[AG-TECH] Newb seek a bit of advice

Allan Spale aspale at evl.uic.edu
Fri Nov 1 14:01:16 CST 2002


Let me first welcome you to the Access Grid community!  Therre is a lot of
things to absorb, but once you see the interrelations between the
components, the whole concept seems to make more sense.  If it would be
helpful, I gave a presentation (PowerPoint) to many newbies about how the
Access Grid works in a *very general sense* if that would be somewhat
useful to you.  It is tilted more toward EVL/UIC, but it may be a good
starting point to understand what is possible with the Access Grid.

As for your other points...

On Fri, 1 Nov 2002, Peter Hanley wrote:

> I have been asked to facilitate several faculty being able to access 
> the November 8th broadcast of a Benoit Mandlebrot presentation being 
> transmitted via accessgrid. Although the best possible scenario is 
> being able to fully participate, it doesn't seem to be possible for us 
> to build a node by the 8th.
> Currently I have installed the AG 1.2 Release on a PIII-800 with 256 
> megs of ram, and have not been able to either connect to the MUD nor to 
> a video screen. I'm not sure if the reason I can't connect is because I 
> have configured something incorrectly, or becasue there was nothing to 
> connect to when I was trying it. It has been difficult for me to sort 
> through the documentation on the website, I think especially because I 
> had only a half idea of what accessgrid is...

If you installed the single machine recommendation, then you should be ok.
EVL/UIC has a single node computer with very similar specifications to
what you are using; however we have a lot more memory.  If you are going
to go the single computer route, I would highly recommend adding maybe 500
MB more just so that there is plenty of memory available for everything.

One projector will have things be a bit cramped.  I am assuming that you
are using a dual-head video display card so that you have one display for
the PC for your node operator to run the session and a display for the
projector (not required, but it is helpful).  

As far as AG usage...

When you start the software, four Java-windows should appear: an event
server listener, a video resource manager, a display resource mangager,
and an audio resource mangaer.  These resource managers receive cues from
the event-server listener.  The event server listener takes its cue from
the web browser that allows you to move to the different venues on the
Access Grid web pages (http://venues.accessgrid.org...make sure to
register for a login). 

After you login, you will be "transported" to the enterance venue called
the Access Grid Lobby.  As a side note, the designers of the Access Grid
(which is referred to as AG), wanted to create a real-world metaphor, so
they have decided to use a room/venue metaphor.  You can think of it as a
multimedia MUD if that would help.  The hyperlinks presented on the Access
Grid Lobby page will allow you to "walk" to the connecting room.  One bit
of etiquette...when you are not in a meeting, transmit audio and video to
the Lobby.  If you need to do testing, move to the Test Room.  All other
rooms are either public and require a reservation or private and not
available for use by anyone but the owners (not technically but in terms
of etiquette).

Once you click on a link or login for the first time, the MIMEs connected
to the web pages will be downloaded and will affect the MUD and event
listener.  The event listener will display the venue you are currently in. 
It will then trigger the audio and video resource managers to load RAT and
VIC, respectively, with the correct multicast address (multicast is
important to the AG, but workarounds are available).  Additionally, the
display resource manager will cause another instance of VIC to appear.
The different between the display-VIC and the video-VIC is that the
video-VIC allows you to transmit video, while the display-VIC prohibits
video transmission because it was designed to optimize displaying the

By default, RAT does not transmit audio, but VIC does transmit video by
default.  Regardless, you can tweak the settings if necessary once things
appear correctly.  If you have tkMOO-light correctly installed and have a
MUD character, the MUD should move you to the appropriate room.  As for
using the MUD, here are a few simple tips.  To talk to everyone, precede
your message with ".  To talk to a particular person, use this format
<character-name>, <message>.

If none of this works the way you would expect, consider the following
workaround.  There is not a tight coupling of the software components in
the AG framework.  As a result, you can use the RAT and VIC programs
independently of the AG, so to speak.  All you have to do is obtain the
multicast addresses for the audio data and video data.  Then, run VIC and
RAT in the following manner...

vic -t 127 <IP>/<PORT>
rat -t 127 <IP>/<PORT>

Then you can go into VIC and RAT and make the necessary changes.  One
caveat, when you run VIC, make sure you run the instance of VIC that does
not just display video (which would be named ddvic or something).

As a side note, try to join the AG technical mailing list by subscribing
to ag-tech at mcs.anl.gov.  There you can post technical questions and other
AG related messages.

Best of luck with your new AG node.

AG Node Operator

> I have a few questions that I've tried to answer with the 
> documentation, but I think that a confluence of factors is working 
> against me...so I thought I'd ask a few basic questions of the list, 
> hoping that the answers aren't in an obvious place and assuming that 
> they are fairly easy to answer...
> 1) Is it possible to view a Accessgrid presentation using a single 
> PIII-800 with 256 megs of ram and a single projector? If not, what is 
> is the minimum amount of hardware to view a transmission? Does this 
> even make sense? In other words, is it even possible to set up a 
> display only system?
> 2) Is anyone aware of a guide on how to set up a system for simply 
> viewing a presentation on the grid?
> 3) If either 1 or 2 is possible, is there a way for me to test my 
> constructed system before the 8th of November (the Mandlebrot 
> presentation)?
> Thank you very much in advance,
> Peter

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