simulation@uflorida.cis.ufl.edu (Moderator: Paul Fishwick) (01/03/90)
Volume: 13, Issue: 3, Wed Jan 3 09:46:20 EST 1990
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| TODAY'S TOPICS |
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(1) UDL/I High Level Design Language
(2) TR: Determining GVT in Time Warp Simulation
(3) TR: Protocols for Parallel Logic-Level Simulation
(4) Simulation of Data Flow Architectures
(5) Simulation for Factory Automation
* Moderator: Paul Fishwick, Univ. of Florida
* Send topical mail to: simulation@bikini.cis.ufl.edu OR
post to comp.simulation via USENET
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* Simulation Tools available by doing above and changing the
directory to pub/simdigest/tools.
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Posted-Date: Tue, 19 Dec 89 18:59:55 CST
Date: Tue, 19 Dec 89 18:59:55 CST
From: steve@titan.tsd.arlut.utexas.edu (Steve Glicker)
To: simulation@ufl.edu
Subject: The UDL/I HDL
In the December 18th issue of EE Times a front page article entitled
"Japan Plans HDL" begins,
"Tokyo - A powerful group of Japanese companies, spearheaded by NTT
Corp., is hammering out a high-level design language called UDL/I.
When complete, the Unified Design Language for ICs will be proposed as
a Japan Industrial Standard, raising questions about the future of
VHDL, the emerging hardware-description language standard." ...
The article indicates that UDL/I is in its early stages. Does anyone
know how to obtain a draft of this proposed standard?
Steve Glicker
(steve@titan.tsd.arlut.utexas.edu)
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Date: Tue, 26 Dec 89 11:49:03 -0800
From: liny@cs.washington.edu (Yi-Bing Lin)
Return-Path: <liny@cs.washington.edu>
To: fishwick@bikini.cis.ufl.edu
Subject: Determining GVT in Time Warp simulation
The following technical report (TR 90-01-02) can be requested via
e-mail: tech-report@june.cs.washington.edu
DETERMINING THE GLOBAL VIRTUAL TIME IN A DISTRIBUTED SIMULATION
Yi-Bing Lin and Edward D. Lazowska
Department of Computer Science and Engineering
University of Washington
Seattle, WA 98195
ABSTRACT
The virtual time paradigm is a method of organizing and synchronizing
distributed systems. An implementation of this paradigm, called the
Time Warp mechanism, is one of the most important parallel simulation
protocols. The Time Warp synchronization mechanism takes an
optimistic approach in which a process executes every message as soon
as it arrives. If a message with an earlier timestamp subsequently
arrives, the process rolls back its state to the time of the earlier
message and re-executes from that point. Thus, the state of each
process must be saved regularly (regardless of whether or not
rollbacks actually occur).
The amount of storage used for state-saving grows as the simulation
progresses. Jefferson observed that at any real time there exists a
global virtual time GVT such that all executed messages with timestamp
earlier than GVT will not be rolled back. Thus the storage used for
saving information with timestamp earlier than GVT can be reclaimed.
In addition to garbage collection, GVT can be useful in other areas of
Time Warp simulation such as termination detection, snapshots and
crash recovery, input and output handling, etc.
The task of finding GVT is not trivial in a distributed environment.
The approach used in most distributed Time Warp implementations is
based on Samadi's algorithm. This algorithm requires acknowledgement
messages, which introduce heavy network traffic. This paper proposes a
new algorithm that does not require acknowledgement messages,
eliminating 50\% of the network traffic in Time Warp simulation. A
data structure used in our algorithm can also be used to detect lost
messages in an unreliable environment.
