SDI Seminar

Speaker: John H. Howard, Sun Microsystems

Date: November 17, 1999
Time: 1 PM
Place: Wean Hall 7220

A File System for Mobile Computers: the Reconcile Program


Reconcile started out as an experiment: can you maintain complete copies of your working environment on multiple computers, connecting them only when re-synchronizing the copies? Will users accept on-demand synchronization and will they be able to deal with visible file system replication? Can a reconciliation algorithm be found that does not need operating system or application program modifications, is robust against inaccurate system clocks and other oddities in local file systems, and operates across various flavors of Unix and Windows?

The experiment has evolved into a tool which has been in daily use at MERL for several year. While replication of user and project directories is still the primary application, it has expanded to support file system backup and the release process for MERL's web site. A beta testing program not only uncovered many bugs and unanticipated requirements, but also pushed Reconcile's scalability to the level of hundreds of gigabytes worth of files. Most recently Reconcile is being licensed to third parties, for both direct distribution and incorporation in proprietary storage management suites.

This talk will cover the history of the project, the unique journal merging technology it uses, and the lessons learned from it. I'll also say a few words about my new work at Sun.


John H. Howard
Distinguished Engineer
Sun Network Storage

John Howard received his Ph.D. from the University of Texas at Austin in 1970, where he helped to develop an early clustered timesharing system for CDC 6600s. At IBM San Jose's Storage Systems and Technology department he developed a VM/370 based emulator and applied it to disk caching and other storage architecture issues. In 1982 he joined the Andrew project at CMU, managed the development of AFS and eventually becoming director of the ITC. He moved on to Mitsubishi Electric Research Labs (MERL), Cambridge, in 1992, where he continued his file system research as well as participating in a high-speed networking project. Recently he joined Sun Microsystems as a Distinguished Engineer with the goal of advancing file system in the context of storage networks and modern devices and interconnects.