sequence can be restored perfectly. First, we recognize the binary bit patterns from the input file using Lempel-Ziv incremental parsing algorithm. Then a second pass through the file revises t...

Secure management of file systems of large organizations can present significant challenges to system administrators, in terms of the number of users, shared access to parts of the file system for supporting large software projects, and securing and monitoring critical parts of the file system from intruders. We present interactive visualization tools for monitoring and viewing the complex acce...

The Direct Access File System (DAFS) is a new, fast, and lightweight remote file system protocol. DAFS targets the data center by addressing the performance and functional needs of clusters of application servers. We call this the local file sharing environment. File access performance is improved by utilizing Direct Access Transports, such as InfiniBand, Remote Direct Data Placement, and the V...