Joseph P. Kaylor

A Virtual Computing Laboratory

Many institutions choose to do periodic imaging of computers, which is both painstaking and limiting in terms of keeping software up to date. The authors describe an approach that builds on existing virtualization technologies.

RestFS: resources and services are filesystems, too

We have designed and implemented RestFS, a software framework that provides a uniform, configurable connector layer for mapping remote web-based resources to local filesystem-based resources, recognizing the similarity between these two types of resources. Such mappings enable programmatic access to a resource, as well as composition of two or more resources, through the local operating systems standard filesystem application programming interface (API), scriptable file-based command-line utilities, and inter-process communication (IPC) mechanisms. The framework supports automatic and manual authentication. We include several examples intended to show the utility and practicality of our framework.

Online Layered File System (OLFS): A layered and versioned filesystem and performance analysis

We present a novel form of intra-volume directory layering with hierarchical, inheritance-like namespace unification. While each layer of an OLFS volume constitutes a subvolume that can be mounted separately in a fan-in configuration, the entire hierarchy is always accessible (online) and fully navigable through any mounted layer. OLFS uses a relational database to store its layering metadata and either a relational database or any (virtual) host file system as its backing store, along with metadata and block caching for improved performance. Because OLFS runs as a virtual file system in user-space, its capabilities are available to all existing software without modification or special privileges. We have developed a reference implementation of OLFS for FUSE based on MySQL and XFS, and conducted performance benchmarking against XFS by itself. We explore several applications of OLFS, such as enhanced server synchronization, transactional file operations, and versioning.

Simplifying domain modeling and memory management in user-mode filesystems with the NOFS framework

Transparent access to remote data sets and data arising from web services is a non-trivial challenge to application developers. This early stage work addresses this challenge with NOFS, an object-oriented framework for creating filesystems to support domain specific functionality. While an early stage work, we present a solution to solve the access problem. Our solution greatly simplifies the task of filesystems development by providing the glue code needed between a domain model and the filesystem contract. We demonstrate support for domain models that are larger than physical memory and demonstrate how the concerns of caching can be removed from user-mode filesystem implementations. Future work will addresses more robust solutions to caching and other performance strategies.