XINU

Developed by:
Purdue University, USA Douglas Comer, Fossum, Munson, and Stevens

Short Description:
XINU is an operating system with an elegant, hierarchical design which is easy to understand. Later it was extended by internetwork communication, remote interprocess communication, and a remote file system. XINU internetworking supports address determin ation at boot time, address resolution at run time, a syntactic name space and a protocol for name resolution. An interesting part of the XINU remote file system is the stateless fileserver.

Model: workstation, minicomputer, heterogeneous, client/server, loosely-coupled, partially integrated, multiple-instance, monolithic
Properties: UNIX-compatible, virtual memory, WAN support, datagram, standard protocols, synchronization, encryption, identity based, preemptive multitasking, name servers, global traditional hierarchical naming, synchronous message passing
Transparency: location, naming
Running on: Sun, IBM PC, DEC VAX 11/780, MicroVax
Date: 01.01.84 Ð ?

References:
Douglas Comer: ãOperating System Design Vol. 1 The Xinu ApproachÓ, 1984, ISBN 0-13-637539-1, Prentice Hall, College Marketing Department, Englewood Cliffs

Douglas Comer: ãOperating System Design Vol. II Internetworking with XinuÓ, 1987, ISBN 0-13-637414-X

Developed by:
School of Information Science, Portsmouth Polytechnic, UK S. J. Pratt

Short Description:
Alchemy is a three-dimensional distributed operating system model, which reflects both the interfaces between the distributed operating system kernel and the local standalone operating system, and the amount of indirect interfacing between individual node s to effect global control. Segmenting and distributing the global control functions throughout the network will depend upon the individual processorÕs spare capacity for performing such additional tasks. Conversely application processes may be sent to th e nodes where the demand placed upon it by effecting global control issues are least. As a consequence it is conceivable that one or more nodes would be supportive servers leaving the reminder nodes with the simple function of monitoring and reporting upo n user application processes.

Model: heterogeneous, multiple-instance DOS
Properties: process migration, loadbalancing
Transparency: location, access
Running on:
Date: 1986

References:
S. J. Pratt; "The Alchemy Model: A Model for Homogeneous and Heterogeneous Distributed Computing System". ACM Operating System Review, Vol. 20, No.2, April 1986, pp. 25-37.

Developed by:
Carnegie-Mellon University, Pittsburgh, USA R. F. Rashid, R. Fitzgerald, G.G. Robertson, L. R. Walmer, R. V. Baron, M. R. Thompson and M. Young

Short Description:
Accent is a communication oriented network operating system kernel for monoprocessors. Interprocess communication over the network is supported by special communication processes. IPC is based on ports, message-oriented and asynchron. The kernel provides ports and processes. A single process is represented by two ports, the kernel- and the data-port. Operations concerning processes are invoked by sending the adequate message to the kernel-port. The SPICE network operating system is implemented as a collec tion of processes running above the Accent kernel.

Model: client/server, single-instance DOS
Properties: process migration, message passing
Transparency: access, location, failure
Running on: PERQ Systems Corporation PERQ T2, AMD2910
Date: 1981

References:
Rashid, R. F. and Robertson, G. G.: "Accent: a communication oriented network operating system kernel". Report CMU-CS-81-123, Department of Computer Science, Carnegie-Mellon University, Pittsburgh, Pennsylvania, USA, April 1981.

Robert Fitzgerald and Richard F. Rashid: "The Integration of Virtual Memory Management and Interprocess Communication in Accent" ACM Transactions on Computer Systems, Vol. 4, No. 2, May 1986, pp. 147-177.