Newsgroups: comp.parallel.pvm
From: Tudor Buican <tudor@timb.com>
Subject: Updated notes on WPVM and a workaround
Organization: Rt66.COM, Public Internet Access in New Mexico
Date: Tue, 09 Apr 1996 09:37:08 -0600
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Message-ID: <316A8424.5F97@timb.com>

First of all, my news server is to blame for the multiple copies of my 
previous posting. Sorry!

First, some updates on using WPVM. I found it to work reliably under NT 
5.31 (WPVM 16). Under Win95 (WPVM 32), it's very temperamental but can 
be used. The main problem is connecting to a listener. On my system, the 
listener often refuses to respond and I get an error message on the 
master. The workaround is the following:

1. From the master, choose the slave and click "Add". Nothing happens.
2. Run over to the hoped-for slave, which had been set up to "listen". 
Nothing's happened there either.
3. Open the initialization window, click on "stopped" and then "OK".
4. Open the initialization window again and click on "listen".
5. At about this point, several things may happen:
	a. The console shows that a connection is actually being 
made and the initialization window shows "slave" (as it should have done 
long before);
	b. An error message appears, complaining about winsock. Just 
click "OK", and everything will be so.
	c. The console shows the connection being made only after 
closing the initialization window a second time by clicking its "OK" 
button.

Each machine on my network seems to have its own preferences in terms of 
a, b, and c above. It's crazy, but it works -- once things are 
connected, PVM applications seem quite happy.

This workaround supplements my updated notes, which follow:

========================================================================- All host names in the configuration file must be fully qualified (i.e. 
"workhorse.timb.com" is fine, but merely "workhorse" is not); 
- All entries in the configuration file must contain both the lo option 
with user name and "pw" or "so=pw", even though WPVM will treat the pw 
options as errors; 
- However, when adding a Win95 or NT machine), leave the user and pw 
fields in the initialization window blank.  
- Win hosts to be added should be set up on "listen". Of course, the 
master should be set as "master". 
- If switching between modes (i.e., "listen", "master", "slave", etc.), 
go through "stopped" first (in most cases, it won't work unless one does 
this). 
- When a "listener" is added, it becomes a "slave". 

   THE FUNNY PART: If a listener refuses to be added, change it to 
"stopped", then back to "listen". It
will usually accept being added, even though it may give a message 
saying that winsock doesn't exist, in which case just click "OK" and 
everything will, indeed, be OK! 
==================================================================

One would suspect there are some buffers that don't get flushed unless 
one goes through the listen-stopped-listen cycle. I'm sure it's a 
problem that the developers in Coimbra (from whom I still haven't heard) 
could easily fix. Then we would have a really nice Windows PVM, 
provided, of course, it would come up directly in "listen" mode rather 
than require extra handling by the user.

Please let me know if this is any help. Good luck!

Tudor

