Alpine is a file system that supports atomic transactions and is designed to operate as a service on a computer network. Alpine's primary purpose is to store files that represent databases. An important secondary goal is to store ordinary files representing documents, program modules, and the like. Unlike other file servers described in the literature, Alpine uses a log-based technique to implement atomic file update. Another unusual aspect of Alpine is that it performs all communication via a general-purpose remote procedure call facility. Both of these decisions have worked out well. This paper describes Alpine's design and implementation, and evaluates the system in light of our experience to date. Alpine is written in Cedar, a strongly typed modular programming language that includes garbage-collected storage. We report on using the Cedar language and programming environment to develop Alpine.

Pup is the name of an internet packet format (PARC Universal Packet), a hierarchy of protocols, and a style of internetwork communication. The fundamental abstraction is an end-to-end media-in dependent internetwork datagram. Higher levels of functionality are achieved by end-to-end protocols that are strictly a matter of agreement among the communicating end processes. This report explores important design issues, sets forth principles that have guided the Pup design, discusses the present implementation in moderate detail, and summarizes experience with an operational internetwork. This work serves as the basis for a functioning internetwork system that provides service to about 1000 computers, on 25 networks of 5 different types, using 20 internetwork gateways.

This paper discusses a number of issues relevant to the design of systems for performing interactive graphics over a computer network such as the ARPA Network. We then describe a working implementation of such a system and an example of its use.