Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!ucsd!ucbvax!bloom-beacon!ncd.COM!lemke
From: lemke@ncd.COM (Dave Lemke)
Newsgroups: comp.windows.x
Subject: Re: OW as a PostScript X server...
Message-ID: <9011132205.AA28794@hansen.com>
Date: 13 Nov 90 14:05:26 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 36


  From:  uunet!fis1138.govt.shearson.com!fgreco (Frank Greco)
  Date:  Tue, 13 Nov 90 13:43:55 EST

  > 
  > The technical problem with the X11/NeWS merged server is the following:
  > 
  > If you want to mix X and PostScript based imaging models (and I know people
  > who do, for very good reasons; each imaging model has much to offer the
  > application programmer), you have to synchronize the two connections.  This
 is 
  > more than a minor pain to an application programmer in this cicumstances
  > (and can be a non-trival performance problem; it basically involves putting
  > XSync calls and equivalent everywhere you care about order, which requires
  > a server round trip); and comes naturally if you are talking to a server 
  > over a single connection.
  
  	I don't get it.  Why is this a "technical problem" with the X/NeWS
  	merged server?  It is a concern wherever you want to mix imaging models.

because the two different protocols are coming over two different
connections.  the xnews server treats them as two different clients,
and makes no guarentees about the order in which their requests are
processed.  its the same problem as two X clients drawing to the same
window -- its server dependent which one draws first.  and this can be
a major problem if you're using destructive rop codes, or overlapping
graphics.

  	I guess DEC wouldn't have the same problem mixing Display PostScript
  	and Xlib...;->

right.  because all the requests come over the same connection, from
the same client, and are therefore guarenteed to be handled in a
predictable order.

Dave