Report Number: CS-TR-86-1137
Institution: Stanford University, Department of Computer Science
Title: The Leaf File Access Protocol
Author: Mogul, Jeffrey
Date: December 1986
Abstract: Personal computers are superior to timesharing systems in many ways, but they are inferior in this respect: they make it harder for users to share files. A local area network provides a substrate upon which file sharing can be built; one must also have a protocol for sharing files. This report describes Leaf, one of the first protocols to allow remote access to files. Leaf is a remote file access protocol rather than a file transfer protocol. Unlike a file transfer protocol, which must create a complete copy of a file, a file access protocol provides random access directly to the file itself. This promotes sharing because it allows simultaneous access to a file by several remote users, and because it avoids the creation of new copies and the associated consistency-maintenance problem. The protocol described in this report is nearly obsolete. It is interesting for historical reasons, primarily because it was perhaps the first non-proprietary remote file access protocol actually implemented, and also because it serves as a case study in practical protocol design. The specification of Leaf is included as an appendix; it has not been widely available outside of Stanford.