From: bernardl@cs.Stanford.EDU (Bernard Lee)
Newsgroups: fj.mail-lists.parallel
Subject: iPSC emulation library on SGI
Date: 24 Jul 92 11:54:42 GMT
Distribution: fj

=======================================================
Availability of the DASH or SGI message-passing library
=======================================================

After having cleared up some legal details, (one disadvantage for
having  too  many sponsors...) the DASH team of the Stanford Com-
puter Systems Laboratory is pleased to announce the  availability
of  the  iPSC  message-passing  library  for public distribution.
This distribution is intended for  non-commercial  purposes only.
As  you probably realize, Stanford University reserves all of its
commercial rights to this library.

The  library  is  now  available  through  anonymous   ftp   from
mojave.stanford.edu, under the directory:

   /pub/dash-msg-library

which sits parallel to the splash and tango directories.

Please read the legal notice in that directory prior to download-
ing any software.  By downloading any portion of the library from
mojave, you have agreed to abide by that legal notice.

The library will be updated from time to  time.   Therefore,  you
are asked to send e-mail to (all three addresses):

   kellyj@leland.stanford.edu
   bernardl@vnet.ibm.com
   pleong@oracle.com

after downloading the library, so that we can keep  you  informed
of future updates.

Please notice that the development team is NOT under  obligations
to  Stanford  or  any  of the sponsors of this project to support
this library.  Nonetheless, we  do  welcome  informed  and  well-
researched questions, and they will be answered as time is avail-
able.

All questions and answers will be logged in a  FAQ  file  in  the
dash-msg-library  directory.  You are asked to review  that  file 
before sending any email to the development team.

Thank you.




==========================     
Frequently Asked Questions
==========================


(1) What is the minimum number of processors that I will need  on
my SGI to run the library?

One theoretically.  Although the current  distribution  does  not
support  virtual processors.  So, it will not be very interesting
to have a host program running by itself.


(2) Does the library represent an implicit admission  of  "flaws"
in the single address-space model?

No.  The library is developed so that we can run iPSC programs on
the  DASH  and  to  test  out  codes  under  a  "hybrid"  shared-
memory/message-passing mode.


(3) Is the library inherently inefficient because the development
team was restrained by the iPSC interface?

Not really.  The major inefficiency comes from UNIX and its  lack
of support for parallel-processing. Which interface we choose has
very little to do with it. We will gradually migrate the  library
out of UNIX-dependent codes into a tailored-made microkernel.


(4)  Is it trivial to emulate message-passing on a shared- memory
architecture?

The answer may be 'Yes' on a  CS  exam.   Unfortunately,  we  are
writing  a  library  for industrial-quality codes, and just about
anything that can break will break.    Memory  management,  stack
overflow, etc...  They all need to be taken into account.


(5)  What is the most popular use of the library right now?

Developing iPSC code on an SGI.

(6)  Can I contribute to the library?

Yes. You will lose all of your royalties rights on your contribu-
tions,  although you can be assured that you will NEVER be short-
changed on acknowledgements.  In fact, we are making an effort to
turn  this library into another X-window like consortium.  If you
can use our codes, why waste your time to write your own?  If you
develop  anything  out  of our codes, we are glad to integrate it
into the public distribution for you.