Remote access feels different from local access. The major issues are consistency (machines vary in GUIs, applications, and devices) and responsiveness (the user must wait for network and server delays), Protium attacks these by partitioning programs into local viewers that connect to remote services using application-specific protocols. Partitioning allows viewers to be customized to adapt to local features and limitations. Services are responsible for maintaining long-term state. Viewers manage the user interface and use state to reduce communication between viewer and service, reducing latency whenever possible. System infrastructure sits between the viewer and service, supporting replication, consistency, session management, and multiple simultaneous viewers. The prototype system includes an editor, a draw program, a PDF viewer, a map database, a music jukebox, and windowing system support. It runs on servers, workstations, PCs, and PDAs under Plan 9, Linux, and Windows; services and viewers have been written in C, Java, and Concurrent ML.

Abstract The DEMOS/MP operating system has moved from a supercomputer with a simple addressing structure to a network of microcomputers. This transformation was done without significant changes to the semantics of the original DEMOS, i.e. existing DEMOS programs should run on DEMOS/MP. The changes to DEMOS were simplified by the structure of its primitive objects and the functions over those objects. The structure of DEMOS links and processes were the major contributors to the simplicity. The changes made to produce DEMOS/MP involved the internal structure of link, modification to parts of the kernel, and limited changes to the various system processes.

Publishing is a model and mechanism for crash recovery in a distributed computing environment. Published communication works for systems connected via a broadcast medium by recording messages transmitted over the network. The recovery mechanism can be completely transparent to the failed process and all processes interacting with it. Although published communication is intended for a broadcast network such as a bus, a ring, or an Ethernet, it can be used in other environments.