Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!mcnc!uvaarpa!murdoch!news
From: tg2r@dale.acc.Virginia.EDU (Todd Greenwald)
Newsgroups: comp.os.os2
Subject: Distributed Processing/Broadcasting
Message-ID: <1990Jul1.023719.29550@murdoch.acc.Virginia.EDU>
Date: 1 Jul 90 02:37:19 GMT
Sender: news@murdoch.acc.Virginia.EDU
Distribution: usa
Organization: University of Virginia
Lines: 33

Here's a puzzler I could sure use help on.  I thought, at first
glance that this would be easy....

I'm developing a multiuser distributed processing application based
on a client-server model.  When one client alters data, the server
is notified and then 'broadcasts' the change to all other registered
clients.  

Initially, I thought that the Database Manager could handle this easily;O
and indeed it can handle most of the problems.  It's   the broadcasting
that it can't deal with. (Or that I can't make it deal with!)  

So I moved over to namedpipes.  The server opens a new thread to maintain
a namedpiped with each client that registers with the system.  Using
DosTransactNmPipe, it is easy for the client to notify the server of any
changes, but still the nagging problem of the broadcast.

A few experiments left me with the conclusion that DosTransactNmPipe
can run from client to server and not vica versa.  (If it could I'd 
be set).

I've thought about mailslots, but initial investigation has left me
with the impressions that 1) second-class delivery is not secure enough
for my needs and 2) remote broadcasting, though supported for messaging,
is not supported for mailslots. (I'm using IBM EE 1.2 and Lan Server 1.2)

In short, I'm trying to mimic the logic of an airplane tracking system.
All monitors are notified, in real time, of any 'flights' arriving or
departing.

C
Any thoughts on this puzzlaar (for those caar talk fans!) ?