md@ecs.soton.ac.uk (Mark Debbage Puma) (01/11/91)
The Virtual Channel Router
4th January 1991
Mark Debbage, Mark Hill, Denis Nicole
University Of Southampton
Introduction
------------
The Virtual Channel Router (VCR) is a software package developed at
the University Of Southampton within the Esprit P2701
PUMA project to provide unrestricted channel
communication across networks of T-series transputers. It allows
distributed transputer programs to be written, compiled and
configured in a topology-independent format and then bound to a
topology-dependent routing kernel at run-time.
The system is based on a virtual occam compiler/configurer
developed by Inmos for H1 simulation. VCR allows H1-style programming
techniques to be employed on current generation hardware, easing the
learning gap between today's and tomorrows's technologies.
Features
--------
1. Provides occam channel communications over networks of
32-bit T-series transputers.
2. The VCR routing kernel is deadlock-free and places no
restrictions on message size.
3. Source-level interface from occam is pure occam - virtual
outputs by !, virtual inputs by ? and virtual channel
alternation by ALT.
4. Configuration-level language is a simplification of the
occam Toolset standard with link placement eliminated and the
processor's valency limit removed. In addition, a channel array
constructor allows arbitrary channel slices to be passed into user
code simplifying the expression of regular topologies.
5. The suite of 3L scientific languages (C, Pascal and FORTRAN)
can be bound into VCR programs using library calls and an occam
harness.
6. VCR user programs are completely independent of the target VCR
network - the user configuration level can be written without
knowledge of the machine topology or the target number of processors.
7. VCR applications binaries are truly portable (memory sufficing)
between all machines running the same release of the VCR kernel,
provided that the binaries are processor type independent.
For example, multi-processor applications can be developed and tested
on a single processor and the same binary then run on a network.
8. This release of VCR is targetted at intrinsically deadlock-free
networks. A large number of VCR topologies are provided for both
fixed link and reconfigurable machines. VCR can be configured for
other deadlock-free networks by modifying the router and recompiling.
9. Limited source-level debugging using the standard tools.
10. Latency and processor consumption are comparable to the fastest
transputer routing kernels, but no other matches the simplicity of
VCR's user interface.
11. VCR forms an extension to the Inmos occam Toolset (not
the new occam and C Toolsets) and is available for Sun- and
PC-hosted transputer networks.
Availability
------------
The Virtual Channel Router, the accompanying documentation and the
virtual occam compiler are licensed free of charge and
distributed at media cost. Hence, the system is supplied with no
warranty and support is entirely discretional.
VCR is available to the H1 Developer's Club through Inmos.
It is also distributed through,
Transputer Technology Solutions
2 Venture Road
Chilworth Research Centre
Southampton
SO1 7NP
United Kingdom
A media charge of \pounds 50.00 will be made. This fee covers both
the current release of VCR (version 1.8c), and a future release (see
hereafter) to be distributed around April 1991.
Next Release Of VCR
-------------------
VCR is still under development; the next release will include the
following features :
Automatic reconfiguration onto arbitrary networks.
Full support for the new Inmos occam and C Toolsets.greeny@wotan.top.cis.syr.edu (Jonathan Greenfield) (01/24/91)
Can anyone give me a reference to a technical report describing the VCR system? Also, does anyone have some basic performance results for the system, like average message latency, CPU utilization, etc. (particularly when used with occam)? Thanks. Jonathan