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Date: Tue, 26 Dec 89 11:56:49 -0800
From: liny@cs.washington.edu (Yi-Bing Lin)
Return-Path: <liny@cs.washington.edu>
To: fishwick@bikini.cis.ufl.edu
Subject: protocols for parallel logic-level simulation
The following technical report (TR 89-09-06) can be requested via
e-mail: tech-report@june.cs.washington.edu
COMPARING SYNCHRONIZATION PROTOCOLS FOR PARALLEL LOGIC-LEVEL SIMULATION
Yi-Bing Lin and Edward D. Lazowska
Department of Computer Science and Engineering
University of Washington
Seattle, WA 98195
Mary L. Bailey
Department of Computer Science
University of Arizona
Tucson, AZ 85721
ABSTRACT
Recently there has been a great deal of interest in parallel
event-driven logic-level simulation as a means of alleviating the
simulation bottleneck in VLSI design. This paper compares different
synchronization protocols for parallel logic-level simulation. The
protocols investigated are the synchronous protocol, the Chandy-Misra
protocol, the Time Warp protocol with aggressive cancellation, and the
Time Warp protocol with lazy cancellation. An artificial protocol,
called the {\it conservative optimal protocol}, is used as a basis for
this comparison. Under the assumption that every process is assigned
to a dedicated processor, we show that the conservative optimal
simulation outperforms both the synchronous simulation and the
Chandy-Misra simulation, and that the Time Warp simulation with
aggressive cancellation and the Time Warp simulation with lazy
cancellation both outperform the conservative optimal simulation.
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To: comp-simulation@rutgers.edu
Path: bimacs!ariel
From: ariel@bimacs.biu.ac.il (Ariel J. Frank)
Newsgroups: comp.simulation
Subject: Simulation of (data flow) architectures
Keywords: simulation, architecture, dataflow, software
Date: 21 Dec 89 09:36:33 GMT
Organization: Math & CS, BarIlan U, Ramat-Gan, Israel
Hi Simulation Land. I'm new to this group so please indilge with me.
I need your collective advice on a suitable PD (or reasonablly priced)
software system for developing a simulation program and/or simulating
computer architectures and especially data flow oriented ones. The
idea is to simulate at the object level but objects can be at a low
level and there can be many of them. The setup has to be well
documented and easily usable (for architecture guys). Preferences to
UNIX setups for VAXen, VAXStations or SUNs.
Any info, facts, advice, insight will be appreciated. Please E-mail
and I will summerize if enough interest. Thanks in advance, Ariel.
--
Ariel J. Frank
Deputy Chairperson, Dept. of Mathematics and Computer Science
Bar Ilan University, Ramat Gan, Israel 52100
Tel: (972-3-) 5318407/8, Fax: (972-3-) 344766
BITNET: ariel@bimacs (also F68388@barilan)
INTERNET: ariel@bimacs.biu.ac.il
ARPA: ariel%bimacs.bitnet@cunyvm.cuny.edu
CSNET: ariel%bimacs.bitnet%cunyvm.cuny.edu@csnet-relay
UUCP: ...uunet!mcvax!humus!bimacs!ariel
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To: uunet!comp-simulation@uunet.UU.NET
Path: cme!durer!newton
From: newton@cme.nist.gov (Eric Newton)
Newsgroups: comp.simulation
Subject: novice questions on available software
Date: 2 Jan 90 18:26:07 GMT
Sender: news@cme.nist.gov
Distribution: comp
Organization: National Institute of Standards and Technology
Hi, I am hoping that some of you experts out there in netland could
help me.
A group here is attempting to build a system to integrate software
packages for factory automation. Simulation is one of the systems
that we would like to integrate. Unfortunately, none of us has much
experience with simulation packages currently available. I am
soliciting your advice for such packages.
We are *not* looking for 3D graphics packages that will simulate
machinery or robots moving on the shop floor. We *are* looking for
packages that will simulate the data flow and timing requirements of a
system.
We have a variety of resources to run such a system on: Macs, PCs,
Sun 3s, SGI Personal 4D, a Symbolics lisp machine. The cost of the
software is important, but the flexibility of the system should have
highest priority. Public Domain(ish) code or source is highly
desirable.
We could use any advice/opinions you might have.
-Eric
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
newton@cme.nist.gov Eric C. Newton
Computer Scientist
(Looking for something witty to put here) NIST (formerly NBS)
Gaithersburg, MD 20899
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