Abstract: A multi-processor, multi-tasking virtual machine comprises processes, messages, and contexts. Processes communicate only through messages. Processes may be grouped into contexts of related processes. Communication may be made between processes in different or related contexts or at the same context level.According to one message transmission mode, a message may be sent to each process with a given name within one context, thus ensuring that all processes with the same name at the same context level can be communicated with individually without knowing how many there are or where they are located.

Abstract: A data management system used by a digital computer system comprises a plurality of individual file systems which are connected together in a logical ring configuration around which file requests travel. File requests may be transmitted by the user to the "next" file system in the ring relative to the user.File requests optionally may or may not specify a file system name. If a file system name is specified, then the request is forwarded unidirectionally around the logical ring until either that file system name is found or the request returns to its starting point. If no file system name is specified, then an attempt is made to satisfy the request on each file system in turn until either the request is satisfied or the request returns to its starting point.

Abstract: A multi-processor, multi-tasking virtual machine comprises processes, messages, and contexts. Processes communicate only through messages. Contexts are groups of related processes.The virtual machine makes all hardware devices appear to be processes, in that the occurrence of an event on a device causes a message to be generated and sent to another process for handling. The receiving process performs all operations required to handle the event. Thus a variety of hardware devices can be connected and disconnected from the system without interrupting its operation and without necessitating extensive software revisions.

Abstract: A multi-processor, multi-tasking virtual machine comprises processes, messages, and contexts. Processes communicate only through messages. Contexts are groups of related processes. The virtual machine is implemented in a distributed data processing system comprising a plurality of individual cells coupled by a local area network (LAN). Each cell may comprise one or more processes and/or contexts.A network interface module (NIM) provides the interface between any individual cell and the LAN. To facilitate message transmission between processes resident on different cells, each NIM provides addressing modes allowing messages to be sent to processes according to the processes' names. Cells may be added to or deleted from the LAN, and processes may be created or deleted, without disrupting the LAN operations.